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FEKO User's Manual

1. Figure 9 5 Example of the use of the AE card Parameters I 0 New excitation replaces all previous excitations 1 Additional excitation add to previous excitations I I The meaning of these parameters depends on T4 I4 0 The excitation is placed on the edge between the regions with labels Iz and 13 The positive source direction is from the side with label Iz to the one with label J3 2 Excite the edges of metallic triangles with label 2 which are connected to UTD surfaces or to a PEC ground plane as spec ified with a BO or GF card Is is not used The positive feed direction is towards the UTD region or ground plane 3 Special microstrip line feed The excitation is placed on all edges on the line between points previously specified with DP cards Tz and Iz A GF card with a conducting ground plane must be present The positive source direction is from the triangles towards the edge EIR1 Absolute value of the voltage Uo in V EIR2 Phase of the voltage Up in degrees EIR3 The port impedance if this excitation is used in connection with S parameter calculation If this field is empty or 0 the value specified at the SP card is used This value is only used if the S parameters are requested with an SP card December 2002 FEKO User s Manual 9 24 DESCRIPTION OF THE CONTROL CARDS The positive source direction as used above is the direction of the current flow through the edge The internal EMF elec
2. Care has to be taken to ensure that when two surfaces touch the common edge is part of both surfaces In figure 2 3 the edge BF is such an edge That is why the right part of the surface is not allowed to be defined as the rectangle CDEF because BF is not an edge of this rectangle December 2002 FEKO User s Manual 2 6 GENERAL COMMENTS A connection point between a segment and one or more triangles is only recognised when the beginning or the end of the segment lies on the vertex or vertices of the triangles In figure 2 5 the left side is an incorrect and the right side a correct connection here the segment is connected to six triangles When curved structures circles spheres are modelled a finer mesh may be used When connecting curved edges the same maximum edge length has to be used for both edges See the example in figure 2 6 Figure 2 5 Incorrect left and correct right connection between a segment and triangles i Figure 2 6 Incorrect left and correct right connection between curved edges EM Software amp Systems S A Pty Ltd December 2002 GENERAL COMMENTS 2 7 2 4 Utilisation of symmetry It is possible to reduce the calculation time and memory usage if symmetry is utilised This can be done by using the SY card section 8 2 34 Three coordinate planes x 0 yz plane y 0 az plane and z 0 xy plane may be defined as planes of sym
3. fe aoi ee OR N gt SAS Ss Se Figure 8 27 Example of a cone with an elliptical cross section EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 55 8 2 20 KL Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 Ky Ka Po Pn Lo LN mo ae ae ae E REAL REAL REAL REAL REAL REAL REAL REAL With this card a wedge in the PO area is defined on which correction terms for the surface current density are defined on both sides of the wedge Figure 8 28 shows a sketch Figure 8 28 Sketch illustrating the use of the KL card Parameters K The name of the begin point of the edge of the wedge K3 The name of the end point of the edge of the wedge Po A point on the o side of the wedge Py A point on the n side of the wedge Lo The label of the PO triangles that are adjacent to the wedge on the o side This means that the corresponding correction term for the o side is assigned to the PO triangles that have this label Ly The label of the PO triangles that are adjacent to the wedge on the n side This means that the corresponding correction term for the n side is assigned to the PO triangles that have this label December 2002 FEKO User s Manual 8 56 DESCRIPTION OF THE GEOMETRY CARDS 8 2 21 KR Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ry Ra R3 Ra SE ae aes mT NT REAL REAL REAL REAL REAL REAL REAL REAL With this card a circular re
4. The modify button removes the last set of lines added to the graph and replaces them with the current setting This is especially useful to change the number of frequency points but one may also change the quantity or its components This option is only available while the current graph stays unchanged Once the user has shifted focus to a different graph this option becomes unavailable The grey markers along the bottom axis indicate the discrete frequencies used by ADAPT FEKO A high density of these markers indicates results that are not smooth Note that it is possible that there is a resonance in another parameter even if the current result seems quite smooth in such a band The frequency markers can be changed and or hidden by clicking the Bottom axis button on the Main graph settings panel Note that they are constructed when a graph is created from the ADAPTFEKO results panel If continuous data is added to a previously existing graph the frequency markers will be absent 5 3 3 Edit menu This menu item is used to select editing options for graphs created in GraphFEKO EM Software 4 Systems S A Pty Ltd December 2002 THE PROGRAM GRAPHFEKO 5 17 5 3 3 1 Edit graph Select this item to activate the Main graph settings panel The basic graph settings are available for editing on this panel More advanced editing of a graph can be performed by clicking the Advanced edit button at the bottom right of the Main graph settings panel
5. explicitly the rest of the cube is generated by means of symmetry EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM TIMEFEKO 11 9 Figure 11 7 Cube with side lengths of 1m Normally TIMEFEKO will automatically insert the correct required frequency value Use the following construct so that this value used by TIMEFEKO will not be overwritten but we can still display the geometry in WinFEXO if not defined freq then freq 100 0e6 lendif Define some constants a 1 side length of the cube ttedgelen a 5 max edge length for the triangular patches Set the segmentation parameters IP edgelen Define the points DP P1 a 2 0 0 DP P2 tta 2 tta 2 0 DP P3 tta 2 tta 2 tta 2 DP P4 tta 2 0 tta 2 DP P5 0 0 a 2 DP P6 0 tta 2 tta 2 DP P7 0 a 2 0 December 2002 FEKO User s Manual 11 10 THE PROGRAM TIMEFEKO LA BP LA BP BP SY CB SY EG FR AO OS ok FF EN Create one eigth of the cube use label 1 for the front plate and label O for the rest 1 P1 P2 P3 P4 P3 P4 P5 P6 P2 P3 PG P7 Mirror around to coordinate planes so that label for front plate remains 1 all other surfaces will have label 0 x 0 yz plane only geometric symmetry y 0 xz plane ideal magnetic conducting plane z 0 xy plane ideal electric conducting plane 1 1 0 0 1 2 0 1
6. H a December 2002 FEKO User s Manual DESCRIPTION OF THE GEOMETRY CARDS 8 59 Third example of KR card usage The elliptical ring disk shown in figure 8 32 is created with the following commands Example for an elliptical plate with hole dk ta Hb c xk general parameters 1 7 radius first half axis of the hole 2 5 first half axis of the ellipse 0 9 second half axis of the ellipse segmentation ttedge_1 0 35 IP eK DP DP DP DP ek KR SY x EG EN define points A 0 B 0 C a D tc define the geometry A B C D 90 1 1 1 0 end ttedge_1 0 0 0 a 0 0 0 0 ttedge_1 ttedge_1 b a Figure 8 32 Example of an elliptical disk with a hole created by setting R4 December 2002 FEKO User s Manual 8 60 DESCRIPTION OF THE GEOMETRY CARDS 8 2 22 KU Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ri Ra R3 Ra Rs INT INT INT INT STRISTRISTRISTR NT REAL REAL REAL REAL REAL REAL REAL REAL With this card a spherical segment can be generated Figure 8 33 shows an example Parameters S Name of the centre of the sphere S2 The name of a point that indicates the Y 0 direction in a spherical coordinate system The distance between S and S2 is the radius of the sphere S3 The name of a point that indicates the y 0 direction in a spherical coordinate system The distance between S and S3 is the radius of the sphere
7. Specific Absorption Rate in a lossy dielectric etc For further information see section 5 Note that every time this item is selected from within WinFEKO the program Graph FEKO will be executed If GraphFEKO is already running with the current project out file selected rather use the Import Near fields menu item in GraphFEKO to load the near field data 3 5 5 9 Near fields Iso surface On selection of this item the near field data is loaded from the current project output file and the Near field options panel in WinFEKO is activated Note See the comments on the Apply OK and Cancel buttons in section 3 5 5 7 Note further If the checkbox next to the Near field options caption is checked then the panel is activated This means that any changes made to the options available on the panel will be applied immediately This is sometimes useful but with the panel activated rendering can become very slow Select a frequency and near field block from the lists under Data block selection If the selected data block does not contain a 3D data set i e near fields calculated for multiple x y and z components then a message No 3D data in selected block is displayed under the Iso surface setting No iso surface will thus be calculated or displayed Lines Surface Colour and Arrows under Display options do NOT have any affect on the iso surface display The Iso Value under Iso surface settings can be set to select the v
8. Thus for example for a highly directive antenna a denser grid can be used close to the main beam direction The same applies to the angles y where the permissible range is 0 360 For field angles outside the start and end values defined in the data i e for Y lt 0 V gt Ox P lt p1 or p gt gpr the field strengths EF and lad are set to zero such that a sector radiator can be realised The values at field angles within the defined range are determined by bilinear interpolation To realise a complete radiation pattern rather than a sector radiator the angles should be defined such that 91 0 97 180 y 0 and yr 360 December 2002 FEKO User s Manual 9 36 DESCRIPTION OF THE CONTROL CARDS The format of the data depends on the value of the parameter Jo el 1 ffe file With Jz 1 the radiation pattern is read form lines Is to I3 I J5 1 of a ffe file created with FEKO using the DA and FF cards All the data of the radiation pattern angles and field values are determined from the file The user should however ensure that for example the frequency is correct If an antenna is analysed with FEKO the far field can for example be exported to the ffe file in 5 angle increments using the commands DA 0 0 1 0 0 FF 1 37 73 0 0 0 5 5 Note that 37 points are used for Y and 73 for to ensure that the radiation pattern is closed see also the comment above e I gt 2 external AS
9. both increase as the number of levels increases The number of levels is determined by specifying the number of tri angles at the lowest level 1 The multilevel tree is not used 0 The number of triangles is automatically selected by the program and should be approximately optimal for most problems else The value of R4 specifies the number of triangles at the lowest level It should be larger than 2 and at least a fac tor of 10 less than the number of triangles in the problem SAVEVIS 0 Normal execution 1 The PO visibility information is stored in a vis file for later reuse 2 The PO visibility information is read from the vis file i e the calculation of the visibility information is skipped For large models this can result in considerable time saving 3 If a vis file exists the PO visibility information is read from this file Otherwise the information is calculated and saved in a vis file for later use The physical optics PO approximation can only be used for certain structures Struc tures where the antenna is situated in front of a reflector are well suited Then PO can be used for the triangles that form the reflector This results in a large reduction in computational time and memory for electrically large objects EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 83 Tf triangles polygons with different labels are to be approximated with PO then more
10. oor Oo pp 0 0 50000 00000 0 0 50000 00000 0 0 50000 00000 50000 50000 ES vyerna A OOrRrFFrFOO SO It may be imported using the commands 0 001 IP IN 3 geometry nas le 0 0 0 0 0 0 50000 50000 50000 00000 00000 00000 O 50000 2 0000 50000 1 0000 11 0 00 0 0000 o oo 0 00 00 0 0 pi o O 00UN0OoO A MH 0 0 anf oOo oO N 00 For the node points FEKO also supports 16 character wide input fields The keyword GRID in columns 1 to 4 is followed by a star and three spaces The node ID is then in columns 9 to 24 the x coordinate in columns 43 to 56 y in columns 57 to 72 and z in columns 9 to 24 of the next line for example j GRID 1 GRID 2 a 1 23 222875595 2 13 410394669 pp IP 50 000000000 50 000000000 EM Software amp Systems S A Pty Ltd K j 18 480176926 1 18 480176926 2 December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 39 e FLAG 4 Read geometry from an AutoCAD dxf file This card allows importing dxf models The dxf file must comply with the release 12 DXF format specifications It should contain meshed surfaces in the form of polylines see the discussion below and lines that will be segmented by PREFEKO as discussed below The syntax is similar to that of the ASCII FEMAP and NASTRAN cases IN 4 part_1 dxf IN 4 2 part_2 dxf 5 IN 4 3 part_3 dxf 7 10 scaling 0 1 La
11. quad and 5 tet are allowed Quadrangles are automatically subdivided into triangles along the shortest diagonal 99 End of file flag Other packet types are ignored The syntax to import PATRAN models is IN 9 part_1 pat IN 9 part_2 pat 5 IN 9 35 part_3 pat 7 10 scaling 25 4 The label selection uses the PATRAN material ID s which are converted to FEKO labels Note that scaling is supported The type selection parameter x is similar to the case for NASTRAN files and may have the following values Wire segments Surface triangles o N e Tetrahedral volume elements 16 Points 32 Quadrangles divided into triangles 64 Points but only those used by the imported geometry December 2002 FEKO User s Manual 8 46 DESCRIPTION OF THE GEOMETRY CARDS As when importing neu files the wire radius must be set with the IP card preced ing the IN card and an ME card must be used when specifying dielectric surfaces in the same way as when the IN card is not present The user can also import points from the PATRAN file similar to importing points from FEMAP or NASTRAN files The points defined in the PATRAN file will then available in PREFEKO as points as if they were defined by DP cards of the form Txxx where xxx is the index of the grid point This may be used for example to attach additional structures to the geometry In addition the coordinate values of the point are available as variables in PREFEKO For example the v
12. see more detail on advanced editing in the following section The basic graph settings available for editing are e Graph titles Type in the required graph titles in the appropriate edit boxes available under Graph titles The corresponding title on the active graph window will change while typing Fonts and other graph title settings can be changed using advanced editing e Graph settings The Auto scale option is selected by default The minimum and maximum values for the active graph are displayed in the Left axis min and Left axis maz edit boxes Type a minimum or maximum value into these edit boxes to override auto scaling On changing the minimum or maximum values the Auto scale option is unselected Normalisation can be off each plot can be normalised to its maximum or all plots can be normalised to the graph maximum The Norm type drop down list gives the different normalisation options available Linear normalises the data between 0 and 1 Log and dB between minus infinity and 0 Note that the user has to select the correct normalisation type for the current graph Unselect the Normalisation checkbox to display the data without normalisation The Legend option is selected by default When selected the legend associated with each line on the active graph is displayed Unselect this option to remove the line legends from the active graph The Bottom axis button at the bottom of the panel allows scaling and adding an offset to t
13. 3 1 4 Graphics card With properly installed graphics cards that support 3D OpenGL hardware rendering the user should see a considerable speedup in visualisation see graphics card documentation for information on OpenGL support Note that some cards only support OpenGL at a certain colour depth A number of graphics cards with 3D hardware rendering do not support all OpenGL features Users might thus experience problems with some of the WinFEKO features Setting the system colour depth to 256 colours forces software rendering with which OpenGL should not give any problems Alternatively one may rename the file OpenGL32_soft d11l in the bin subdirectory to OpenGL32 d11 to force software rendering at any colour depth 3 2 Running WinFEKO To run WinFEKO select Programs gt FEKO WinFEKO from the Windows Start menu if the FEKO shortcut has been installed in the default folder On startup Win FEKO tries to read a file winfeko ini from the user s home directory specified by the environment variable FEKO_USER_HOME This file contains information regarding the pre vious execution of WinFEKO e g which file was loaded the previous time WinFEKO was executed WinFEKO can be executed with a pre or wfp winfeko project file as command line parameter For example winfeko example_01 wfp or just winfeko example_01 In such a case WinFEKO will ignore the previous file information in the winfeko ini file and load the project example_01 wfp 3
14. 7 8 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7386e 001 8447e 001 9896e 001 0284e 001 9029e 001 9560e 001 8305e 001 8111e 001 7581e 001 7386e 001 71917e 001 8641e 001 8208e 001 8473e 001 7846e 001 71749e 001 8014e 001 8376e 001 8159e 001 8292e 001 7978e 001 8027e 001 8208e 001 8341e 001 8184e 001 8250e 001 Optimisation finished standard 2218e 000 2150e 000 1728e 000 1769e 000 2205e 000 2053e 000 2270e 000 2282e 000 2214e 000 2218e 000 2255e 000 2207e 000 2281e 000 2268e 000 2266e 000 2266e 000 2274e 000 2262e 000 2283e 000 2279e 000 2279e 000 2277e 000 2281e 000 2279e 000 2282e 000 2282e 000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 THE OPTIMISER OPTFEKO 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 dev small enough 5 773
15. As a rule of thumb it can be said that the radius of the inner conductor must be the same as the radius of the segment and that the outer radius should be 2 to 3 times the size of the inner If an impedance Z is desired then the following relation can be used EIR4 De 60 0 in O Se to determine the outer radius For Z 50 Q EIR4 should be equal to 2 3 EIR3 December 2002 FEKO User s Manual 9 14 DESCRIPTION OF THE CONTROL CARDS 9 2 7 A4 Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 NFU ULA EII3 EIR1 EIR2 EIR3 EIR4 EIR5 EIR6 EIR7 A IE REAL REAL REAL REAL REAL REAL REAL REAL This card creates a coaxial attachment feed approximation for use in connection with the Green s function for planar substrates with a metallic ground plane GF card sec tion 9 2 27 Parameters ANFL 0 New excitation replaces all previous excitations 1 Additional excitation add to previous excitations ULA The label of the triangle to excite The feed point is at the cen troid of the triangle see also figure 9 4 If there are more than one triangle with this label the excitation is placed on the one with the highest element number Alternatively the user may set ULA 1 and specify the Cartesian coordinates c EIR3 y EIR4 and z EIR5 of the feed point FEKO will then excite the triangle whose centroid is closest to the specified coordinate EII3 0 No correction of the impedance it is computed directly at the excitation point 1 Us
16. CableMod 9 20 9 46 CAD program configuring 3 10 3 32 capacitance loading 9 75 9 77 9 78 card editing 4 2 CB card 8 13 CG card 9 43 circular cone 8 50 circular disc 8 56 circular hole 8 73 CL card 8 14 clear model information 3 11 output data 3 11 3 23 close graph 5 3 close project 3 7 CM card 9 46 CN card 8 17 CO card 9 47 coarse segmentation 8 47 coating of wires 9 47 coaxial attachment approximation 9 14 coil 8 29 command line parameters WinFEKO 3 33 comments 8 3 9 4 cone 8 50 configuring parallel Windows version 3 12 connection points definition 2 4 continuous frequency plotting in GraphFEKO 5 16 contour plots near fields 3 18 control cards 2 1 9 1 94 AO 9 8 Al 9 11 A2 9 12 A3 9 13 A4 9 14 A5 9 16 A6 9 17 AT 9 19 AC 9 20 AE 9 23 Al 9 25 AP 9 27 AR 9 34 AV 9 39 BO 9 41 CG 9 43 CM 9 46 CO 9 47 DA 9 50 DI 9 52 EN 9 53 FE 9 54 FF 9 63 FR 9 65 GF 9 67 L4 9 74 LD 9 75 LE 9 76 LP 9 77 LS 9 78 LZ 9 79 OF 9 80 OS 9 81 PS 9 83 PW 9 85 SK 9 89 SP 9 93 TL 9 94 coordinates selection 3 4 copy geometry 8 92 project 3 8 coupling 9 93 transmission line 9 20 9 46 create project 3 3 1 2 cuboids 8 18 8 86 definition 2 4 display 3 25 current sources line segment 9 20 9 25 9 39 currents animation 3 21 calculation request 9 81 display 3 5 3 21 3 24 in GraphFEK
17. FEKO output file as command line parameter e g graphfeko exe example_01 out After selecting a file the filename with extension tmg appears in the information bar at the bottom left of the GraphFEKO window e g C FEKO examples example_02 tmg when the file example_02 out was selected GraphFEKO creates this temporary file by copying the out file to a tmg file in the same directory All subsequent file manipulations are done using the tmg file to avoid corruption of the out file December 2002 FEKO User s Manual 5 6 THE PROGRAM GRAPHFEKO 5 3 2 2 Clear Select this option to clear all data associated with the selected FEKO output file from GraphFEKO memory The selected file is also cleared i e anew FEKO output file must be selected before any further data extraction can be performed with GraphFEKO This is used when doing additional runs with the same file name 5 3 2 3 Antenna parameters When this item is selected GraphFEKO loads the antenna parameter data if it exists from the selected output file and opens the Antenna parameters panel The various frequencies at which the FEKO solution has been obtained are displayed in the Frequency box The Source nr field lists the voltage sources in the order they appear in the output file If a number of voltage sources are added before requesting output which requires a matrix solution the sources will each be given a number such that one may plot the input parameters for
18. IP 0 35 DP A 0 0 0 0 0 0 DP B 0 0 0 0 0 5 DP 1 0 0 0 0 0 DP D 0 5 0 0 0 5 KK A B Cc D 260 0 0 3 0 15 EG EN December 2002 FEKO User s Manual EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 53 Third example of KK card usage Oblique cones e g the rear part of an aircraft fuselage can also be produced The commands below generates the conical shell shown in figure 8 26 For a truncated cone the lines 51 53 and S2 S4 must be parallel The cross section is circular in planes that lies parallel to these lines and orthogonal to the plane containing all four points oblique cone IP DP DP DP DP KK gt oaw e oooo nw a OO OO a o gd EG EN Figure 8 26 Oblique example for the KK card December 2002 FEKO User s Manual 8 54 DESCRIPTION OF THE GEOMETRY CARDS Fourth example of KK card usage A cone section with an elliptical cross section as shown in figure 8 27 is generated with the following commands example for an elliptical cone ta 1 8 first half axis tb 1 0 second half axis hct 3 5 height of the cone rct a 2 radius of the whole at the top cylinder offs a 2 offset for the cylinder segmentation edge_1 0 4 IP edge_1 define points DP B 0 0 0 DP D a 0 0 DP E rct offs0 hct DP F offs 0 het define the geometry KK B F D E 360 edge_l edge_l 0 b a EG EN
19. If for example the user is specifying a BL card before the first DP card right clicking on the input fields will have no result December 2002 FEKO User s Manual THE PROGRAM GRAPHFEKO 5 1 5 The program GraphFEKO The program GraphFEKO has been developed as a separate executable but it is part of the Graphical User Interface GUI for FEKO in a MS Windows environment Tt is used for creating 2D plots of the calculation results 5 1 Running GraphFEKO To run GraphFEKO select GraphFEKO in the FEKO folder under the Windows Start menu It can also be executed with a out file as command line parameter for example graphfeko exe example_01 out In such a case GraphFEKO will load the data available in the given output file If GraphFEKO is executed from within WinFEKO the data in the output file of the current WinFEKO project will be loaded into GraphFEKO 5 2 Toolbars in GraphFEKO The toolbars in GraphFEKO can be organised into 2 main groups Most buttons on these toolbars are associated with menu items and their functionality will be described in the corresponding menu item sections 5 2 1 FILE control toolbar 1 2 3 OA 5 6 Used for GraphFEKO file control and printing The functions of the buttons are 1 Open a graph file see section 5 3 1 1 Save a graph file see section 5 3 1 2 Load data file see section 5 3 1 8 Save data file see section 5 3 1 9 Print graph see section 5 3 1 10 Print to fil
20. PS 0 0 1 0 Frequency FR 0 50 0 plane wave so that Hi 1 A m AO 0 L 1 zf0 0 0 180 0 0 0 0 0 Output the surface currents os 1 0 End EN Note the 1 in the fourth integer field of the EG card This activates LFFEKO which then requires an additional input file sphere geo reproduced below sphere The sphere is a closed solid For these structures the number of loops must be reduced otherwise the matrix will be singular DELLOOP 1 END December 2002 FEKO User s Manual 12 4 THE PROGRAM LFFEKO The following is an extract from the output file sphere out Special formulation for low frequencies 1 loop s has have been deleted Condition number of the matrix 3 85214E 03 VALUES OF THE CURRENT DENSITY VECTOR ON TRIANGLES in A m Triangle centre JX JY JZ number x y z magn phase magn phase magn phase 1 949 128 128 2 823E 01 180 00 3 315E 05 179 67 1 419E 00 00 2 949 128 128 2 823E 01 00 3 359E 05 33 1 419E 00 00 3 897 253 255 3 001E 01 00 8 287E 03 00 1 420E 00 00 4 897 253 255 3 001E 01 180 00 8 287E 03 180 00 1 420E 00 00 5 825 125 491 8 114E 01 00 1 138E 06 8 40 1 214E 00 00 6 825 125 491 8 114E 01 180 00 6 077E 07 164 10 1 214E 00 00 The surface current on the surface of the sphere is shown in the figure 12 1 It should be noted that this example can also be solved in the normal version of FEKO where symmetry can then be used Using LFFEKO the conditioning
21. R The weight of the control point when this point is used with the NU card NURBS surfaces When this field is empty the default is 1 In addition to its coordinates each point is also assigned the current label see LA card so that a group of points can be selected by label for example when moving points with the TP card In an exception to the rule that all geometry cards must appear before the EG card this card as well as the TP card can be used after the EG to define points for use in the AP card When defining or using node names simple variable names of the form A i are allowed The algorithm is that if a hash sign is found in a node point name this hash sign and everything that follows is interpreted as a variable string evaluated and rounded to the nearest integer Thus if we have k 15 and use or define a point P k then this is equivalent to using P15 as point name The length of the node name string before and after expansion is still limited to 5 characters For instance it would now be possible to define the points P1 to P20 inside a loop for k 1 to 20 DP P k Inext EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 21 8 2 11 DZ Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ry Ra R3 R4 R5 Re R7 Rg INT INT INT INT INT str istristristrispRl REAL REAL REAL REAL REAL REAL REAL REAL With this card a dielectric cylinder c
22. The parameters M Ng Ng and Np are all specified on the line that follows the key word RICHTDIAGRAMM or RADIATION_PATTERN M is a flag that has the following meaning Ey components used M 2 E components used Np is the number of the far field data blocks that are to be read and Ng indicates the number of rows that are to be read from each block i e the number of discrete points Vj pj when varying the angle Np gives the number of lines to follow with the definition of the aim radiation pattern This is followed by Np lines of the form N VALUE where N is an index and VALUE is the value of the normalised radiation pattern for this angle N N must be in the range 1 Ns and VALUE in the range 0 1 at it is a normalised quantity The aim function which is used by FEKO is computed as follows E9 0 0 vt LS Pon _ py B Ns 1 j A Dijes where P j is the user specified aim radiation pattern with j is in the range 1 Ns OPTFEKO automatically uses a linear interpolation for points in between the Np spec ified points Should P 1 not be defined by the user OPTFEKO assumes P 1 0 Es p 05 p is the electric field strength the component which is selected by M for the j far field line in the 1 block E ax represents the maximum field str ength amplitude the component which is selected by M in the it far field block i e Ef maxj Es V p which is required to max normalise the field stre
23. With this card the application of the physical optics approximation is possible Parameters POLAB NOSHADE POSYMFLAG December 2002 All metallic dielectric triangles and polygons that have the label POLAB are treated with the physical optics approxima tion 0 Normal ray tracing is carried out 1 The ray tracing is switched off to save computational time The assumption is made that all triangles on which the PO approximation is made are illuminated by the source and the moment method area The side in relation to the normal vector is automatically determined 2 Full ray tracing is done as for NOSHADE 0 but metallic triangles can only be lit from the side to which the normal vector is pointing This has two applications e Acceleration of the PO ray tracing with closed bodies the normal vector must then point outward since the dot product of the normal and propagation vectors can be used to quickly determine if a triangle or polygon is to be used in the ray tracing In this case the closed model must be constructed with the normals pointing outward e In for example the MoM PO hybrid method on a closed body the MoM region such as an antenna can be pre vented from illuminating the PO region from inside If ray tracing is done with NOSHADE 0 then symmetry is used Thus the computational time is reduced when determin ing the shading For electric and magnetic walls it is assumed that symmetrical shading is pos
24. lez phase e3 lhiij Phase hijsj Roug phase hoz h3 j phase h3 i all in one line EM Software amp Systems S A Pty Ltd December 2002 THE OPTIMISER OPTFEKO 10 15 Of course this general case with M 3 includes the cases that one optimises only for the electric or only for the magnetic field one can just set all the factors fe to zero for instance and would then optimise only for the magnetic field But the format of the table will then still require the specification of in this case arbitrary field values also for e whereas when using M 2 the format of the table of the required field strength values is simpler and includes only the desired normalised magnetic near field h 10 4 Running OPTFEKO Firstly the pre and opt files must be created as discussed above During optimisation new pre input files are continuously created by adding the string _opt_ and a sequen tially incremented number to the file name When for example the files dipole pre and dipole opt have been created OPTFEKO is run with the command optfeko dipole On the command line the following parameters can be added r The pre and out are deleted after each analysis This saves disk space R Same as r but the files of the optimum solution are kept Z The value of the aim function is calculated for one existing file no optimisation is done This is mostly used for debugging np x If this option is given the par
25. not delete the 3D far field display Near field When selected the near field ortho slices and iso surfaces obtained from the FEKO output file are displayed if the near field data has already been loaded Unselect this option to hide not delete the near field display Infinite plane When selected the infinite plane s associated with the current project is displayed This could be the ground plane as defined using the BO card or the ground plane and or infinite layers associated with the Multilayered substrates GF card EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 25 e Request fields When selected the requested fields as specified with the FE and FF cards in the pre file are displayed if the request field data has already been loaded Unselect this option to hide not delete the requested fields display e Transmis lines If the model contains TL cards they are displayed by checking this field The lines are drawn in yellow between the segments they are connected to The lines are not drawn from the centres where they are physically connected such that one can determine the polarity of the connection Under Wire segments select e Lines Display segments as lines e Surface Display segments as tubes Unselect this when the model has a large number of line segments to avoid slow rendering especially when printing to vector formats Under Triangles select e Lines Outlines of
26. of coupling for PO Fock 0 000 Calcul of matrix A 0 031 Calcul of vector Y right side 0 000 Solution of the linear set of eqns 0 016 Determination of surface currents 0 000 Calcul of losses 0 000 Calcul of electric near field 0 000 Calcul of magnetic near field 0 000 Calcul of far field 0 031 other 0 000 total times 0 109 EM Software amp Systems S A Pty Ltd magnitude ar in dB E 02 35 16 E 01 0 69 E 01 9 06 ONDS DESCRIPTION OF THE OUTPUT FILE OF FEKO phase in deg 94 33 6 73 7 33 in seconds time December 2002 Index card 8 3 9 4 2D plots far fields 3 14 near fields 3 16 3D patterns 3 15 display 3 24 AO card 9 8 Al card 9 11 A2 card 9 12 A3 card 9 13 A4 card 9 14 A5 card 9 16 A6 card 9 17 A7 card 9 19 AC card 9 20 ADAPTFEKO 13 1 plotting in GraphFEKO 5 16 adaptive frequency sampling 13 1 add lines in GraphF EKO 5 19 advanced visibility 3 28 AE card 9 23 AI card 9 25 animation currents 3 21 near fields 3 20 anisotropic layers 9 89 display in WinFEKO 3 25 antenna parameters 3 5 3 13 5 6 display in GraphFEKO 5 2 AP card 9 27 aperture 9 27 AR card 9 34 array sizes 2 12 2 13 AV card 9 39 axial ratio plotting in GraphFEKO 5 12 axis display 3 23 length setting of 3 31 BL card 8 4 BO card 9 41 IL 1 border curved PO edge 8 14 PO correction edge 8 49 PO correction wedge 8 55 BP card 8 6 BQ card 8 8 BT card 8 11
27. phase ley phase lezl phase NEARFIELD_VALUES 1 1 5 3 3 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 0 875 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 875 0 0 0 0 0 0 0 0 0 0 0 5 0 0 If one wants to enforce to have only E but no E and E components then all one has to do is to change the two factors f and f2 which here in a Cartesian coordinate system refer to the x and y components both to 1 0 so that these components are included in the aim function One can also optimise both electric and magnetic near fields simultaneously then the syntax differs The first line still has the keyword NAHFELD_WERTE or NEARFIELD_VALUES After this we have a line M Np Ns Nnorm Ne comp Nh comp fea fe fe 3 Fr fn fn where the flag M must now be M 3 Use both the electric and magnetic near field The meaning of Ng Ng and Nnorm is still the same as when optimising only E or H but for the component Neomp one can now specify this separately for the electric and magnetic field using Ne comp Or Nh comp respectively There appear now also 6 factors f in this line they are used in the aim function Ng Ns 1 Z eN SS fea lexis eiil fez lezij eil Jes lesi e3451 i 1 j l n1 haag AU fro lhoeg ASTGI fas la AST 7 The table with the required field strength values has now also both E and H field values in one line the syntax is to have 12 columns le1ij phase e1 3 e2 j phase e2 5
28. tory FEKO_HOME mpi doc should be considered These are added after the argument mpi options For example on the ScaMPI cluster assuming FEKO_WHICH_MPI 6 the call runfeko example_08 np 6 mpi options immediate_handling threaded smtrace 5 6 all on one line is interpreted internally and FEKO is executed with the command opt scali bin mpimon export env immediate_handling threaded smtrace 5 6 opt feko bin feko csv example_08 hosti 4 host2 2 Note that host1 and host2 are examples only the actual information is taken from the machines file December 2002 FEKO User s Manual DESCRIPTION OF THE GEOMETRY CARDS 8 1 8 Description of the geometry cards 8 1 Overview of the geometry cards The following table lists all input cards that are used to create the geometry i e the cards that appear before the EG card in the pre file Most of these cards are processed by PREFEKO For example PREFEKO processes the BP card and writes the triangle elements to the fek file as input to FEKO Card kx BL BP BQ BT CB CL CN DK DP DZ EG EL FO HE IN IP KA KK KL KR KU LA ME NU PB PH PM PO Description characters used to indicate a comment creates a line creates a parallelogram creates a quadrangle creates a triangle changes already assigned labels creates a circular line using segments change the direction of the normal vector dielectric or magnetic eighth of a sphere define a
29. 0 0000E 00 1 0000E 00 2 0000E 02 In this case an additional line gives the components nx ny nz of the normal vector of each triangle EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE OUTPUT FILE OF FEKO 14 3 For the edges the extract is DATA OF THE DIELECTRIC EDGES with MoM triangle no points of the triangle no type length m media KORP KORM POIP POIM POIA POIE 1 3 2 8284E 01 0 1 1 2 1 1 3 2 2 3 2 0000E 01 0 1 1 3 2 3 1 3 3 3 2 0000E 01 0 1 1 26 3 3 1 2 electr info of symmetry magnet info of symmetry yz XZ xy status yz XZ xy status 0 0 42 unknown 0 0 42 unknown 0 0 43 unknown 0 0 43 unknown 0 0 44 unknown 0 0 44 unknown In addition to the data that is given for the metallic triangles the following columns are provided POIA POIE KNP and KNM The column POIA contains the number of the corner point of the triangle in KORP where the basis function for magnetic surface current begins and the column POIM contains the number of the end point of the triangle where the basis function ends The sizes KNP and KNM are the lengths when the vertices are connected to the middle of the opposite edge in the triangles KORP and KORM The symmetry informa tion is shown for the basis functions of both the equivalent electric or magnetic current densities The data for the segments follows the data for the triangles DATA OF THE SEGMENTS No label xl inm yi inm z inm nodes medium x2 inm y2 inm z2 inm
30. 0 8 0 9 1 h lambda Figure 13 4 Input admittance of a forked monopole derived by multiplying the admit tance of a forked dipole by a factor of 2 December 2002 FEKO User s Manual DESCRIPTION OF THE OUTPUT FILE OF FEKO 14 1 14 Description of the output file of FEKO The program FEKO writes all the results to an output file out In this section the parts of the output file are described 14 1 Geometric data First the geometric data is given if it has not been suppressed by the PS1 parameter in the EG card For the metallic triangles the following extract is written DATA OF THE METALLIC TRIANGLES no Label xl inm yi inm z inm edges medium x2 in m y2 inm z2 inm x3 inm y3 inm z3 inm area in m m 1 0 1 2733 0000 0000 1 2 0 1 9100 0000 0000 1 7646 7309 0000 2 3268E 01 2 0 1 1027 6367 0000 1 3 4 0 1 2733 0000 0000 1 7646 7309 0000 2 1874E 01 In the first column the number of the triangle is written In the second column the label is given followed by the medium in which the triangle is situated A 0 means that it is in free space The next three columns are the x y and z coordinates of the three corner points of the triangles In the first row of each triangle follows another list of the numbers of the edges of the adjacent triangles A positive sign indicates that the positive current direction is away from the triangle A negative sign indicates that the positive current direction is towards the triang
31. 2 12 for a discussion of the allowed configurations Alternatively the edge can be along a connection between triangles and a polygonal UTD plate or a PEC ground plane or it can be a microstrip feed line port The impedance Z applies to the complete edge i e all the single edges in parallel The LE card can be combined with the AE card to specify both an impedance and a voltage source over the edge Parameters I Iz The meaning of these parameters depends on J3 I3 0 Load the edge between the regions with labels J and Iz with a complex impedance 2 Load the edges of metallic triangles with label J which are connected to UTD surfaces or to a PEC ground plane as specified with a BO or GF card Jp is not used 3 Special microstrip line port load The load is placed on all edges on the line between points previously specified with DP cards J and J2 A GF card with a conducting ground plane must be present R Real part of the complex load impedance X Imaginary part of the complex load impedance Note that the edge between triangles with labels J and Jz does not need to be straight One may for example specify a resistive connection between two half cylinders oad impedance R jxX Figure 9 26 Application of the LE card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 77 9 2 31 LP Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 Pl LAB RP LP GP INT NT R EAR NT REA
32. 3 1 1 1 EG EN Figure 8 11 Example of a BT card with inhomogeneous segmentation EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 13 8 2 6 CB Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 Ty I2 R ae aes NT NT REAL REAL REAL REAL REAL REAL REAL REAL This card is used to change or reassign the labels assigned to points segments triangles cuboids polygons tetrahedral elements etc This is especially useful when more labels are created by using symmetry SY card or transformation TG card and for example edges or wedges in the PO area are considered Parameters I Old label I New label All structures with the label created and or imported before processing the CB card are assigned the new label 2 Structures created after the CB card are not affected December 2002 FEKO User s Manual 8 14 DESCRIPTION OF THE GEOMETRY CARDS 8 2 7 CL Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ry Ra R3 Ra R5 T R R NT NT REAL REAL REAL REAL REAL REAL REAL REAL This card can create an arc consisting of segments Alternatively this card may be used to create an arc which forms the border to the PO region See figure 8 12 S Figure 8 12 Sketch illustrating the use of the CL card Parameters S Name of the centre of the circle S Name of the point perpendicular to the plane in which the circle lies and above its centre S3 Name
33. 3 Hot keys in WinFEKO WinFEKO uses certain key combinations or hot keys to allow faster access to functions that are used often Some of these keys are always active but most are only active when the Main display options panel is open i e when no results or selection panel is shown The following keyboard keys are available as hot keys in WinFEKO Always active lt F2 gt Save Project lt F3 gt Open Project i Return to Main display options panel lt Alt gt lt 1 gt Run FEMAP lt Alt gt lt 3 gt Display neutral file EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 3 Only active with Main display options panel visible lt 1 gt Run EditFEKO lt 2 gt Run PREFEKO lt 3 gt Display FEK model lt 4 gt Run FEKO solver lt 5 gt Load and display output file lt 6 gt Start GraphFEKO lt U gt Rotate model up lt B gt Rotate model down lt L gt Rotate model left lt R gt Rotate model right lt A gt Toggle axes lt E gt Toggle DP label display lt N gt Toggle element number display lt S gt Toggle label number display lt O gt Toggle element normal display lt V gt Toggle hidden line removal lt gt Zoom in on the numerical keypad only lt gt Zoom out on the numerical keypad only Arrow R Pan right Arrow L Pan left Arrow U Pan up Arrow D Pan down 3 4 Toolbars in WinFEKO The toolbars in WinFEKO can be organised into 5 main groups Most of the speed buttons on
34. 5 at Da ee Gs bak a e E D 9 54 A 6 ogi Gat IEA 9 63 epee ELTA sic ca we dee ede ate ead 9 65 a eo Se ek Oe ee ee ee eee 9 67 A Card a gig eee AR Re a le ee e a a eS 9 74 OA LOC a oe BAe we ee ee RA het ee ws 9 75 et a A Ek oh he 9 76 Dadl LF AA o eaaa a a RS he Se 9 77 Oe DO Ca e G8 Gb oS ik dee ob wea Oe ani be ad 9 78 AN ig ee ee Re Bs Oe ee ee ee 9 79 Oe MIN CREE sis OE OS FG io oe Oe Pa wo Ge am 9 80 Deo LO EAP oo Te Geter a ae ae ed Gee a we ap ee aS 9 81 One Po Oe 6 oS oa te ee AS Ea eRe eS 9 83 ALO OW AO oo aa Rhee ee Da Pe wwe x 9 85 Deo MEMOS ak bad ea bpp ages aed a ae tle at E 9 89 De E A oe EE ee ee ee eee 9 93 92 90 TLUI oia i a a o aaa aae m atab A a eee ed 9 94 EM Software amp Systems S A Pty Ltd December 2002 CONTENTS vii 10 The optimiser OPTFEKO 10 1 MOT nto s L e II 10 1 10 2 This pre tpt ie o a a a po Re S 10 1 M The opt npu fle scoct ee eR heheh GOSH Gs 10 1 10 3 1 Definition of optimisation parameters 10 2 10 3 2 Definition of the penalty function 000 10 2 10 3 3 Definition of the optimisation process 10 3 10 3 4 Defining the aim function 10 5 104 Rune OPTFEKO 082 ee eee ee ee eR EEE ews 10 15 10 5 An example using OPTFEKO e 10 15 11 The program TIMEFEKO 11 1 ULT DISCO UOR 2 2 6 ccc iia ae a A 11 1 11 2 The pre inputll e 0 0 oc2n o 0 0 11 1 11 4 The tim input file ee a
35. 6 another 2 lines analogous to this one have to be defined for the first layer in the middle and for the core The scaling factor that is entered by the SF card is applied to the radius The parameters of the medium outside the sphere usually free space can be set with the EG card The Green s function for a homogeneous or layered dielectric sphere can be used with metallic structures treated with the MoM either inside or outside the sphere but not for example a wire from inside to outside It can be used with dielectric bodies treated with the volume equivalence principle e g the hand of a user around a mobile phone but the dielectric bodies must be outside the sphere An example of the use of the GF card for a sphere is given in example_15 Examples Guide EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 71 e Planar Multilayer Substrate GFFLAG 10 11 12 13 Zz Figure 9 25 Example of a 4 layer substrate with a metallic ground plane Parameters GFFLAG 10 Green s function for planar layered media with a metallic ground plane at the bottom of layer Jy the top layer 0 extends to z 00 Metallic structures or field compu tations are only supported above the ground plane The ground plane is assumed to be infinitely large a finite ground plane can be modelled directly in FEKO using tri angular patches 11 Layered dielectric media without metallic ground pl
36. 90 100 110 S S2 S3 Sa Ra Ra mo ae aes mT NT REAL REAL REAL REAL REAL REAL REAL REAL This cards creates a triangular or quadrangular plate with a circular or elliptical hole as shown in figure 8 41 The hole can be used for example to attach a cylinder ZY card to the plate and it can be filled with the KR card Figure 8 41 Sketch illustrating the use of the PH card Parameters S Name ofthe corner point where the hole is located it is also the centre of the hole Sz Name of the second corner of the plate S3 Name of the third corner of the plate If this field is left empty a triangular plate is created Sa Name of the fourth corner of the plate Ss Name of a point on the line S S2 that forms the starting point of the circle or ellipse bordering the hole The special case where Ss is identical to S2 is supported but due to the resulting geometry yields triangles with very small angles R The maximum edge length of the triangles along the edge of the hole in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used Ra If this parameter is empty or is set to 1 a circular hole is created Within certain limits the parameter R4 may be used to generate an elliptical hole R4 where a is the distance S1 S5 then gives the ratio of the two half axes of the ellipse December 2002 FEKO User s Manual 8 74 DESCRIPTION OF THE GEOMETRY CARDS First example of
37. A3 Excitation by means of a magnetic ring current TEM Frill on a segment Thus a coaxial feed can be modelled A4 Special vertical pin excitation e g for a patch antenna on a planar substrate with a ground plane coaxial probe excitation mode A5 A Hertzian dipole is used as excitation The position and orien tation in the space are arbitrary A6 A Magnetic dipole is used as excitation The position and orien tation in the space are arbitrary A7 Excitation by means of a voltage gap on an edge between two triangles AC This card reads the geometry and current distribution possibly for more than one frequency from an rsd file created by the transmission line simulation program CableMod or with the OS card in FEKO The excitation is due to the electromagnetic fields radiated by these line currents AE The AE card is an excitation between triangle edges similar to the AT card however the AE card permits the simultaneous excitation of several edges AI Excitation by an impressed line current AP Excitation with an aperture array of electrical and magnetic Hertzian dipoles AR Excitation by an antenna with a given radiation pattern AV Excitation by an impressed line current similar to the AI card but the endpoint of the current is electrically connected to a con ducting surface The different ways to realise a voltage source are summarised in figures 9 1 and 9 2 The impressed electric field strength is indicated by E
38. Cartesian components With phase selected the phase in degrees of any one of the three Cartesian components is displayed e g phase E With instantaneous selected the real field vector is calculated as Elt Re E x e t and the iso surface quantity 3 20 280 is displayed or any combination of the three components depending on the choice of Cartesian components With H_field the same applies as with E field With S as quantity the time averaged Pointing vector is calculated as S 1Re E x H 3 With mag selected Sz Sy S is plotted or any combination of the three components depending on the choice of Cartesian components With phase selected the phase of Ex H in degrees of any one of the three Cartesian components is displayed With instantaneous selected the real instantaneous power density is calculated as a t E t x h t and the iso surface quantity 4 s2 t s2 t s2 t is displayed or any combination of the three components depending on the choice of Cartesian components Select Linear or dB scaling under the Scaling options Min minimum and Maz max imum slide bars and edit boxes are available to clip the limits of the data In the case of iso surface display these clipping slide bars only change the colour of the iso surface Also under Scaling is the wt option By default wt 0 is selected With instantaneous selected under Component wt will become enabled and the required
39. DESCRIPTION OF THE CONTROL CARDS 9 2 21 DA Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 DA DA DA DA DA DA EFE HFE FFE OS CGM SNP IE REAL REAL REAL REAL REAL REAL REAL REAL With this card some data like near fields or S parameters can be exported to additional ASCII files The card allows to switch this export on and off and affects only cards for the computation of for example near fields or S parameters that follow the DA card By default all export is off Parameters DAEFE 1 The electric field strength is stored in a efe file 0 The efe file is not stored DAHFE 1 The magnetic field strength is stored in a hfe file 0 The hfe file is not stored DAFFE 1 The far field is stored in a ffe file 0 The ffe file is not stored DAOS 1 The currents are stored in a os file 0 The os file is not stored DACGM 1 The residue from the iterative algorithm used to solve the matrix equation is stored in a cgm file o The cgm file is not stored DASNP 1 The S parameters are written to a file in Touchstone SnP format The n here gives the number of ports 0 The SnP file is not stored The exact description of the files can be found in section 2 2 More than one DA card is allowed in one input file Thus using the following control card sequence DA 1 FE 1 DA 0 FE 1 the electric fields calculated with the first FE card are written to the efe file but not those of the sec
40. DOLALAB LAB XOFFSET YOFFSET ZOFFSET LAG BEL MIN MAX TR ae aay NT NT REAL REAL REAL REAL REAL REAL REAL REAL This card specifies an offset for the origin of the coordinate system used for near and far field calculations In addition it is possible to use only a part of the structure when calculating the fields selected using labels Parameters OFFLAG 0 No coordinate transformation the fields are calculated in global coordinates 1 Use the offset specified below as the origin of the coordinate system for field calculations DOLABEL 0 All structures are used in the field calculation 1 Use label selection when calculating near and far fields Only the currents on structures with a label in the range LABMIN LABMAX are used during field computation If a basis function extends over for example two triangles it is included if either triangle lies in the specified range LABMIN Label range see parameter DOLABEL LABMAX Label range see parameter DOLABEL XOFFSET vz coordinate of the transformed origin in m it is scaled by the SF card if SKALFLAG 1 YOFFSET y coordinate of the transformed origin in m it is scaled by the SF card if SKALFLAG 1 ZOFFSET z coordinate of the transformed origin in m it is scaled by the SF card if SKALFLAG 1 A possible application of the OF card is for example to calculate the near field on the surface of a sphere whose centre does not lie on the origin The OF card transforms the origin
41. FEKO The current on the segments is written as VALUES OF THE CURRENT IN THE SEGMENTS in A Segment centre IX number x m y m z m magn phase 1 2 25000E 00 0 00000E 00 6 67500E 01 0 000E 00 0 00 2 25000E 00 0 00000E 00 5 02500E 01 0 000E 00 0 00 3 2 25000E 00 0 00000E 00 3 37500E 01 0 000E 00 0 00 IY IZ magn phase magn phase 0 000E 00 0 00 2 208E 03 145 51 0 000E 00 0 00 6 118E 03 146 21 0 000E 00 0 00 9 000E 03 147 38 With the associated charge VALUES OF THE LINE CHARGE DENSITY ON SEGMENTS in As m Segment Q number magn phase 1 4 26233E 11 55 51 2 3 28910E 11 58 02 3 2 28537E 11 62 48 For every voltage source the current at the feed point is determined and thus the impedance The following is the result DATA OF THE VOLTAGE SOURCE NO 1 real part imag part magn phase Current in A 1 0888E 02 4 4405E 03 1 1759E 02 22 19 Admitt in A V 1 0888E 02 4 4405E 03 1 1759E 02 22 19 Impedance in Ohm 7 8747E 01 3 2116E 01 8 5044E 01 22 19 Power in Watt 5 44395E 03 EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE OUTPUT FILE OF FEKO 14 11 14 4 Finite conductivity Firstly the block with the set of characteristics for the single labels is displayed DATA OF LABELS Label 2 DOSKIN 3 DOLAST 0 Triangle thickness 5 00000E 03 m Sigma 1 000E 05 S m Mue_r 1 000E 00 Penetration depth of the skin effect 1 59210E 04 m All segments and triangles without a listed label are perfectly
42. FEKO User s Manual 8 94 DESCRIPTION OF THE GEOMETRY CARDS triangle is transformed to a new point Lp T As yr Y1M y 7 4A r 2 A with the rotation matrix COS Qy COS Qz COS Qy Sin Az sin Qy M cosaz sin amp z sin az sin Qy COS Az COS Qg COS Qz SIN Qg SIN Qy Sin az sin Qg COS Qy sin Qg Sin Az COS Mz SIN Qy COS Az sin Gz COS Qz COS Qg SIN Qy Sin Qz COS Qg COS Qy Multiplication by the rotation matrix M effectively rotates a point first by an angle a around the z axis then by an angle a around the y axis and finally by an angle a around x axis If more than one copy is made successive points are generated from the previous point using the same relation The file example_18 pre see the Examples Guide gives an example of an application of the TG card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 95 8 2 36 TO Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ry Ra R3 Ra R5 Re T ae ey NT NT REAL REAL REAL REAL REAL REAL REAL REAL Using this card a toroidal segment can be generated Figure 8 53 shows a sketch S Figure 8 53 Sketch illustrating the use of the TO card Parameters S Name of the centre of the toroid S2 The name of a point that is perpendicular and is situated an arbitrary distance above S which is in the plane of the toroid S3 The name of the point that represents the axis see figure 8 53 S4 A
43. For such models one might uncheck Display arrows to view these sources as short lines only December 2002 FEKO User s Manual THE PROGRAM WINFEKO Rendering Under Dynamic rendering select Render surfaces to render all surfaces when actively rotating translating zooming etc models If this is not selected the model will be displayed correctly but only representative lines will be visible when the model is manoeuvred For medium and large sized problems it is best to unselect the Rendering surfaces option Saving Under Project saving select Prompt on close to ensure that the user is warned when the project information has not been saved to the wfp file Remem ber it is not critical to save a project in WinFEKO because the wfp file do NOT contain the critical information associated with the FEKO input file pre file Select Window settings to have WinFEKO startup with the same window size width height as the previous time the program was run If not selected WinFEKO will start with the default size window which is slightly smaller than the users screen size Reading Under Out file reading select Report warnings to have WinFEKO report any WARNINGS present in the out file when the result data is loaded Read DP cards can be unchecked on slow machines for models which contain a large number of DP cards This may speed up the reading of the fek file but it is no longer as critical as with the older versions o
44. GFFLAG 1 Ri Ra R3 R4 Re R7 Sphere s radius in m is scaled by the SF card Relative dielectric constant p Relative permeability ur Conductivity o in y Electric loss factor tan an alternative to the conductivity o the two loss terms are related by tan ee Magnetic loss factor tan the complex permeability is then given by 4 Hokr 1 jtand for GFFLAG 2 Ri Ra R3 Ra Re R7 Sphere s radius core including the coating in m is scaled by the SF card Relative dielectric constant e of the coating Relative permeability jz of the coating Conductivity in ma of the coating Electric loss factor tan of the coating an alternative to the conductivity a the loss terms are related by tan a Magnetic loss factor tan of the coating the complex perme ability is then given by p or 1 j tand for GFFLAG 2 another line is specified as follows Ri Ra R3 Ra Re R7 Radius of the core in m is scaled by the SF card Relative dielectric constant e of the core Relative permeability ur of the core Conductivity o in of the core Electric loss factor tan of the core Magnetic loss factor tan 6 of the core for GFFLAG 4 Ri Ra Rs Ra Re R7 Sphere s radius including the outermost layer in m is scaled by the SF card Relative dielectric constant e of the third outer layer Relative permeability ur of the thi
45. J to I5 when read with PREFEKO these input fields may also contain strings such as node names containing five digits each and eight real parameters R to Rg containing ten digits each When entering the data into the cards the user must ensure that all parameters are entered in the correct columns The editor EditFEKO assists the user to place the parameters in the correct columns through the use of dialog boxes All parameters are in SI units e g lengths are in metres potential in volts etc Note the angles are in degrees FEKO includes various scaling options see the SF TG and IN cards such that dimensions may be entered in different units and scaled to metres The first line of the input file must contain the filename without extension The full filename including the path can be up to 254 characters long This specifies the file name to which different extensions are added for various output files see section 2 2 Alternatively the first line can be a comment card or empty line The principal structure of the input file is shown below xx Comments at the start of the input file Cards that define the geometry EG End of the geometry control cards that define the excitation and indicate which field quantities are to be calculated EN End of the input file Chapter 8 gives an overview of the geometric cards with detailed descriptions of the individual cards Similarly Chapter 9 gives an overview and descriptions
46. P3 P4 Half of the wire 0 Pi P2 P2 P3 Symmetry 1 0 0 1 The feed segment 1 P2 P4 End of geometry 1 0 0 0 0 Excitation 0 1 Adaptive frequency band 100 2 1lam 1000 lam 20 0 01 0 0 0 5 0 0 0 0 0 01 0 01 0 0 0 466 0 0 0 0 0 01 1 0 100 0e6 0 1e6 300 0e6 EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM ADAPTFEKO 13 3 Just compute the impedance OS 0 End EN l li li Figure 13 1 Forked dipole used in the ADAPTFEKO example Note that we do not use adaptive meshing as the model is quite small This avoids the trouble associated with small discontinuities resulting from changes in the mesh After running ADAPTFEKO we have the file forked_dipole out which is a combi nation of the output files at the sample frequencies In addition we have the file forked_dipole afo which contains the continuous frequency data in a format which can be used by GraphFEKO The file forked_dipole bof is a binary output file which will be used in a future release of FEKO If the solution is done on a workstation both the out and afo files must be copied to the PC where the post processing is done To display the results in GraphFEKO import the out file If the afo file is available in the same directory the ADAPTFEKO results button and the Import ADAPTFEKO results menu item become enabled Selecting either of these opens the ADAPTFEKO results panel in GraphFEKO All parameters for wh
47. PH card usage The commands below create the rectangular plate shown in figure 8 42 Note the ex tremely narrow triangles at the corners as mentioned above Example for the PH card Size of the plate ta 1 Hb 1 Size of the circular hole hole 1 xx Discretisation ttedge_1 ta 10 IP ttedge_1 Define the points DP A 0 0 0 DP B a 0 0 DP C a b 0 DP D 0 b 0 DP E hole 0 0 The plate with hole PH A B C D E ttedge_1 EG EN Figure 8 42 Example using the PH card EM Software 4 Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 75 Second example of PH card usage Figure 8 43 shows a rectangular plate attached to an elliptical cylinder created with these commands Example of attaching the PH card to a cylinder Size of the plate ta 1 2 tb 1 7 Size of the elliptical cylinder ttella 0 7 ellb 0 3 h 0 3 ratio ellb ella Discretisation ttedge_1 ta 10 edge_ld 0 8 edge_1l IP edge_1 Define the points DP A 0 0 0 DP B a 0 0 DP C tta b 0 DP D 0 b 0 DP E ttella 0 0 DP F 0 0 h The plate with hole PH A B C D E edge_ld ratio The cylinder ZY A F E 0 90 edge_ld ratio EG EN December 2002 FEKO User s Manual 8 76 DESCRIPTION OF THE GEOMETRY CARDS Figure 8 43 Example of attaching a plate PH card and cylinder second example of PH card usage Third example of PH card usage
48. POLARISATION axial r angle direction 0 0000 180 00 LINEAR 0 0000 180 00 LINEAR 0 0000 180 00 LINEAR Gain is a factor of 1 00000E 00 0 00 dB larger than directivity The directivity gain is based on an active power of 4 88015E 03 W and on a power loss of 0 00000E 00 W The values that are displayed here are the values of the scattered field i e the incident field is not taken into account The Y and y components of Efay are tabulated Here we have e7 iboR lim F E RS P R jar and R F Please note that the dimension of Etar is voltage If the excitation is an incident wave the results include the radar cross section In the case of voltage sources the gain or directivity are included see the parameters of the FF card The gain directivity output is split into vertical 9 and horizontal p components The last three columns give the polarisation information of the scattered wave In general the polarisation is elliptical as shown in figure 14 1 The coordinates are y and and the view is in the direction of the propagation of the wave In the column axial the ratio between pain of the major and minor axes is given A ratio of 0 means that the wave is a linearly polarised wave but if the ratio has a value of 1 then it is a circularly polarised wave In the column angle the angle a is given It is the angle between the major axis and the unit vector ey The last column gives the direction
49. REAL With this card a cylindrical segment can be generated A sketch is shown in figure 8 61 C D on Figure 8 61 Sketch illustrating the use of the ZY card Parameters S Name of the begin point of the axis S2 Name of the end point of the axis S3 Name of a point on the corner of the cylindrical segment S4 0 The normal vector of the triangles points outward away from the cylinder 1 The normal vector points to the inside Ri The angle y in degrees which is subtended by the cylindrical arc R Maximum edge length of the triangles along the curved side in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 109 R3 If this parameter is empty or is set to 1 a circular cylinder is created Within certain limits the parameter Rg may be used to generate an elliptical cylinder R3 2 gives the ratio of the two half axes where a is the distance S S3 It is recommended to generate elliptical cylinders with extremely small or extremely large axial ratios with a CAD system such as FEMAP as the distortion formulation used in PREFEKO may fail in these cases The segmented area shaded in figure 8 61 is obtained by rotating the point S3 around the axis S1 52 through the angle yw For y 360 a full cylinder is obtained The fineness of the mesh on the sides parallel t
50. TA ae ey NT NT REAL REAL REAL REAL REAL REAL REAL REAL With this card the shell of a cone or conical section may be created The cone can also be distorted to have an elliptical cross section A sketch is shown in figure 8 23 a S b S S S ar a 3 Figure 8 23 Sketch of the use of the KK card a cone and b conical section Parameters S The name of a point on the axis of the cone in the plane of the base or the larger circular side for a conical section S2 The name of a point indicating the vertex of the cone This is the point in the plane of the smaller circle when creating a conical section S3 The name of a point on the radius of the base S4 If this parameter is defined then a conical section is generated if not then a cone is generated S4 is the point on the radius of the smaller circle and must be in the plane given by Si S2 and S3 Ri The angle yg in degrees subtended by the conical section R Maximum edge length of the triangles along the arc of the cone or the larger arc of the conical section in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used R3 Only applies for conical sections the maximum edges length of the triangles along the smaller of the arcs in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION
51. Variables and functions may be used in the expression for the scaling factor for example IN 1 filename neu scaling 3 5 IN 4 filename dxf 7 scaling my_scal IN 3 1 filename nas scaling 1 0 0 2 x_var sin 0 71 It should be noted that the scaling factor specified with the IN card is applied in addition to any scaling factor that may be set with the SF or TG cards When reading a pre file FLAG 0 it is not possible to add a scaling factor to the IN card In this case the TG card must be used if the global SF card scaling option is not sufficient The parameter FLAG determines the type of file e FLAG 0 Read a pre file This allows large pre files to be split into several parts It is for example particularly useful when the same geometry is used in different files The syntax is IN 0 head pre IN 0 body pre and no other parameters are supported The cards in the included files are processed as if they were part of the main file Therefore points and labels defined in the included file remain valid in the remainder of the main file Note that the file must have the syntax of a pre file but the extension can be arbitrary It is suggested to use for example inc for include to clearly distinguish between main pre files that are input for FEKO and include files EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 33 e FLAG 1 Read a neu FEMAP neutral
52. When using the FF card with NTHETA gt 2 and NPHI gt 2 then the Poynting vector is integrated over the two spherical segments e Jo 4 Ad lt V lt Yo NTHETA Ad and yo 4 Ay lt p lt po NPHI 4 AV e Vo lt V lt Vo NTHETA 1 AY and po lt lt yo NPHI 1 Ap If only the integrated power is of concern the option FFREQ 3 may be used to reduce the size of the output file In the case of an antenna the power provided by the voltage sources must be equal to the radiated power over the whole sphere The total radiated power can be calculated using for instance the following commands xx Far field integration in angular increments of delta in degrees delta 5 nt 180 delta 1 np 360 delta 1 FF 3 nt np 0 0 0 delta delta The output in the out file then reads for example Integration of the normal component of the Poynting vector in the angular grid DTHETA 5 00 deg and DPHI 5 00 deg 2701 sample points angular range THETA angular range PHI radiated power 2 50 182 50 deg 2 50 362 50 deg 5 60499E 03 Watt 0 00 180 00 deg 0 00 360 00 deg 5 52821E 03 Watt If the problem is symmetrical it is not necessary to carry out the integration over the complete sphere If there are three planes of symmetry as for a simple dipole in free space the integration only needs to be done over an eighth of the sphere The power then has to multiplied by 8 If
53. a a 11 2 114 1 Defining the pulse form lt a cosaid ro ree a a as 11 2 11 3 2 Definition of the frequency block 11 6 11 3 3 Definitions of the normalisation 11 7 11 3 4 Definition of the excitation output 11 7 11 3 5 Definition of a time point a ao o eee sses aaaa tasu 11 7 114 Running TIMEPEKO 0 2 28 cod ee eee a ee 11 8 114 1 TIMEFERO output 24 444 004 06 664 b eee ee ee 11 8 115 A TIMEFEKO example o e 11 8 12 The program LFFEKO 12 1 A o AAA ae ee RE ee a he eee 12 1 12 2 The pre input lle ooo be eee a ee ee eS 12 1 123 The geo input fle 66 ee eRe we 12 1 1231 CUTEDGE COMO o oa aa bh he eae ae 12 2 12 3 2 DELLOOP command 0 442654 444 058028 be ed 12 2 1233 INSLUOP command o o coa 244 2 66h b awe eee eS 12 2 12 34 END command cc eee RRR KO EER RRS EE 12 3 Wee o A oa 12 3 December 2002 FEKO User s Manual viii CONTENTS 13 The program ADAPTFEKO 13 1 Wad Desdipton es sh OR aS eR oO AD ai 13 1 132 Runas ADAPTFERO oo 200855 500 fhe gee a 13 1 13 3 The pre input file es 13 1 13 4 ADAPTFEKO example 000 ee ee ee 13 2 14 Description of the output file of FEKO 14 1 14 1 Geometria co cede a AAA 14 1 EZ BROMO 66 hl RA AA 14 6 14 4 Currents and Charges 2 2 ee ee a a aaa 14 7 144 Finite conductivity ccoo 14 11 145 Near Dade anr iay a a a AA aA a e de e Roa wa a 14 12 160 Far felda lt e rue crdi a ia hai i as i ek ie
54. a transmission line with a complex characteristic impedance Zz as shown in figure 9 29 The reflection factor Zaw ZL ad Zaw ZL is taken into account when calculating the incident power at the feed point December 2002 FEKO User s Manual 9 88 DESCRIPTION OF THE CONTROL CARDS The total incident power is given by ry Pay l ov and the reflected power by and the currents with the factor y s As before the total reflected power Pos s hy s D Pu rti reduces the gain of the antenna EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 89 9 2 38 SK Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 I 12 3 Ry Ra R3 R4 R5 Re R7 f A 1 1 rA 4 A Ri RS RS R4 RE RG RL Rg INT INT INT INT INT stristristristrisrr REAL REAL REAL REAL REAL REAL REAL REAL Using this card the skin effect and ohmic losses can be examined on wire segments and surface elements In addition it is possible to switch from metallic triangles to thin dielectric layers possibly consisting of multiple layers Parameters I This card affects all segments and surface elements with label I gt 0 Ideal conductivity is assumed also the default when there is no SK card for a given label All other parameters are ignored 1 Use the high frequency skin effect approximation 2 Use the static approximation of the skin effect ohmic losses 3 Use the exact expression of the skin ef
55. activated This means that any changes made to the options available on the panel will be applied immediately This is sometimes useful but with the panel activated rendering can become slow Select the block to display using the Near Fields and Far Fields drop down lists The corresponding request field type will be displayed in the black information box below the drop down list Select the colour box to change the colour of the requested near and far field display Select Points Spheres Lines or Surfaces as options to display the selected fields Points usually works well but are sometimes difficult to see when only a few request field points are present Spheres would show a few points more clearly but for a large number of field points Spheres render very slowly Lines and Surfaces are only available as options for far fields and near fields in a Cartesian coordinate system Deactivate requested far and near field display with the Request field checkbox on the Main Display Options panel EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 29 3 5 6 8 Setup Excitation This item allows the user to selectively display sources The Set number groups sources that are active at the same time i e it is incremented for each source which has the New source flag set The Source number is the number of the source in the current set Note that the AP card results in a large number of dipoles A5
56. and 3 For polygons the first point remains as is but the corner points are listed in the opposite direction The CN card changes the normal of the affected triangles but it does not change the settings of the ME card which medium is on which side of the triangle as determined by the normal vector For example triangles defined after the card ME 5 2 must have their normal vectors pointing from medium 5 to medium 2 Thus reversing the normal effectively change which medium lies on which physical side of the triangle December 2002 FEKO User s Manual 8 18 DESCRIPTION OF THE GEOMETRY CARDS 8 2 9 DK Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ri Ra R3 R4 R5 Re R7 INT INT INT INT STR STR STR STR NT REAL REAL REAL REAL REAL REAL REAL REAL With this card a dielectric or magnetic eighth of a sphere consisting of smaller cuboids can be created Parameters S Name of the centre of the sphere Sa 53 S4 The three directions 1 83 S1 93 and S S4 form the border of the eighth of the sphere All of them have to have the same length sphere s radius and be perpendicular to each other Ri Maximum side length of cuboids along the curved edge in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used Only applicable to a dielectric sphere Ra Relative dielectric constant e of the dielectric sphere Rs Conductivity o in of the sphere Ra T
57. and debugging and thus is only available in the superuser mode Normal procedure with verification of the geometry Verification of the geometry is switched off see comment below Normal version of FEKO Activates a special version of FEKO for extremely low fre quencies LFFEKO described in section 12 Activates a special version of FEKO that uses the FMM fast multipole method Activates a special version of FEKO that uses the FSSMM faster single stage multipole method Activates a special version of FEKO that uses the MLFMM multilevel fast multipole method FEKO User s Manual 8 24 DESCRIPTION OF THE GEOMETRY CARDS USE EDG 0 Normal run 1 A edg file is used to store the connectivity information of the triangles Binary format is used to keep the file size small The edg file is read if it is present and created such that it may be read at a later run if not This is used to reduce the geometry set up computation time especially for big models on large parallel computers 2 Same as USE_EDG 1 but use an ASCII formatted version of the edg file This can be copied between platforms e g when preparing models on a PC and running FEKO on a workstation but the file can become quite large EPSENT Limit separation for which two points in space are considered identical For an exact description see below If this parameter is not specified it is set internally to 107 m In most cas
58. and the values are space delimited For planar apertures it must have four parameters The absolute value and phase in degrees of the field component in the s direction followed by the absolute value and phase in the s direction see the example below The data must be such that the position increments along the s direction first For cylindrical apertures it must have five parameters The angle y in degrees followed by the absolute value and phase of the component and the absolute value and phase of the 2 component For spherical apertures it must have six parameters The angles Y and y followed by the absolute value and phase of the and components For TYPE 7 8 9 19 or 29 the data is read from the pre input file itself In this case the data must be in the normal column based input format and FOR loops etc may be used The four field components are the same as for the text data and must be entered in the real fields R3 to Rg i e columns 51 to 90 The angle y occurs in Ra and Y in R when they are required If both electric and magnetic fields are required all N2 N3 electric fields are given first followed by the same number of magnetic fields Example of AP card usage As an example consider an open ended X band waveguide radiating through a hole in a large ground plane as shown in figure 9 14 Away from the aperture the plane z 0 is perfectly conducting i e the tan
59. ar e A Be S 14 13 liT Ssparamet ri 6c ce ge GS a EE ee gaa a Ba ed a 14 15 14 8 Computation time ee GANN 14 16 Index I 1 EM Software amp Systems S A Pty Ltd December 2002 INTRODUCTION ti 1 Introduction The name FEKO is an abbreviation derived from the German phrase FEldberechnung bei K rpern mit beliebiger Oberfl che Field computations involving bodies of arbitrary shape As the name suggests FEKO can be used for various types of electromagnetic field analyses involving objects of arbitrary shapes The program FEKO is based on the Method of Moments MoM Electromagnetic fields are obtained by first calculating the electric surface currents on conducting surfaces and equivalent electric and magnetic surface currents on the surface of a dielectric solid The currents are calculated using a linear combination of basis functions where the coefficients are obtained by solving a system of linear equations Once the current distribution is known further parameters can be obtained e g the near field the far field radar cross sections directivity or the input impedance of antennas Electrically large problems are usually solved with either the Physical Optics PO ap proximation and its extensions or the Uniform Theory of Diffraction UTD In FEKO these formulations are hybridised with the MoM at the level of the interaction matrixt This is a major step in addressing the problem of solving electromagnetic problems where the ob
60. basis functions are printed to the out output file 0 All currents are printed No currents are printed resulting in a shorter output file Currents on the MoM region Currents on node between segments o e N Currents on a connection point 16 Equivalent currents on the dielectric edges 32 Polarisation currents in the dielectric cuboids 64 Currents on the PO region Combinations are possible e g with 12 8 4 currents on both segments and connection points will be written to the output file This output is not useful to general FEKO users and it tends to make the out files very large This option is therefore only supported in the superuser mode see SU card December 2002 FEKO User s Manual 9 84 DESCRIPTION OF THE CONTROL CARDS NONEFF 0 Normal matrix element calculation 1 The calculation of the matrix elements as well as the field calculation are done in an inefficient way This switch is only used to verify the result of the effective calculation It is thus only used during program development This variable program control can lead to a large reduction in the computation time When doing long calculations it is advisable to write the currents into a file by setting PS3 1 or 3 If further calculations are then to be done the currents can be read directly into memory and be processed by using the parameter PS3 2 or 3 thus the matrix elements do not have to be recalculated and the matrix equa
61. below generate the polygon in this case a triangle shown from an oblique angle in figure 8 50 is created height 6 width 8 DP A 0 0 height 2 DP B width 2 0 height 2 DP C width 2 0 height 2 PY A EG EN lu w Figure 8 50 Example for the PY card December 2002 FEKO User s Manual 8 86 DESCRIPTION OF THE GEOMETRY CARDS 8 2 31 QU Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ry Ra R3 Ra R5 Re UE ae oe ey ae REAL REAL REAL REAL REAL REAL REAL REAL Using this card a dielectric or magnetic cuboid consisting of small cuboids may be generated Figure 8 51 shows a sketch S S S Figure 8 51 Sketch illustrating the use of the QU card There are two possibilities e S S2 entered S3 and S4 empty A dielectric magnetic cuboid whose sides are parallel to the coordinate plane is generated Only S and S2 which are the coordinates of the opposite corners are needed This version is shown in figure 8 51 on the left e Si S2 S3 and Sy entered The cuboid may have an arbitrary orientation in space S1 is the reference point From this point the other three points S2 S3 and S4 are defined They are three neighbouring corners of the cuboid Care has to be taken to ensure that the cuboid is rectangular i e the lines S S2 S S3 and S S4 must be perpendicular to each other This version is shown in figure 8 51 on the right Paramet
62. clear release the FEK or NEU file model data 3 5 5 15 Solution information Not available in WinFEKO yet See beginning and end of the output file for solution info associated with memory usage and solution times 3 5 6 Display menu Used to set various options for the display of the geometric model 3 5 6 1 Geometry Main display options The Main display options panel is the default active panel when WinFEKO is loaded Here the most often used model display options can be selected With this panel active all WinFEKO hot keys can be used see section 3 3 Under Visibility the following options are available e Axis arrows Toggle axis display e Aris small Toggle display of small axis in upper right corner of render screen e Axis grid Toggle axis grid values display e Cutplane Activate cutplane options see also section 3 5 6 5 e Elt direction When selected the back of surface elements will be displayed in a different colour shade than the front Front and back are defined according to the right hand rule December 2002 FEKO User s Manual THE PROGRAM WINFEKO Elt number When selected the number associated with each segment element polygon or cuboid will be displayed This will slow down the model display and rendering considerably with large models Fast rotation Select this to render a boundary box around the model on dynamical rotation panning and zooming as well as on zoom to window This is very usef
63. completion hit the Animation button to display the recorded bitmap pictures Hit the Stop button to stop the animation display For Bmp animation the animation speed and Continuous animation selection can be changed after the animation preparation has been completed If the animation steps are changed the Prepare animation button must be clicked again to prepare the new set of animation pictures For Bmp animation one can also manually flip through the recorded bitmap pictures by changing the wt in the spin box after the animation preparation For Gif animation the animated gif can be saved to file by hitting the Save animated gif button Click Close to close Animation control This will also release the memory allocated by the bitmap pictures 3 5 5 12 Currents On selection of this item the surface and line current data is loaded from the current project output file if available the OS card must have been used and the Current display options panel is activated A colour coded display of the surface and line currents is displayed on the model geometry Right click on the current display to view information associated with the currents at the point of selection on the rendering scene Note See the comments on the Apply OK and Cancel buttons in section 3 5 5 7 Select a frequency and current block from the lists under Data block selection Select the Arrows Colour or Smooth options under Current display The Smooth option results i
64. control panel see section 3 5 7 2 Go to Find element panel see section 3 5 7 1 Toggle label display This button sets the Colours option in the FEK file display options panel to Label number and activates the Legend under Visibility on the Main display options panel This provides a quick way to display label numbers If the Colours option in the FEK file display options panel is already selected when this button is clicked label display is switched off DO 3 0 00h W N Goto Entity selection panel see section 3 5 7 4 EM Software 4 Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 5 3 4 4 RESULTS control toolbar Used to load and display data obtained from the output file Dal 2 3 4 5 6 7 8 9 10 11 12 13 View output file see section 3 5 5 1 View currents see section 3 5 5 12 View 3D polar patterns see section 3 5 5 7 View near field ortho slices see section 3 5 5 10 View near field iso surfaces see section 3 5 5 9 Start GraphFEKO see section 5 Antenna Parameters see section 3 5 5 2 S Parameters see section 3 5 5 3 oO AN DOT A WwW YF Network Parameters see section 3 5 5 4 E o Receiving Antenna Parameters see section 3 5 5 5 2D Far field plots see section 3 5 5 6 2D Near field plots see section 3 5 5 8 Open GraphFEKO to extract continuous frequency results e e won e 3 4 5 RENDER control toolbar Used to cont
65. creates a pre file for FEKO to ensure its validity OPTFEKO internally still assumes that for example the obtained input impedance is for the original set of parameters i e one should still add a penalty function in order to force the optimisation algorithms to move back into the valid param eter range 10 3 2 Definition of the penalty function To ensure that the optimisation parameter x stays within the bounds Cmin and Lmazx a penalty function can be added to the aim function The penalty function P is defined by EM Software amp Systems S A Pty Ltd December 2002 THE OPTIMISER OPTFEKO 10 3 the equation 10 Pp a mM for lt Lin P 0 for Tmin lt T lt Umax 10 P Imaz for 2 gt Dias Tmas Tmin The two parameters P and P define the value of the penalty function when overestimat ing the allowable value by 10 When the penalty function is added to the aim function it must be ensured that they both are of the same dimension The penalty function is defined with the keyword PENALTYFUNKTION or PENALTY_FUNCTION In the rows that follow the optimisation parameters P and P are specified P and P in the first row are associated with the first parameter in the optimisation parameters section P and P in the following rows are associated with the optimisation parameters defined in the corresponding rows If no penalty function should be assigned to a specific optimisation parameter P P 0 should be set I
66. during the iterations a fast backward substitution is applied 128 Incomplete LU decomposition ILU 0 preconditioning BCGFLAG Parameters for the BCG when CGMSEL 3 1 Fletcher s method 2 Jacobs method 3 Fletcher s method pre iteration using Fletcher s method 4 Feltcher s method pre iteration using Jacobs method 5 Jabobs method pre iteration using Fletcher s method BLOCKNB The block size to be used for LU decomposition with LAPACK CGMSEL 5 as well as for the Block Jacobi preconditioning When nothing is specified appropriate standard values are used for LAPACK and the block preconditioners PREC Termination criterion for the normalised residue when using iterative methods Normally the CG card should not be used in which case an optimum solution based on a LU decomposition is selected normally CGMSEL 5 for the sequential version of FEKO and CGMSEL 19 for the parallel version for the solution using main memory when storing the data on disk a similar process is employed automatically The CG card is only relevant in special circumstances for example to select an iterative solution process EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 45 If more than one direction of incidence of a plane wave has been defined in the AO card the Gauss Elimination with CGMSEL 0 or 5 should be used because an LU decomposition of the matrix is stored In such a case onl
67. end Q2 points of the arc The third control point Q1 lies at the cross point of the two lines that lie tangential to the arc at QO and Q2 respectively Define the y value of this point y_Q1 tr sqrt 2 1 With M lying on the middle of the line between QO and Q2 and S on the xx intersection between the circular arc and the line between M and Q1 the weight of point Q1 is the ratio of the lengths M S to S Q1 w_Q1 sqrt 2 sqrt 2 2 DP QO r 0 0 0 0 1 DP Q1 r y_Q1 0 0 w_Q1 DP Q2 r sqrt 2 r sqrt 2 0 0 1 Create the Bezier surface IP edg_len NU 1 2 QO Qi Q2 PO PI P2 Copy and rotate the 45 degree structure to a quarter disk TG 1 0 0 0 180 0 90 0 EG EN Figure 8 37 Demonstation of using the NU card to generate flat surfaces December 2002 FEKO User s Manual 8 70 DESCRIPTION OF THE GEOMETRY CARDS Third example of NU card usage The linear quadratic shape in figure 8 38 is generated with Linear quadratic demo for the NU card IP 0 1 DP AA 0 1 0 0 DP AB 0 i 0 3 DP AC 0 1 2 0 1 0 8 DP BA 1 0 2 0 3 0 6 DP BB 1 2 0 9 0 2 DP BC 1 1 1 8 0 1 1 2 NU 1 2 AA AB AC BA BB BC EG EN AB BC BB Figure 8 38 Linear quadratic example using the NU card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 71 8 2 26 PB Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ri Ra mo a R INT NT REAL REAL REA
68. field then shows the segments available in that current block Port 2 is assumed to be on the selected segment The Labels list is included for future use and is not active at present Click to highlight a frequency and select a source and port 2 segment for this frequency The data for the parameter selected under Quantities is displayed Plotting the network parameters as a function of frequency The network pa rameter quantities can be plotted as a function of frequency if more than one frequency solution is available The Parameter data option panel will change to the Plot options panel when a range of frequency values in the frequency block are selected Click and drag with the mouse to select multiple frequencies Under Scale the user can select a linear or logarithmic scale to use a logarithmic scale the plot parameter must remain larger than 0 or he can plot the quantity in dB If any of the quantities selected have negative values and either Log or dB scaling has been selected then a warning will be given and the graph will be plotted on a linear scale The Subtract Z_load field gives the system impedance which is used for Si and S21 calculations If S21 calculations are required both the source and port 2 segment should be loaded with the system impedance with for example LZ cards If this is the case the Subtract Z_load should be checked If the ports are not loaded it should be left unchecked but then S21 plots are not
69. file 3 5 5 1 View output file Select this item to load the output file A FEKO output file read only editor is opened and the Output file display options panel is activated Type in a string in the Search for text edit box Hit the Search button to search for the text The other buttons are mostly speed buttons for quick searching of a specific text string in the output file for example when the WARNING button is clicked the Search for text edit box is filled with the text string WARNING after which the Search button is automatically clicked 3 5 5 2 Antenna parameters When this item is selected the program GraphFEKO is executed with the current project out file passed as the first command line parameter GraphFEKO starts and automat ically selects the current project out file and loads the antenna parameter data if it exists The Antenna parameters panel in GraphFEKO is also activated automatically Select this item to load and display Vin Lin Zin Yin S11 and other antenna parameter data For further information see section 5 Note that every time this item is selected from within WinFEKO the program Graph FEKO will be executed If GraphFEKO is already running with the current project out file selected rather use the Import Antenna parameters menu item in GraphFEKO to load the antenna parameter data December 2002 FEKO User s Manual 3 14 THE PROGRAM WINFEKO 3 5 5 3 S parameters When this item
70. from FEMAP The points defined in the NASTRAN file will then available in PREFEKO as points as if they were defined by DP cards of the form Nxxx where xxx is the index of the grid point This may be used for example to attach additional structures to the geometry In addition the coordinate values of the point are available as variables in PREFEKO For example the variables n1234x n1234y and n1234z give the coordinates of the NASTRAN grid point with index 1234 Note that points are not included by default Since grid points do not have an associated property points are imported irrespective of their label Each line in the column based format consists of one keyword such as GRID starting in column 1 From column 9 onwards follow 9 input fields with a width of 8 characters each Thus input field 1 uses columns 9 to 16 input field 2 columns 17 to 24 etc The ninth and last input field 9 ends at column 80 Below is December 2002 FEKO User s Manual 8 38 DESCRIPTION OF THE GEOMETRY CARDS a very simple NASTRAN example file consisting of a plate property 1 subdi vided into eight triangles and a rod property 2 subdivided into two segments j l py ID XXXXXXXX YYYYYYYY CEND BEGIN BULK GRID GRID GRID GRID GRID GRID GRID GRID GRID GRID GRID CROD CROD CTRIA3 CTRIA3 CTRIA3 CTRIA3 CTRIA3 CTRIA3 CTRIA3 CTRIA3 ENDDATA pb COON OOKRWNHK e ONODoOBRWNRP OOF ig ee a pp eB amp N e
71. gt to Uo ugo ui Toh w 11 4 l e 7 e 72 f h 71 gt fe 72 gt be T gt Figure 11 4 Double exponential pulse Example Pulse form DEXP xk tO T taul tau2 0 0 10 0E 09 5 0E 9 10 0E 9 EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM TIMEFEKO 4 Ramp pulse 0 t ta t TEE 1 u t ugo t tz t TEET 2 0 T T 71 sat Ty 2 2 ui t Uo RAMPE RAMP see figure 11 5 11 5 for t lt ti to for ty to lt t lt ta to for ta El to lt t lt t3 Eg to 11 5 for t3 to lt t lt t4 to for t gt ta T THT t 2 t z 11 6 f f 1 KY i Po TT ti i ta 71 gt i ha T Figure 11 5 Ramp pulse Example Pulse form RAMP tO Impuls Duration T 20 0E 09 15 0E 09 5 Double exponential impulse second type 0 t to wite ugo gt T Example Impulse form DBLEXP Time tO Parameter taui 20 0E 9 70 0E 9 December 2002 e T2 ta ta t a4 gt taul tau2 5 0E 09 10 0E 09 DBLEXP DBLEXP see figure 11 6 for t lt to t t 2 for t gt to ae Parameter tau2 5 0E 9 FEKO User s Manual 11 6 THE PROGRAM TIMEFEKO 0 8 0 7 0 6 0 5 u t 0 4 0 3 0 2 0 1 2 0 2 4 6 8 10 t 8 Figure 11 6 Double exponential impulse second type 11 3 2 Definition of the frequency block The upper frequency limit fmax and the number of frequency points N a
72. input impedance Z which includes the loading impedance One must therefor subtract the loading impedance from the cal culated value to get the actual input impedance If the source segment has been loaded with the system impedance in the pre file the Subt Z_load option should be checked if no loading has been applied this box should be unchecked Plotting the input impedance on a Smith Chart If Smith chart is selected under the Scale options the input impedance is plotted on a Smith chart This represents the magnitude and phase of S11 but the grid is labeled according to the normalised impedance The chart is normalised to the impedance specified by the Zo ohm field discussed above EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM GRAPHFEKO 5 7 The grid labels can be switched off by editing the Right axis on the Azis tab of the Chart tab of the advanced editor see section 5 3 3 2 The grid density can be controlled by setting the Desired increment field on the Scales tab of the same axis Both the real and imaginary circles uses this increment between 0 and 1 and the inverse of these values between 1 and infinity The points on the Smith chart can be numbered to allow an indication of which frequency is associated with each point Select the Series tab of the advanced editor then select the appropriate series and check Visible box on the Marks tab Plotting the antenna parameters The Quantity s field allows
73. is selected GraphFEKO starts selects the current project out file and loads the S parameter data as calculated on request of an SP card see section 9 2 39 The S parameters panel in GraphFEKO is also activated automatically If GraphFEKO is already running with the correct out file selected rather use the Import S parameters menu item in GraphFEKO to load the S parameters 3 5 5 4 Network parameters When this item is selected GraphFEKO starts automatically selects the current project out file and loads the network parameter data if it exists The Network parameters panel in GraphFEKO is also activated automatically Select this item to load and display S11 S21 and the calculated currents in selected segments For further information see section 5 If GraphFEKO is already running with the correct out file selected rather use the Import Network parameters menu item in GraphFEKO to load the network parameter data 3 5 5 5 Receiving antenna Rx When this item is selected GraphFEKO starts automatically selects the current project out file and loads the receiving antenna data if it exists The Antenna reception panel in GraphFEKO is also activated automatically Select this item to load and display the calculated currents in selected segments as a function of incident wave direction or frequency This data can only be extracted when an incident wave has been used as excitation For further information see section
74. length in m radius in m 1 O 0 0000E 00 0 0000E 00 2 7700E 00 1 O 0 0000E 00 0 0000E 00 2 1625E 00 6 0750E 01 2 7700E 02 2 O 0 0000E 00 0 0000E 00 2 1625E 00 i 2 O 0 0000E 00 0 0000E 00 1 5550E 00 6 0750E O1 2 7700E 02 3 O 0 0000E 00 0 0000E 00 1 5550E 00 2 3 O 0 0000E 00 0 0000E 00 9 4750E 01 6 0750E 01 2 7700E 02 Here each segment is assigned a consecutive number In the second column the label of the segment appears and below it the number of the medium in which it finds itself A zero 0 means free space vacuum Then the coordinates of the begin and end points of the segment follow In the previous row the numbers of the nodes that are adjacent appear A positive sign for the node number indicates that the positive current direction is defined away from the segment When there is a negative number then the positive direction is towards the segment In the next row the length of the segment appears followed by the radius December 2002 FEKO User s Manual 14 4 DESCRIPTION OF THE OUTPUT FILE OF FEKO For the data of the nodes between the segments a data table is given DATA OF THE NODES BETWEEN THE SEGMENTS no of segment points of segm No ISEGP ISEGM KNOP KNOM 1 1 2 2 1 2 3 2 1 3 3 4 2 1 info of symmetry yz XZ xy status 0 0 5 unknown 0 0 6 unknown 0 0 7 unknown The consecutive numbers of nodes are given in the first column Then the number ISEGP and ISEGM of the two connected segments follow A positive curren
75. must lie completely within one layer or at the boundary between layers If for example a metallic wire penetrates a multilayer substrate the segmentation must be such that there is a node on each interface between layers See example_31 in the Examples Guide EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 73 The following is not possible with this Green s function dielectric ground hybrid MoM PO method hybrid MoM UTD method dielectric bodies with surface equivalence principle December 2002 FEKO User s Manual 9 74 DESCRIPTION OF THE CONTROL CARDS 9 2 28 L4 Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 La la 13 Ri Ra R3 Ra R5 Re A IE REAL REAL REAL REAL REAL REAL REAL REAL This card can be used to add a load between a metallic triangle and the ground plane for the planar multilayer Green s function without having the requirement to model a vertical current element analogous to the A4 excitation card Parameters I gt The label of the triangle to load If there are more than one triangle with this label the one with the highest element number is loaded Alternatively the user may set 2 1 and specify the Cartesian coordinates x R3 y R4 and z Rs of the load point The triangle with the centre point closest to this point is loaded Iz 0 The specified impedance refers directly to the load point cen troid of the triangle 1 The specif
76. no dielectric bodies or dielectric ground e only perfectly conducting flat polygonal plates or a single cylinder allowed in the UTD region e no UTD and PO at the same time EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 101 8 2 39 UZ Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Ry Ra R3 R4 R5 TA ae ey NT NT REAL REAL REAL REAL REAL REAL REAL REAL With this card a cylinder is created for the UTD region figure 8 56 shows a sketch S Figure 8 56 Sketch for UZ card with a cone shaped end cap height h from point S and flat surface end cap at point S2 Parameters S Name of the starting point of the cylinder axis S2 Name of the end point of the cylinder axis S3 Name of a point on the rim at the side of S1 For a cylinder segment this is the corner point Ri The angle in degrees of the cylinder segment R Flag for the type of end cap on the S side It has the following meaning 1 No end cap thus the cylinder is semi infinite on this side 0 Flat end cap in the form of a disk sector 1 Spherical end cap 2 Elliptical end cap with height h Rs 3 Cone shaped end cap with height ha Rs December 2002 FEKO User s Manual 8 102 DESCRIPTION OF THE GEOMETRY CARDS R3 Height of the end cap on the S side only applicable when Ra 2 or Ra 3 in m is scaled by the SF card Ra Flag for the type of end cap on the S side It has t
77. node point dielectric cylindrical shell end of the geometric input generation of a segment of an ellipsoid defines a Fock area creates a coil from wire segments reads an external Include file containing the geometric information sets the parameter that defines the degree of meshing defines the border of the PO area creates a circular conical segment sets the wedges in the PO area creates a circular element creates a spherical element specifies the label for segments triangles polygons etc defines the medium specify a NURBS surface from specified control points generation of a paraboloid create a flat plate with an elliptic hole create a polygonal shape that is meshed into triangles applies the Physical Optics approximation 5In general all the geometry cards must appear before the EG card Exceptions are the IN card when including pre files with control commands and the DP and TP cards which may be used to define points for the AP card December 2002 FEKO User s Manual 8 2 PY QU SF SU SY TG TO TP UT UZ WG ZY DESCRIPTION OF THE GEOMETRY CARDS creates a polygonal surface for use with UTD or PO creates a dielectric or magnetic cuboid enters a scaling factor with which all dimensions are multiplied switches the program into the superuser mode utilise symmetry in the construction of the geometry transformation i e translation and rotation of the geometric structures creates a toroid transform a
78. number is reduced by approximately a factor of 101 Figure 12 1 Surface Current Distribution on the surface of the sphere EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM ADAPTFEKO 13 1 13 The program ADAPTFEKO 13 1 Description In examples with narrow resonances a fine frequency resolution is required to locate these resonances If the frequency band is large a very large number of analysis may be required if simple linear or multiplicative frequency stepping is used ADAPTFEKO is used to overcome these problems It uses an adaptive frequency sampling and interpolation automatically using smaller steps near resonances and larger steps where the results are relatively smooth For each frequency it creates a pre file and calls PREFEKO and FEKO The file names are derived from the original name plus _ada_ plus a numerical value for exam ple the new files associated with forked_dipole pre are forked_dipole_ada_1 pre forked_dipole_ada_2 pre 13 2 Running ADAPTFEKO ADAPTFEKO is started automatically by RUNFEKO if the FR card contains the flag for adaptive frequency sampling see sections 7 2 and 9 2 26 The syntax is runfeko filename runfeko filename adaptfeko options options where the optional argument options in the second line may be keep files All solution files pre fek out etc are preserved restart x Restart an adaptive frequency analysis using results for the frequency po
79. number real part imag part magn phase 1 2 6923E 03 9 6710E 04 2 8607E 03 160 24 2 2 6923E 03 9 6710E 04 2 8607E 03 160 24 3 2 6923E 03 9 6710E 04 2 8607E 03 160 24 For a dielectric solid surface current method the equivalent surface current EQUIVALTENT ELECTRIC CURRENTS ON TRIANGLES in A m no of edge real part imag part magn phase 1 1 3380E 03 7 8979E 04 1 5537E 03 30 55 2 0 0000E 00 0 0000E 00 0 0000E 00 00 3 1 9138E 03 1 3635E 04 1 9187E 03 175 92 4 1 5428E 03 1 2464E 03 1 9834E 03 38 93 5 2 8018E 04 3 9938E 04 4 8786E 04 125 05 and the equivalent magnetic current EQUIVALENT MAGNETIC CURRENTS ON TRIANGLES in V m no edge real part imag part magn phase 1 1 0505E 00 4 9770E 01 1 1625E 00 25 35 2 0 0000E 00 0 0000E 00 0 0000E 00 00 3 2 5042E 02 5 8154E 01 5 8208E 01 87 53 4 9 1269E 01 1 2119E 01 9 2071E 01 7 56 5 9 2055E 01 5 5293E 01 1 0738E 00 149 01 is given for each basis function on an edge In the case of dielectric cuboids the polari sation current is given for each cuboid EQUIVALENT ELECTRIC CURRENTS AT VOLUME ELEMENTS in A m m Cuboid 11 12 I3 number magn phase magn phase magn phase 1 6 1821E 11 113 21 4 0629E 11 127 75 4 4212E 00 52 33 2 4 2163E 11 106 10 1 9748E 11 127 90 3 7752E 00 52 58 3 5 9327E 11 99 04 1 6515E 11 128 34 2 4592E 00 53 12 EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE OUTPUT FILE OF FEKO 14 9 The OS card can request t
80. of a patch antenna with a vertical pin December 2002 FEKO User s Manual 9 16 DESCRIPTION OF THE CONTROL CARDS 9 2 8 A5 Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 NF EIR1 EIR2 EIR3 EIR4 EIR5 EIR6 EIR7 A IE REAL REAL REAL REAL REAL REAL REAL REAL This card specifies excitation by an electric Hertzian dipole Parameters ANFL 0 New excitation replaces all previous excitations 1 Additional excitation add to previous excitations EIR1 Absolute value of the complex amplitude J lin Am EIR2 Phase of the complex amplitude I l in degrees EIR3 x coordinate of the position of the dipole in m EIR4 y coordinate of the position of the dipole in m EIR5 z coordinate of the position of the dipole in m The values EIR3 EIR4 and EIR5 are scaled by the SF card if SKALFLAG 1 EIR6 Orientation of the dipole in space Angle Y in degrees from the z axis analogue to the incidence direction in figure 9 3 EIR7 Orientation of the dipole in space Angle y in degrees is the projection of the dipole onto the plane z 0 opposite the x axis analogue to the angle of incidence in figure 9 3 The dipole moment of the electric dipole is given by Il pS Jw The power radiated by the dipole in a free space environment is given by _ 6B Zo MP apra 127 127Z Fo P FEKO however considers the properties of the medium in which the dipole is located as well as the coupling of the dipole with surrounding structures or other so
81. of the control cards December 2002 FEKO User s Manual 2 2 GENERAL COMMENTS 2 2 Summary of the files The table below gives an overview of the different files and their respective functions STDOUT is the standard output usually the screen A is used to symbolically indicate the filename Filename Description STDOUT Usually the screen This is where comments such as progress warnings and errors are sent _14 Page temporary storage file for the matrix in the sequential version of FEKO with out of core solution _15 Page temporary storage file for the matrix in the sequential version of FEKO with out of core solution _16 Page temporary storage file for the matrix in the sequential version of FEKO with out of core solution _20 Page temporary storage file for the coupling coefficients of the MoM PO hybrid method during an out of core solution _21 Page temporary storage file for the coupling coefficients of the MoM PO hybrid method during an out of core solution afo Continuous frequency results created by ADAPTFEKO aus Output file of TIMEFEKO bof Binary version of the output file which is used for post processing cgm Contains the size of the residue that results from the iterative algorithm which solves the matrix equation and the number of iterations This file is only generated on request by a DA card section 9 2 21 dbg When using the UTD it is possible to request an optional
82. of the coordinate system to the centre of the sphere such that the near field calculation can be executed in spherical coordinates EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 81 9 2 35 OS Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 DO LAB OS LAB OS OS AVER OS2 AGE A IE REAL REAL REAL REAL REAL REAL REAL REAL With this card the currents on the surfaces and the segments can be extracted Parameters DOOS 0 No current output but does start calculation Output all currents segments and triangles Output all currents on triangles metallic and dielectric Only output the currents on metallic segments ah NAO Output all currents on segments and triangles with the label LABOS See also DOOS 7 which allows a range of labels 5 Export the currents on all segments to a rsd file in Ca bleMod format see the comment below 6 Export the currents on all segments with labels in the range LABOS LABOS2 to a rsd CableMod file 7 Output the currents on all segments and triangles with labels in the range LABOS LABOS2 LABOS Label for the selection when DOOS 4 If DOOS is set to 6 or 7 this is the start label OSAVERAGE 0 For the output of currents in the vertices of the triangles neighbouring triangles with common vertices are identified The current densities are then averaged over the neighbours This ensures that the graphical representation is
83. of the polarisation left right linear If the FF card is used with NTHETA gt 2 and NPHI gt 2 the Pointing vector is integrated over the specified sector see the detailed discussion given with the FF card in section 9 2 25 The result is the radiated power and is given below the field values December 2002 FEKO User s Manual 14 14 DESCRIPTION OF THE OUTPUT FILE OF FEKO When analysing an antenna the source power calculated from the input impedance should equal the integral of the radiated power over the surface of a sphere This may be used as a partial validation of the result Note that power losses in dielectrics and finite conductivity should be taken into account separately The use may also elect to integrate the far field power without writing the field values to the output file using the FF card with FFREQ 3 FEKO then produces the output VALUES OF THE SCATTERED ELECTRIC FIELD STRENGTH IN THE FAR FIELD in V Factor e j BETA R R not considered Integration of the normal component of the Poynting vector in the angular 2701 sample points radiated power 1 05642E 03 Watt 1 04095E 03 Watt grid DTHETA 5 00 deg and DPHI 5 00 deg angular range THETA angular range PHI 2 50 182 50 deg 2 50 362 50 deg 0 00 180 00 deg 0 00 360 00 deg Polarisation dependent radiated power horizontal polarisation 3 63158E 04 Watt vertical polarisation 6 77792E 04 Watt S polarisation 5 19105E 04 Watt Z pol
84. of the starting point of the arc S4 If this field is empty then an arc consisting of segments is generated If there is an entry in this field then an arc that forms the border to the PO region is generated S4 is then the label of the bordering triangles Ri The subtended angle y in degrees The direction is in the positive sense around the S S3 axis R Maximum length of the segments that make up the arc in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used R3 Normally the wire radius is set with the IP card Setting R3 overrides this radius for the current arc without affecting the default for later segments Ra is in m and is affected by the SF card scaling factor Ra By setting the parameter R4 it is possible to create a wire with a tapered radius The parameter R3 must also be set R3 then specifies the radius at point S3 while R4 specifies the radius at the other end EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 15 Rs If this parameter is empty or is set to 1 a circular wire are is created The parameter R5 may be used to generate an elliptical arc within reasonable limits Rs 2 gives the ratio of the two half axes of the ellipse where a is the distance 51 53 Quite often modelling the geometry of an arc requires shorter segments than those used for straight wires Thus the maximum segment length specified with th
85. or r direction dependent on FELKOR DY Increment size in y or y or Y direction DZ Increment size in z or direction R8 If RS is set to 1 the old format of the near field is used in the out output file This should only be used for compatibility with third party post processors Note that WinFEKO and Graph FEKO cannot extract SAR values from near fields in this format Note that all coordinates are metre and all angles in degrees Scaling with the SF card is only applicable when the option SKALFLAG 1 is selected highly recommended in this case coordinates must be in metre after scaling Potentials cannot be computed with the FE card if UTD or PO is used Also only the free space Green s function is supported but not the Green s functions for layered spheres or multilayered planar media If the total potentials are requested the potentials for the sources are added These are not available for a plane wave AO card or an impressed radiation pattern AR card and FEKO will give an error For a magnetic dipole A6 card if the electric ring current model is used one will get A and if the magnetic current model is used one may compute F and V w all the other potentials are zero If one requests efe and or hfe files with the DA card then A and V y are written to the efe file while F and V wy are written to the hfe file The different possibilities of FELKOR are described on the following pages December 2002 FEK
86. output file containing a large amount of additional data and may therefore be very large see the UT card dxf AutoCAD geometry file which can be imported with the IN card Only lines and meshed polygons are imported see section 8 2 16 edg Geometric data is taken from the fek input file where for example common edges between triangles are found This reprocessed informa tion of the geometry is saved in the edg file EG card section 8 2 12 efe File containing the electric field strengths Contains both the position and the complex components of the electric field strength vectors This file is only generated on request by a DA card section 9 2 21 fek Output file from PREFEKO serves as the input file for FEKO ffe File containing the far field data This file is only generated on request by a DA card section 9 2 21 geo In addition to the pre file a geo file is required with the special low frequency program LFFEKO low frequency FEKO 12 g e Interpolation table of the electric field strengths for the Green s function of a layered sphere gfh Interpolation table of the magnetic field strengths for the Green s func tion of a layered sphere EM Software amp Systems S A Pty Ltd December 2002 GENERAL COMMENTS XA XX k k hfe sigd log mat mod nas neu Opt ofc 0S out pre ray rhs rsd snp Str tim vis w
87. parameters must be assigned absolute values and not normalised values The amplitude factor uy is 1 It can be changed by using the Ax card in the file pre with the appropriate amplitude value Time shifting to indicates the time in seconds that the pulses are delayed see the shift in figure 11 1 The time shift should be such that the excitation of the structure 0 at t 0 is approximately 0 Since the both the time and frequency domain data are continuous this is not strictly required but it simplifies working with the results EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM TIMEFEKO 11 3 ul 0 uo gt p T t T to to T t to gt Figure 11 1 Time function uy t shifted by to The following pulses are available 1 Gaussian pulse GAUSS GAUSS see figure 11 2 u t upe ta 11 1 ul t A uo t Figure 11 2 Gaussian pulse Example Pulse form GAUSS tO Exponent a 2 0E 08 3 0E 08 2 Triangular pulse DREIECK TRIANGLE see figure 11 3 lt tol 1 f t to lt T u t u E ee 11 2 0 for otherwise Example Pulse form TRIANGLE to Impuls Duration T 2 0E 08 1 0E 08 December 2002 FEKO User s Manual 11 4 THE PROGRAM TIMEFEKO uo T T Figure 11 3 Triangular pulse 3 Double exponential pulse DEXP DEXP see figure 11 4 0 for lt to _ t to ui t lt U 1 e Ta for to lt t lt T to 11 3 t to ue 72 for t gt T
88. point parameters for the uniform theory of diffraction UTD creates a cylinder for use in the UTD region creates a parallelogram consisting of a wire grid creates a cylindrical element EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 3 8 2 Alphabetical description of the geometry cards 8 2 1 Card INT INT wr INT ane REAL REAL REAL REAL REAL REAL REAL REAL The card is not a command but defines a comment line Everything that is found in this line is ignored by PREFEKO Normally the filename has to be found in the first line of the pre file If the first line happens to be comment line then the filename will automatically be placed in the first line of the file fek by PREFEKO It is possible to add a comment to the end of an existing line or card For example Definition of Parameters lambda 1 0 Wavelength radius lambda 2 Cylinder radius height 2 lambda Cylinder height December 2002 FEKO User s Manual 8 4 DESCRIPTION OF THE GEOMETRY CARDS 8 2 2 BL Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 Ri Ra mo ae uae NT NT REAL REAL REAL REAL REAL REAL REAL REAL Using this card two points are connected to form a line which is then subdivided into segments The points have to be defined by a DP card prior to using this card The wire radius is set by an IP card preceding the BL card but can be set locally Figure 8 1 shows an ex
89. points on one side must be identical use the same point The weights of the control points are specified at the DP card Note that for higher order B zier curves the surface does not pass through the control points except those on the corners First example of NU card usage The saddle point shape in figure 8 36 is generated with Demo for the NU card DP AA 0 0 0 DP AB 0 1 0 5 DP BA 1 0 2 0 6 DP BB 1 2 0 9 0 1 IP 0 1 NU 1 1 AA AB BA BB EG EN December 2002 FEKO User s Manual 8 68 DESCRIPTION OF THE GEOMETRY CARDS Z BB Figure 8 36 Saddle point example using the NU card Second example of NU card usage NURBS may also be used to generate flat surfaces with curved edges The section of a circular plate with a square hole in figure 8 37 is generated with the file Demo for the NU card Square hole in a circular plate Structure variables r 1 0 Radius of circle ta 0 4 Half width of rectangle edg_len 0 15 Maximum edge length We will use a first order interpolation in the radial direction and second order along the arc thus also along the border of the hole Data points along the hole just a straight line DP PO a 0 0 1 DP Pil a a 2 0 1 DP P2 a a 0 1 EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 69 Data points along the 45 degree arc The first two control points lies at the start Q0 and
90. possible The Quantity s field allows the following parameter quantities e S_11 the reflection coefficient S in a Zo ohm system See section 5 3 2 3 for a description of the S11 calculations S11 is calculated for the source selected under Source nr and it is assumed that only one source is active e S_21 the transmission coefficient S21 in a Zo ohm system For S21 calculation in a two antenna system with Zo feed lines the feed segment of each antenna must have been loaded with Zo see also section 5 3 2 3 then the Subtract Z load field must be checked S21 is calculated from I Sa 22 2 Vi with Vin the voltage applied to the transmit antenna and T gt is the current on the receive antenna Zo loaded segment as calculated by FEKO December 2002 FEKO User s Manual 5 10 THE PROGRAM GRAPHFEKO S21 is calculated for a transmit antenna whose feed segment is selected in the Source nr drop down listbox and a receive antenna attached to the segment selected in the Segments listbox under Target selection More than one segment in the Segments listbox can be selected for plotting on the same graph The absolute segment numbers are listed and the user must ensure that the correct or required segment number is selected by verifying the segment number with WinFEKO e 11 the current J on the source This allows plotting the current on the various sources as selected under Source nr e 12 the current I on the port 2
91. resistance inductance and capacitance LE defines a load on the edge between surface triangles LP defines a parallel circuit load consisting of resistance inductance and capaci tance LS defines a series circuit load consisting of resistance inductance and capacitance LZ defines a complex load OF offset i e displacement of the origin when calculating the near fields OS saves the surface currents in a file PS set general control parameters PW defines the radiating power of a transmitting antenna SK takes a finite conductivity into account through the skin effect of ohmic losses also for thin dielectric layers SP calculates the S parameters for the active sources TL specifies a non radiating transmission line December 2002 FEKO User s Manual 9 2 DESCRIPTION OF THE CONTROL CARDS As mentioned above the control cards form the second part of the input file see also section 2 1 Control cards are processed line by line and only affect other cards and calculations specified below them in the input file Information specified in a control card is not available before that line is processed Any number of control cards can be used but they should adhere to a basic sequence Thus for example the frequency FR card and the type of excitation Ax card must be defined before the near fields can be calculated with an FE card In addition a sensible order for the control cards can result in a considerable reduction
92. segment This allows plotting the current on the selected receive port More than one segment in the Segments listbox can be selected for plotting on the same graph For each of these quantities the user may plot the real and imaginary parts the magnitude and phase However in most cases one may only plot either the real and imaginary parts or the magnitude or the phase at a time It is possible to use the Add to graph button to plot for example the magnitude of a current on the same graph as the real part The New graph button plots the frequency dependent data for the quantities selected on a new graph The Add to graph button sends data for the selected quantities to the active graph window The Cancel button closes the Network parameters panel and activates the Main graph settings panel Plotting the currents on a number of segments It is also possible to plot the current on a number of segments by selecting a single frequency and the Jz quantity We will discuss this in more detail in section 5 3 2 7 5 3 2 6 Receiving antenna Rx This item must be selected to extract induced current data on segments with a plane wave incident field as excitation The Antenna reception panel in GraphFEKO is activated The various frequencies at which the FEKO solution has been obtained are displayed in the Frequency box The Inc field block item represents different incident angles for a plane wave incident field The Cur block field allows the
93. selected FEKO output file The Far fields panel in GraphFEKO is activated The various frequencies at which the FEKO solution has been obtained are displayed in the Frequency box The Block no field lists the FF cards in the order they appear in the output file Blocks which only integrate the fields without writing field values to the output file are not listed Under Scale the user can select a linear or logarithmic scale to use a logarithmic scale the plot parameter must remain larger than 0 or he can plot the quantity in dB If any of the quantities selected have negative values and either Log or dB scaling has been selected then a warning will be given and the graph will be plotted on a linear scale In addition the user can specify if a Polar amplitude versus angle or Line graph standard rectangular 2D plot of the quantity value as a function of the independent variable should be created As before the New graph button plots the frequency or direction dependent data for the quantities selected on a new graph the Add to graph button sends data for the selected quantities to the active graph window and the Cancel button closes the Current extraction panel and activates the Main graph settings panel Various components can be plotted for each of the three quantities e Gain Directivity GraphFEKO can plot the gain or the directivity depending on which one was re quested by the far field card If either gain or directivity is s
94. side_l side_l 0 Finally generate the metallic surfaces on the dielectric boundary metallic triangles on the surface of a dielectric body normal vector pointing from medium 0 to medium 1 0 1 1 A AO C 90 side_1 Introduction of symmetry SY 1 2 3 End of geometry section EG 1 Specify the dielectric parameters for medium 1 medium O defaults to free space no need to set the parameters separately DI 1 Additional cards excitation frequency calculation requests End EN EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 67 8 2 25 NU Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 I T2 S S2 S3 Sa Ss mo a uae iNT NT REAL REAL REAL REAL REAL REAL REAL REAL This card generates and meshes a NURBS surface from the specified control points Parameters I The order p of the B zier curve in the direction The range is 1 lt p lt 4 where p 1 is linear 2 quadratic and so on I gt The order q of the B zier curve in the direction 1 lt q lt 4 This line is followed by p 1 lines with the node names of q 1 control points in the fields S to Sq 1 as many of the 5 column fields as required A surface that is linear in the direction and quadratic in the t direction would for example require three lines NU 1 2 AA AB AC BA BB BC It is possible to create a triangular Nurbs surface In this case all control
95. surfaces are used to reduce the loss of numerical accuracy due to a finite number of decimal digits at low frequencies These special basis functions are known as loop and star basis functions FEKO tests for numerical accuracy and responds with warning 594 If the standard FEKO version does not give warning 594 the use of LFFEKO is normally not required LFFEKO is activated by means of the EG card in the pre input file see description of the EG card in section 8 2 12 Only metallic objects may be present in the input file the use of wires and dielectric bodies is not possible The use of symmetry is likewise also not possible in the current version PO and UTD are also not allowed Since wires are not allowed excitations such as Al A2 and A3 cannot be used In addition to the pre file LFFEKO requires a geo file 12 2 The pre input file The input file with the extension pre is a normal input file for PREFEKO except that in the EG card see description of the EG card in section 8 2 12 the parameter LFFEKO has to be activated See the above description of the limitations 12 3 The geo input file The input file with the extension geo serves the purpose of manually changing the loop order as well as to take sections of the geometrical structure For the correct solution of the scattering problem the number of unknown variables in the matrix equation has to be corrected if closed or connected surfaces are present Des
96. that of the surrounding medium such as coaxial cables filled with dielectric material one needs to reduce the length of the transmission line Losses in the transmission line network due to the shunt admittances or transmission line losses directly are taken into account and will for instance reduce antenna efficiency or gain The TL card is used in example_39 Examples Guide to create a log periodic antenna EM Software amp Systems S A Pty Ltd December 2002 THE OPTIMISER OPTFEKO 10 1 10 The optimiser OPTFEKO 10 1 Description With optimising certain properties should be improved by changing a number of specified parameters For example the gain property of an antenna can be optimised by varying the parameters of the geometry Certain parameters are allowed to be varied within certain bounds and are called the optimising parameters As discussed in section 6 3 the program PREFEKO can handle symbolic variables Therefore the input file pre can be created using symbolic variables to represent the optimisation parameters Apart from defining the optimisation parameters the aim or goal of the optimisation must be specified An aim function is used to determine how well the current solution approximates the desired goal The aim function can for example be defined such that its minimum is the optimum solution A number of different optimisation methods are available with OPTFEKO The program OPTFEKO requires two input fi
97. the external problem are written to the output file The currents of the internal problem are different to those of the external problem only in that their sign is reversed If requested by the DA card a os card will be created in addition to the currents written to the output file 2To use the CableMod interface this module must be activated if required please contact EMSS EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 83 9 2 36 PS Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S PS2 PS3 PS4 NON EFF IE REAL REAL REAL REAL REAL REAL REAL REAL This card is used to control program execution Parameters PS2 0 Normal execution 1 The matrix elements are calculated and stored in a mat file 2 The matrix elements are read from a mat file rather than calculated 3 Ifa mat file exists from a previous calculation the matrix is read from this file Otherwise the matrix elements are calcu lated and saved in a mat file PS3 0 Normal execution 1 The currents are calculated and stored in a str file 2 The currents are read from the str file i e the calculation of the matrix elements and the solution of the matrix equation are skipped 3 If a file str exists from a previous calculation the currents are read from this file Otherwise the currents are calculated and saved in a str file for later use PS4 The expansion coefficients of the MoM
98. the following antenna parameter quantities e S_11 the reflection coefficient S in a Zo ohm system S11 is calculated from with Zo the specified impedance of the feed line If Subt Z_load is checked as discussed above Zin Zin Zo else Zin Zn S11 e VSWR the standing wave ratio The VSWR is calculated from 1 S41 VSWR 1 Si1 with S11 as calculated above e Eff the antenna efficiency This is the efficiency of the antenna as calculated by FEKO For a zero loss ideal antenna this is 100 at each frequency but for more realistic antennas with losses the efficiency is a function of frequency e Z_in the antenna input impedance This option plots the input impedance Zin As before if Subt Z_load is checked Zin Lim Zo else Zin Z where Z is the input impedance calculated by FEKO with impedance loading included e Y_in the antenna input admittance Plot the input admittance The loading treatment is the same as for Z_in e P_rad the radiated power of the antenna The power radiated from the antenna is plotted as calculated by FEKO It is dependent on the input power as well as the efficiency and mismatch of the antenna December 2002 FEKO User s Manual 5 8 THE PROGRAM GRAPHFEKO For S11 Zin and Yin one may plot the real and imaginary parts as well as the magnitude and phase or any combination of these components The other parameters are all positive real values and one
99. the line and write these to a isd file for further processing by CableMod The isd file also contains additional data required by Ca bleMod for example the frequencies that were used during the solution The complete geometry without the transmission line as well as the frequency and excitation Ax cards must be defined in FEKO 11To use the CableMod interface this module must be activated if required please contact EMSS EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 47 9 2 20 CO Card A 6 10 15 20 25 30 40 50 60 70 80 90 100 110 LAB DO N CDICKE CMUER CEPSR CSIGMA CRHO CTAND CTAND OV MUE EPS A IE REAL REAL REAL REAL REAL REAL REAL REAL This card specifies a dielectric or magnetic coating of wire segments or triangle elements The coating applies to all calculations following the CO card Parameters LAB All segments or triangles with this label are coated DOCOVR 0 No coating present as if the relevant label has no CO card 1 Coated wires using the Popovic formulation are used see description below 2 Coated wires using the volume equivalence theorem are applied see description below 3 Electrically thin multilayer dielectric magnetic coating on surface triangle elements 4 Multilayer dielectric magnetic coating on surface triangle elements N Number of layers This field is only applicable for coatings on triangle elements for wires only one layer is perm
100. the required number of processes This option is only supported on UNIX 11 4 1 TIMEFEKO output TIMEFEKO generates different pre files at the different frequencies The out files for all these runs are available if TIMEFEKO was called without the r option These results are summarised if they are requested in the pre file in ost triangle currents oss segment currents cur the currents on voltage sources far far fields nfe near electric fields and nfh near magnetic fields In each case the results for each frequency is listed one after the other with frequencies separated by a line containing a single character The time domain results are given in the aus file for all outputs requested in the pre file Currents are requested by the OS card Note that requesting the current on a large number of structures will result in very large aus files 11 5 A TIMEFEKO example In figure 11 7 an ideal conducting metallic cube with side lengths of 1m is shown The current in the middle of the front side the scattered field from the direction of incidence the incident wave travels in the negative x direction as well as the excitation pulse are to be calculated The input file cube pre is reproduced below These files are located in the examples utils timefeko subdirectory of the FEKO installation TIMEFEKO example pre file A metallic cube with side lengths im Only 1 8 of the cube is generated
101. the triangles are displayed e Surface The triangle surfaces are displayed With Flat selected a true represen tation of the triangulated geometry is displayed Background removes any colours from the display of the surfaces of the triangles Smoothed represents a smoothed display of the triangulated geometry e More Tf the model contains anisotropic dielectric layers specified with the SK card the More button becomes visible This opens a new panel where one may select an SK card and the layer number to show the fibre principle direction of the layer Under Cuboids select e Lines Outlines of the cuboids are displayed e Surface Cuboid surfaces are displayed Under Polygons select e Lines Outlines of the UTD polygons are displayed e Surface Polygons surfaces are displayed December 2002 FEKO User s Manual 3 26 THE PROGRAM WINFEKO 3 5 6 2 Geometry Previous display options Select this item to go back to the previously active display options panel It would be more efficient to use the speed button associated with this command see section 3 4 3 3 5 6 3 Geometry FEK display options On selection of this item the FEK file display options panel is activated Labels associated with the fek file are presented in the Available Labels list Note See comments on the Apply OK and Cancel buttons in section 3 5 5 7 To display only selected labels copy the appropriate labels to the Selected Labels list u
102. to medium So S3 No special meaning input field must just be occupied and not empty December 2002 FEKO User s Manual 8 64 DESCRIPTION OF THE GEOMETRY CARDS All triangles and segments before a ME card represent metallic structures in free space This is also the case when an input file does not have a ME card When for example the surface current method is used to generate a dielectric sphere which shall represent in this example medium 1 in free space the following card form is used DP A 0 0 0 0 0 0 DP B 0 0 0 0 1 0 DP C 1 0 0 0 0 0 ME 1 0 KU A B C 0 0 0 0 0 180 0 360 0 The normal vectors of the sphere point outwards see KU card section 8 2 22 from medium 1 dielectric to medium 0 free space More detail can be found in example_04 and example_23 Examples Guide As an illus tration consider the basic geometry of example_23 as shown in figure 8 35 and consists of a dielectric cone medium 1 mounted on top of a metallic cylinder AO Dielectric cone Medium 0 Metallic Mediumi cylinder Figure 8 35 Example of a dielectric cone on top of a metallic cylinder to demonstrate the use of the ME card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 65 There are three types of triangles involved e Metallic triangles in free space Medium 0 on the bottom and side of the cylinder e Metallic triangles also forming the border surface of the dielectr
103. used then the following data block is given DATA OF THE DIELECTRIC CUBOIDS No xl inm yl inm z inm rel permittivity label x2 in m y2 inm z2 in m conductivity in S m x3 inm y3 inm z3 in m mass density in kg m m m x4 inm y4 inm z4 in m loss factor tan delta 1 0 0000E 00 0 0000E 00 0 0000E 00 4 0000E 00 O 3 3333E 01 0 0000E 00 0 0000E 00 0 0000E 00 0 0000E 00 3 3333E 01 0 0000E 00 1 0000E 03 0 0000E 00 0 0000E 00 3 3333E 01 0 0000E 00 2 0 0000E 00 0 0000E 00 3 3333E 01 4 0000E 00 O 3 3333E 01 0 0000E 00 3 3333E 01 0 0000E 00 0 0000E 00 3 3333E 01 3 3333E 01 1 0000E 03 0 0000E 00 0 0000E 00 6 6667E 01 0 0000E 00 Each cuboid is given a consecutive number The x y and z corner points coordinates are given in the first three columns The first row is the reference point The second row is the corner point to which from the reference point the first basis function is defined Further the third and fourth rows define the next two basis functions with respect to the reference point In the last column the relative dielectric constant e followed by the conductivity o in as well as the density of the cuboid in xe In each dielectric cuboid there are three basis functions in each coordinate direction one The data of these basis functions is given in the following format DATA OF THE BASIS FUNCTIONS FOR DIELECTRIC CUBOIDS Symmetry information No cuboidno direc yz XZ xy status 1 1 1 28 55 109 unknown 2 2 1 29 56 110 unknown 3 3
104. wave x Define the variables r 1 Radius of the sphere betrad 1 Electrical size of the sphere epsr 15 The relative dielectric constant maxlen 0 7 The maximum edge length Define segmentation parameters IP maxlen The corner points DP A 0 0 0 DP B 0 0 tr DP C tr 0 0 Select the medium ME 1 0 December 2002 FEKO User s Manual 6 6 THE PREPROCESSOR PREFEKO Generate an eighth of the sphere KU A B C 0 0 90 90 maxlen Use symmetry in all three coordinate planes yz plane ideal electrically conducting plane xz plane ideal magnetically conducting plane xy plane only geometrically symmetric SY 1 2 3 1 End of the geometry EG 1 0 0 0 0 Assigning the dielectric s properties DI epsr 1 3 0 Incident plane wave excitation freq betrad c0 2 pi r FR a 0 freq AO 0 1 1 1 0 0 0 180 0 Near fields along the z axis FE 1 1 25 0 0 0 0 0 1 98 0 0 0 0 0 04 FE 4 1 1 50 0 0 0 0 0 0 98 0 0 0 0 0 04 FE 1 1 1 25 0 0 0 0 0 1 02 0 0 0 0 0 04 End EN The use of variables makes the investigation of structures with varying geometry e g variable distance of the antenna in front of a reflector an easy process because only one variable needs to be changed It also allows FOR loops and IF conditions 6 4 FOR NEXT loops Some cards in FEKO implicitly use loops such as when an FR card with multiple frequen cies is used This however does not a
105. 0 3 2 End of the geometry 1 0 1 0 0 Set the frequency 1 0 freq Excitation by means of an incident plane wave 0 1 al 1 0 0 0 90 0 0 0 0 0 Surface current density output for surface with label 1 4 1 1 Calculate the far field only in the direction of incidence 2 End For this example we have chosen a Gaussian pulse excitation with a 3 x 10 As discussed in section 11 3 2 f34g is approximately 56 MHz such that we require at a maximum frequency of at least 224 MHz We select a maximum frequency of 250 MHz The time shift selected for this example is 6 light metre and the structure dimensions is of the order of 1 metre Thus we believe that the time response should die out within 40 light metre or 133 ns Then equation 11 8 then yields N 34 EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM TIMEFEKO 11 11 The tim input file cube tim then contains Timefeko Example tim file Define the Pulse form GAUSS Parameters of the Gaussian pulse Time shift Exponent 2 0e 8 3 0e 8 Define the frequency block Gaussian pulse with a 3 0e 8 1 s i e _3dB 0 187 a 56 2 MHz x Choose f_max gt 4 f_3dB 224 9 MHz use f_max 250 MHz Total time we want to analyse T 40 lightmetres 133 4 ns i e N 1 T f_max 34 FREQUENCY Upper frequency Number of Samples 250 0e 06 34 Normalise the time to that of the speed of light NORM Output the excitation EXCITATION The follo
106. 00 51882462221e 005 0 00000000000e 000 42849147499e 005 0 00000000000e 000 07906709346e 005 0 00000000000e 000 10609464655e 005 0 00000000000e 000 46284430530e 004 0 00000000000e 000 56160952549e 004 0 00000000000e 000 37768474311e 003 0 00000000000e 000 67653919004e 003 0 00000000000e 000 78441744890e 002 0 00000000000e 000 45400653850e 002 0 00000000000e 000 92614320231e 002 0 00000000000e 000 40179442097e 001 0 00000000000e 000 EM Software amp Systems S A Pty Ltd x m y m z m 5 55556E 02 5 55556E 02 JX JY 00000000000e 000 3 80396548298e 009 2 00000000000e 000 3 29242237538e 009 1 00000000000e 000 2 60940425868e 009 1 00000000000e 000 4 56971413492e 009 9 00000000000e 000 2 25486652232e 009 7 00000000000e 000 4 83790802156e 009 1 00000000000e 000 2 80525051677e 010 1 x m y m z m 1 11111E 01 1 11111E 01 JX JY 00000000000e 000 1 18216923283e 008 1 00000000000e 000 9 02561817670e 010 1 00000000000e 000 1 28360949904e 008 1 00000000000e 000 4 46200189557e 009 9 00000000000e 000 4 91955007365e 009 8 00000000000e 000 9 27286771090e 010 1 00000000000e 000 3 59541937732e 009 1 JZ 65565071677e 007 93726675808e 006 37480675066e 006 30586425956e 007 87315697551e 007 35885783156e 006 63413481451e 006 JZ 93459474753e 007 95358888266e 006 34406393148e 006 71500429087e 007 71581870796e 007 21262288818e 006 49801053069e 006 December 2002 THE PROGRAM TIMEFEKO n
107. 01 4489e 001 0142e 001 9600e 000 oono PUNE m o pb Hi OrrrrrrreNKDNNYNN m N December 2002 0000e 001 0776e 001 2898e 001 71879e 001 7102e 001 9224e 001 2121e 001 9612e 001 0672e 001 8163e 001 7775e 001 8835e 001 Target ct 1538e 000 0386e 000 0007e 000 0176e 000 1202e 000 2145e 000 0740e 000 1914e 000 1658e 000 1970e 000 2171e 000 2225e 000 Penaltyfct 0 0 0 0 0 0 0 0 0 0 0 0 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 other spec 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 0000e 000 PRRERRRRR RR Ree converges for 7 1538e 000 7 0386e 000 7 0007e 000 7 0176e 000 7 1202e 000 7 2145e 000 7 0740e 000 7 1914e 000 7 1658e 000 7 1970e 000 7 2171e 000 7 2225e 000 FEKO User s Manual 10 20 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 DNNNNWDADADAAAGTANANKFPHBPANDWDANOAWAWN y 7953e 000 6133e 000 7780e 000 1247e 000 1333e 000 5423e 000 5510e 000 3777e 000 9686e 000 7953e 000 2043e 000 71867e 000 4643e 000 6688e 000 1732e 000 0865e 000 2910e 000 5822e 000 9210e 000 5232e 000 7754e 000 3187e 000 4643e 000 0666e 000 1927e 000 9938e 000 7 7
108. 02 FEKO User s Manual 9 38 DESCRIPTION OF THE CONTROL CARDS e Sector radiator We want to realise an ideal sector radiator which radiates 10 Watt horizontal polar isation in the angular region defined by 70 lt gy lt 70 and 75 lt Y lt 105 Since the angle range of the imported pattern must be positive one may define separate sources for the regions 0 lt y lt 70 and 290 lt p lt 360 A more elegant solution is to define a single pattern in the range 0 lt py lt 140 and rotate it by 70 around the z axis The complete radiation pattern is be defined in the following input file note that only horizontal polarisation i e El Fis required Application example for the AR card Sector radiator No other structures considered EG 1 o 0 0 0 Set the frequency FR 1 0 100 0e6 Specified radiated power PW 1 10 0 Define the sector radiator AR 0 3 2 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 10 Theta Phi E_theta E Phi 75 0 0 0 dl 0 105 0 0 0 1 0 75 140 0 0 1 0 105 140 0 0 1 0 Check Compute the full 3D radiation pattern with 5 deg stepping FF 1 37 73 0 0 0 0 0 5 0 5 0 End EN FEKO determines a directivity of 10 1 dBi The radiation pattern is easily validated by calculating the far field as shown with the FF card in the last step The result as presented by WinFEKO is shown in figure 9 15 Z Figure 9 15 3D radiation pattern of the sector radiatior EM Software amp Sys
109. 1 FEKO runs in a restricted LITE mode see the Getting Started manual FEKO_HOME This variable is set to the FEKO installation path which contains the subdirectories such as bin doc license and for the parallel version mpi FEKO_MACHFILE The parallel version of FEKO is started by running RUN FEKO with options np x When FEKO is installed on a parallel computer or a computer cluster the configuration of the cluster and the number of processes that should be run on each computer is specified during the installation This can can be overwritten for any FEKO run by creating a so called machines file and setting the environment vari able FEKO_MACHFILE to point to this file More detail can be found in section 7 2 FEKO_MACHINFO If this parameter is set FEKO will write information about the machine precision to both the screen and the output file FEKO_MPISTATISTICS This environment variable provides additional information about the performance of the parallel version of FEKO There are three options 1 Give a detailed report of the CPU and run times for the individual processes It is for example possible to determine how much time each process required during the computation of the array elements 2 Give as additional output the MFLOPS rate of each process without network communication time This is useful to determine the relative performance of nodes in a heterogeneous cluster 4 Give information about the network perform
110. 1 line segments see segments linear set of equations 9 43 load subtract in GraphFEKO 5 6 5 16 load data in GraphFEKO 5 1 5 4 in WinFEKO 3 5 loading 9 94 an edge 9 76 attachment point 9 74 distributed 9 75 impedance 9 79 microstrip line 9 76 parallel circuit 9 77 series circuit 9 78 log in GraphFEKO 5 20 losses 9 85 low frequencies 12 1 LP card 9 77 LS card 9 78 LZ card 9 79 1 5 magnetic cuboids 8 18 magnetic dipole 9 17 magnetic fields calculating 9 54 plotting in GraphFEKO 5 14 magnetic ring current 9 13 magnitude in GraphFEKO 5 19 main display options 3 4 3 23 maxalloc m 2 12 2 13 maximum constants 2 12 2 13 ME card 8 63 medium dielectric 8 63 8 86 magnetic 8 86 memory allocation 2 12 releasing 3 7 3 11 requirements for WinFEKO 3 1 meshing 2 4 non uniform 8 6 8 8 8 11 rules 2 4 multilayer substrates defining 9 67 display 3 26 multiple reflections 8 81 multiply results in GraphFEKO 5 19 near fields animation 3 20 calculating 9 54 calculation offset 9 80 contour plots 3 18 display 3 5 3 24 iso surfaces 3 5 3 16 ortho slices 3 5 3 18 plotting 3 16 5 2 5 14 pointing vector 3 16 network parameters 3 5 3 14 5 8 display in GraphFEKO 5 2 networks 9 94 neu file display 3 4 3 10 3 27 new project 3 6 nodes defining 8 20 definition 2 4 display 3 23 variable names 6 9 8 20 non uniform mesh 8 6 8 8 normal vectors 8 17 displa
111. 1 30 57 111 unknown 4 4 1 31 58 112 unknown In the first column the consecutive number of the basis function is given The next column indicates the number of the cuboid The column direction indicates the direction of the basis function in the respective cuboid 1 indicates that e g the basis function is defined from the reference point to the second corner point The last four columns contain information concerning the symmetry properties of the cuboid where the structure and the meaning is the same as with the other basis functions December 2002 FEKO User s Manual 14 6 DESCRIPTION OF THE OUTPUT FILE OF FEKO Thereafter information follows regarding the number of basis functions DATA FOR MEMORY USAGE Number of metallic triangles 0 max triangles MAXNDR 0 Number of dielectric triangles 0 Number of metallic segments 0 max segments MAXNSEG 0 Number dielectr magnet cuboids 64 max cuboids MAXNQUA 64 Number of metallic edges MoM O unknown O max edges MAXNKA 10 Number of metallic edges PO O unknown 0 Number of dielectric edges MoM 0 unknown 0 Number of nodes between segments 0 unknown 7 max nodes MAXNKNO 10 Number of connection points O unknown O max conn MAXNV 15 Number of dielectric cuboids 64 unknown O max cuboids MAXNQUA 64 Number of basis funct for MoM 192 unknown 48 max basisf MAXNZEILE 227 Number of basis funct for PO O unknown O max basisf MAXNKAPO 0 Memory requirem
112. 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 INT INT INT INT INT STR STR STR STR STR With this two line card an impressed current source is specified The current varies linearly between the value at the start point and that at the end point see figure 9 9 Figure 9 9 Impressed line current with a linear current distribution Parameters ANFL 0 New excitation replaces all previous excitations 1 Additional excitation add to previous excitations EIR1 Amplitude J in A of the current at the start point 7 EIR2 Phase of the current at the start point in degrees EIR3 x coordinate of the start point 7 in m Note that all the coordinate values are scaled by the SF card if SKALFLAG 1 EIR4 y coordinate of the start point 7 in m EIR5 z coordinate of the start point 7 in m EIR12 Amplitude 72 in A of the current at the end point Fa EIR2 2 Phase of the current at the end point in degrees EIR32 x coordinate of the end point 72 in m see comment for EIR1 EIR42 y coordinate of the end point r in m EIR52 z coordinate of the end point 7 in m EIR62 This parameter is optional If specified and different from zero this value gives a finite wire radius for the impressed current element FEKO then assumes that the current is uniformly distributed on the wire surface and uses the exact wire integral If the parameter EIR6_2 is not specified the current filament approximation is used This value is scaled by th
113. 3 5 6 6 Geometry Advanced visibility The Advanced visibility panel is activated when this item is selected Note See the comments on the Apply OK and Cancel buttons in section 3 5 5 7 The Size of dipole points controls the size of point dipole sources The Shrink cells as well as Enlarge radius options are available for Segments and Im pressed Currents Use the appropriate slide bars to set the length of the segment display When set to 100 each line segment is displayed with its full length The default is 90 The 90 setting makes the individual line segment identification easier Use the Enlarge radius slide bars to enlarge the radius of the segment or impressed current display This is an artificial enlargement used for display purposes only and has no effect on the solution When set to 1 each line segment is displayed with its actual radius as defined by the user this is the default When set to between 2 and 100 each line segment is displayed with its actual radius enlarged by the enlarge factor This is useful when visualising thin wire segments and impressed current line elements 3 5 6 7 Setup Requested fields Used to view the positions at which near and far fields will be calculated as requested by the user with the FE and FF cards Note See the comments on the Apply OK and Cancel buttons in section 3 5 5 7 Note further If the checkbox next to the Requested Fields caption is checked then the panel is
114. 5 If GraphFEKO is already running with the correct out file selected rather use the Im port Receiving antenna Rx menu item in GraphFEKO to load the receiving antenna data 3 5 5 6 Far fields 2D plot On selection of this item GraphFEKO starts automatically selects the current project out file and loads the far field data if it exists The Far fields panel in GraphFEKO is also activated automatically Select this item to load and display far field data such as gain directivity RCS etc For further information see section 5 Note that every time this item is selected from within WinFEKO the program Graph FEKO will be executed If GraphFEKO is already running with the current project out file selected rather use the Import Far fields menu item in GraphFEKO to load the far field data EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 15 3 5 5 7 Far fields 3D polar plot On selection of this item the far field data is loaded from the current project output file and the 3D radiation patterns panel in WinFEKO is activated The far field data is displayed in 3D together with the model geometry Right click on the pattern to display information associated with the pattern at the point of selection on the rendering scene Note If any options are changed on the 3D radiation patterns panel either the Apply or OK button must be clicked for the changes to take effect The Apply butto
115. 5e 005 Result destination vector ttalpha 6 9209918e 000 7 8159398e 001 Minimal value of the aim function at no 31 of the last analysis 38 no EM Software amp Systems S A Pty Ltd 7 2283000e 000 7 2218e 000 7 2150e 000 7 1728e 000 7 1769e 000 7 2205e 000 7 2053e 000 7 2270e 000 7 2282e 000 7 2214e 000 7 2218e 000 7 2255e 000 7 2207e 000 7 2281e 000 7 2268e 000 7 2266e 000 7 2266e 000 7 2274e 000 7 2262e 000 7 2283e 000 7 2279e 000 7 2279e 000 7 2277e 000 7 2281e 000 7 2279e 000 7 2282e 000 7 2282e 000 PRRERRRRRRPRRRRR RR BRP BRR RPP BP e December 2002 THE PROGRAM TIMEFEKO 11 1 11 The program TIMEFEKO 11 1 Description With the program TIMEFEKO electromagnetic scattering problems can be solved in the time domain It is based on the program FEKO that does the calculation in the frequency domain and an FFT algorithm that transforms the data to the time domain For the excitation a number of different pulses have been defined and stored in the function library The functions available at present are described in section 11 3 1 The program TIMEFEKO is constructed in such a way that all the data in the output file out from FEKO are transformed i e in the input file the cards have to be specified in the correct way to ensure that the correct data is transformed Information on the correct card definitions is given in the following section The program TIMEFEK
116. 6 EN card 9 53 end of geometry 8 23 end of input file 9 53 environment variables 2 15 3 2 equivalent aperture 9 27 excitation see sources 9 5 display 3 24 3 29 13 EXIT command 6 9 export graph data 5 4 far fields 2D plots 3 5 3 14 3D plots 3 5 3D polar plots 3 15 calculating 9 63 plotting 5 2 plotting in GraphFEKO 5 12 fast rotation 3 23 FE card 9 54 feed see sources fek file display 3 4 3 11 3 26 FEKO 7 1 running from WinFEKO 3 4 3 11 FEKO_USER_ HOME environment variable 2 15 3 2 FEKO_WRITE environment variable 2 15 FEMAP mod file creation 3 6 running from WinFEKO 3 4 3 10 FF card 9 63 field selection 3 4 files 9 50 input 2 1 output 14 1 summary of 2 2 find element 3 4 3 29 FEMAP element 3 29 flat display triangulated surfaces 3 25 FO card 8 28 Fock area 8 28 FOR NEXT loops 6 6 FR card 9 65 13 1 frequency 9 65 adaptive sampling 13 1 gain plotting in GraphFEKO 5 12 general comments 2 1 general settings options 3 31 geometry display 3 24 entering 2 4 8 31 geometry cards 2 1 8 1 83 BL 8 4 BP 8 6 BQ 8 8 BT 8 11 CB 8 13 CL 8 14 CN 8 17 DK 8 18 DP 8 20 DZ 8 21 EG 8 23 EL 8 26 FO 8 28 HE 8 29 IN 8 31 IP 8 47 KA 8 49 KK 8 50 KL 8 55 KR 8 56 KU 8 60 LA 8 62 ME 8 63 NU 8 67 PB 8 71 PH 8 73 PM 8 78 PO 8 81 PY 8 84 QU 8 86 SF 8 88 SU 8 90 SY 8 91 TG 8 92 TO 8 95 TP 8 98 UT 8 99
117. 7 The program FEKO 7 1 LLE o AA IE 7 1 Te o A 7 1 7 2 1 Running the sequential version 7 1 7 2 2 Running the parallel version lt 7 2 December 2002 FEKO User s Manual iv CONTENTS 8 Description of the geometry cards 8 1 8 1 Overview of the geometry cards o o 8 1 8 2 Alphabetical description of the geometry cards 8 3 A A abd thd ewan da obd de oS bs 8 3 Bee Eb Gers oy pp 22294 oe eee RE ER RE REDS SERS 8 4 bee BPC cios 8 6 Boe BOM coccion RA A 8 8 Roe ETONE O we PRE RS 8 11 Roe CD aed 2 be ee eA EEE A E E 8 13 E ieee ee ee a wee 8 14 dar Oi eS lt cocos aaa EA 8 17 Bee DECS 2 044 6 24s sss eh he eee heed ooo ak x 8 18 A MAA bE Be GREE ES 8 20 COD seca hha GE oe aces Se So ek be eee 8 21 B212 EG Cad 2 2 6c eee arrada deete hee t irete 8 23 Ble EL Ctd occ id ee ee aa a a a a 8 26 Bold FO Catd socorro e ee SE 8 28 8215 HE Cad soo eete a eee bed be ee bee a 8 29 Sal UN Cai cias a arta 8 31 E AA 8 47 Sade KAO oia ada 8 49 LEAL Kier oi AAA E hee Bae 8 50 A ee A a a u i a a a E ee 8 55 OFER ORN soseri na ede ek a E 8 56 Ral EUC cc o AA 8 60 T22 LA Cade EE 8 62 Bett ME Cad ocras aaa ee ia bbe a pa aa eS 8 63 Sao UR a a A 8 67 alo PRC ociosas ooo a aw ores 8 71 EM Software amp Systems S A Pty Ltd December 2002 CONTENTS A A 8 2 28 PM Card oo ccs c4dadeesdcnddbbadabowe O20 PO Oul ok ho ioe Pani oeed hb deed elas 8230 PY Card 26 es oko ween db
118. 8 to clipboard 3 8 vector based 3 9 priority setting 7 1 program configuration loading 3 31 saving 3 31 program execution control 9 83 project management 3 3 PS card 9 83 PW card 9 85 PY card 8 84 QU card 8 86 quadrangle 8 8 radiation input file templates 3 6 patterns 9 63 patterns as sources 9 34 ray paths in WinFEKO 3 22 real ground 9 41 9 67 real part in GraphFEKO 5 19 receiving antenna 3 5 3 14 5 10 display in GraphFEKO 5 2 requested field display 3 24 3 28 resistance loading 9 75 9 78 results 3 5 checking validity 2 18 extracting from output file 3 13 rotation 8 92 around arbitrary selected point 3 30 of point 8 98 WinFEKO speed buttons 3 5 S parameters 3 14 5 8 9 93 S11 3 13 3 14 5 6 S21 3 14 5 8 SAR calculations in WinFEKO 3 16 plotting in GraphFEKO 5 14 save as UNIX 4 1 graph 5 1 5 2 graph data 5 1 5 4 project 3 3 3 7 WinFEKO options 3 31 scaling 8 88 8 92 scattering input file templates 3 6 plotting in GraphFEKO 5 12 searching for element 3 4 segmentation parameters 8 47 rules for 2 4 segments 8 4 arc 8 14 coating 9 47 creation see geometry cards definition 2 4 display 3 25 3 28 helix 8 29 selecting picking geometry 3 30 results 3 30 selection far field data 3 15 geometry and results 3 4 of current data 3 21 of near field data 3 18 SF card 8 88 SK card 9 89 skin effect 9 89 Smith chart 5 6 5 7 smooth surface d
119. AD mesher tool FEMAP This method is preferred for very complex geometries or for importing data from other CAD pack ages The meshed geometry is then exported from FEMAP and imported by PREFEKO 1The UTD implementation is currently limited to an arbitrary number of perfectly conducting flat polygonal surfaces or one perfectly conducting circular cylinder December 2002 FEKO User s Manual 1 2 INTRODUCTION Note that PREFEKO also supports the direct import of meshed geometry in NASTRAN and AutoCAD dxf formats For simpler geometries the commands processed by PREFEKO are much more efficient In addition to controlling the solution process WinFEKO is used to visualise the geometry created by FEMAP PREFEKO The output file out of FEKO contains all the solution information The resulting fields and or currents can be displayed in 3D with WinFEKO or as 2D graphs using GraphFEKO Note that the preprocessor PREFEKO and the field computation program FEKO are available on PC s and a wide variety of workstations The programs WinFEKO Edit FEKO and GraphFEKO are available on PC s only All pre and post processing must thus be performed on a PC while the actual computationally intensive field calculations can be performed on the PC itself or on a workstation or parallel cluster as required First time users are advised to work through the Getting Started manual located in the doc directory under the FEKO home directory the direct
120. AG x filename ext LABEL LABEL_END scaling where the integer parameter FLAG specifies the type of file The filename is speci fied within quotation marks and may contain directory names as well for example IN myfiles include inc Both and are allowed on Windows and UNIX systems These parameters are required for all file types Label selection LABEL and LABEL_END are optional integer parameters If they are not present the entire model is included If only LABEL is present only structures with this label will be included If both fields are present all structures with labels in the range LABEL to LABEL_END inclusive will be imported Note that layers properties tags in the model files are all converted to FEKO labels See the description for the different file types below Typical examples here for FEMAP neutral files are IN 1 part_i neu IN 1 part_2 neu 5 IN 1 part_3 neu 7 9 The first line will include all structures in the FEMAP model the second only those on layer 5 and the last line all structures on layers 7 8 and 9 FEMAP layers are converted to FEKO labels Label selection is not supported for pre Concept and STL files Type selection The type selection flag x is optional for certain input formats FEMAP ASCH NASTRAN AutoCAD PATRAN and is required for Concept models For pre and STL files it is not supported This parameter allows selecting only certain types of structures where the paramete
121. Adjust the 3D pattern size using the slide bar under Blob settings Select the Close blob option to close a 3D pattern in the phi direction e g if far field data has been calculated for phi 0 to 355 the 3D pattern will start at phi 0 and stop at phi 360 if the Close blob option has been selected Also under Blob settings are three edit boxes which can be used to move the Origin of the 3D pattern to an arbitrary point Enter the x y and z coordinates in metres and hit the Apply button for the origin shifting to take effect With a vertex or geometric entity selected see 3 5 7 4 the Select Entity button becomes enabled Click this button to fill the x y and z coordinate point edit boxes with the coordinates of the selected entity Unselect the Elt direction option in the Main display options panel if a 3D pattern colour display is obviously asymmetrical The 3D patterns and model geometry can be made visible invisible by selecting unse lecting the 3D pattern and Geometry options in the Main display options panel December 2002 FEKO User s Manual 3 16 THE PROGRAM WINFEKO 3 5 5 8 Near fields 2D plot On selection of this item GraphFEKO starts automatically selects the current project out file and loads the near field data if it exists The Near fields panel in Graph FEKO is also activated automatically Select this item to load and display near field data such as electric field E magnetic field H power density S
122. CII file With I gt 2 the data is read from lines J3 to 3 I4 I5 1 of the specified external data file Each line contains 6 space delimited data fields in the following order The angle Y in degrees The angle y in degrees Amplitude of the field strength EZF in V Phase of the field EJ in degrees Amplitude of the field strength En F in V Phase of the field Eee in degrees The inner loop should be with respect to the angle Y such that the order of the lines is as follows Y P va P Ya p Un p v p2 va p2 OT Pl EM Software 4 Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 37 e I gt 3 pattern is specified in the pre file The case Jz 3 is similar to reading an external data file I2 2 except that the data is read directly from the pre input file The six data fields mentioned for Iz 2 must appear in the columns of the parameters R to Re in the ly I5 lines following the AR card The data lines may be separated by comment lines EditFEKO however does not support this and FOR NEXT loops may be used An example is given below The radiation pattern specified in the local spherical coordinate system V y of the antenna is read and initially placed at the origin of the global coordinate system in which the pre file is constructed The pattern is now rotated by an angle a parameter Rg around the z axis by ay parameter R7 around the y axis and by az
123. DOCOVR 0 tan delta_mu 0 000E 00 conducting After the calculation of the currents the losses that result from finite conductivity are displayed POWER LOSS in Watts in the segments Label skineffect ohm loss distr load coating 2 0 0000E 00 0 0000E 00 0 0000E 00 0 0000E 00 total 0 0000E 00 0 0000E 00 0 0000E 00 0 0000E 00 in the triangles skineffect ohm loss 5 4620E 07 1 7386E 08 5 4620E 07 1 7386E 08 Total loss in the segments 0 0000E 00 W Total loss in the triangl 5 6359E 07 W Loss total 5 6359E 07 W Efficiency of the ant 99 9877 In the first column the label is displayed the lowest row displays the sum December 2002 FEKO User s Manual 14 12 DESCRIPTION OF THE OUTPUT FILE OF FEKO 14 5 Near field If the near field is calculated the following data is displayed medium LO X m O 0 00000E 00 0 00000E 00 O 1 00000E 01 0 00000E 00 O 2 00000E 01 0 00000E 00 O 3 00000E 01 0 00000E 00 VALUES OF THE ELECTRIC FIELD STRENGTH in V m total field incident and scattered CATION Y m Z m magn 1 00000E 00 1 00000E 00 1 00000E 00 1 00000E 00 EX EY va phase magn phase 6 70088E 01 99 86 7 65636E 01 166 42 6 46235E 01 74 23 1 14589E 00 166 13 6 23014E 01 47 98 1 55289E 00 165 83 5 99908E 01 21 51 1 95743E 00 163 95 EZ magn phase 6 89061E 01 126 74 7 17685E 01 98 76 7 35678E 01 70 70 7 41473E 01 42 30 Displayed are the position as well as the ind
124. EAL REAL REAL REAL REAL REAL REAL REAL With this command the already entered geometric elements triangles segments etc can be translated rotated and or scaled It is also possible to duplicate structures Parameters I For 1 0 the geometry that has been created up to where the TG card is entered is translated rotated and or scaled The number of triangles and segments remains the same For J not equal to zero the values represents the number of new structures to be generated e g for 3 and R3 90 an antenna can be rotated 3 times around the z axis so that there will be a total of 4 antennas The total number of segments and triangles will now be the number that was present before the TG card multiplied by 1 1 L gt T3 Labels can be used to select a certain part of the structure see also selection with the parameter I5 that is to be rotated translated or scaled The TG card will be applied only to those parts of the struc ture whose label lies within the range Ig lt label lt Is see LA and CB cards I Each newly generated structure will be assigned a label that is incre mented by 4 from that of the original structure An exception is the label 0 which is retained Is Selection of the structure that is affected by the rotation translation and or scaling This applies to 0 All structures already entered metallic dielectric triangles metallic segments dielectric magnetic cuboids wedges and edges in PO regio
125. EKO will give a warning if this is the case Note that for a perfect electrical ground FLAGRF 2 conducting structures such as segments or triangles cannot be electrically connected to the ground plane If this is required the ground plane should be realised with electrical symmetry SY card A dielectric ground real earth can only be used with bodies treated with MoM PO or the hybrid MoM PO i e the hybrid MoM UTD method cannot be used in the presence of a real ground EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 43 9 2 18 CG Card A 6 10 15 20 25 30 40 50 60 70 80 90 100 110 CGM MAX PC BCG BLO PREC SEL IT LAGFLAGCKN TE NT R NT NT REAL REAL REAL REAL REAL REAL REAL REAL Here the method used to solve the matrix equation may be chosen Parameters CGMSEL Gauss Elimination according to LINPACK is used The CGM Conjugate Gradient Method is used The BCG Biconjugate Gradient Method is used Iterative algorithm with band matrix decomposition Gauss elimination according to LAPACK is used Qn Wr OO The block Gauss algorithm is used in case the matrix has to be saved on the hard disk 7 CG using PIM parallel iterative methods 8 Bi CG using PIM 9 CGS using PIM 10 Bi CGSTAB using PIM 11 RBi CGSTAB using PIM 12 RGMRES using PIM 13 RGMRESEV using PIM 14 RGCR using PIM 15 CGNR using PIM 16 CGNE using PIM 17 QMR usi
126. FEKO User s Manual Suite 4 0 FEKO 45 154 PREFEKO 26 1 53 and later December 2002 Copyright 1998 2002 EM Software amp Systems S A Pty Ltd 32 Techno lane Technopark Stellenbosch 7600 South Africa MM Tel 27 21 880 1880 Fax 27 21 880 1936 rr E Mail feko emss co za FEN WWW http www feko info CONTENTS 1 Contents 1 Introduction 1 1 2 General comments 2 1 2 1 Structure of the input fille o 2 1 22 Ppummary the files 22s ee ee e e a a ae a 2 2 23 Entering the geometry ooo ee eae ae ek 2 4 2A Utilisation symiitiry 6 6 6 ew ee bbb eh Sb e 2 7 2 4 1 Geometric symmetry 2 00002 0008 2 7 ZA2 Blsotrie symmetry o o sse sioa na eee ea RRR ee 2 7 2 4 3 Magneticsymmetry o o por nand ere a ee 2 8 2 4 4 Example of the application of symmetry 2 8 2 4 5 Special enforcement of symmetry Even odd method 2 10 Zo Dielbciriesolids 04 265 4 bb de seem ee a a k ioa a 2 11 2 6 Dynamic memory management 2 12 2 6 1 Setting maxalloc for out of core solutions 2 12 2 6 2 Other variables that are under user control 2 13 2 6 3 Variables that are automatically set correctly 2 13 2 7 Environment variables co cocoa aoa 00506660644 e 2a 2 bes 2 15 2 8 Checking the validity of the results 2 18 3 The program WinFEKO 3 1 3 1 Hardware and software requirements for WinFEKO 3 1 3 1 1 Operatin
127. IPTION OF THE CONTROL CARDS 9 3 In the first format the two excitations are processed one after the other for each frequency The cards are executed in the order FR Ax Ax FR Ax Ax EN where the second FR indicates execution of the frequency loop for the second specified frequency In the second format the first excitation is treated for both frequencies before treating the second excitation for both frequencies Here the cards are executed as FR Ax FR Ax FR Ax FRAx EN For the computational requirements one finds that in the first case the matrix elements have to be calculated twice it have to be completely recalculated each time the frequency is changed and in the second case four times The computation time is not only influenced by the control cards but also by what has to be solved for In the following example the structure has to be solved at a number of frequencies and for the ideal conducting and non ideal conduction with losses cases FR FR card for multiple frequencies FE calculation of the near fields SK include skin effect FE calculation of the near fields EN end of the input file The three control cards FE SK and FE are written to the buffer and are worked through in the loop for the different frequencies At the first frequency the FE card initiates the field calculation Because a SK card has not yet been read ideal conductivity is assumed Then the SK card is read and losses are taken int
128. L REAL REAL REAL REAL REAL This card can be used to generate a part of a parabolic reflector as shown in figure 8 39 S Figure 8 39 Sketch illustrating the use of the PB card Parameters S Name of the centre of the paraboloid S2 Name of a point at any distance and perpendicular to the base plane and above the centre point S3 Name of a point on the outer edge of the paraboloid but on the base plane S4 Name of a point in the direction S1 S2 with respect to point S3 and on the edge of the paraboloid R The angle in degrees subtended by the arc of the parabolic reflector R Maximal edge length of the triangles along the outer edge of the arc in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used The radius R of the paraboloid is derived from the distance between the points S and S3 as can be seen in figure 8 39 The height is determined by the distance between points S and S3 The focal point f is determined by R far 4h December 2002 FEKO User s Manual 8 72 DESCRIPTION OF THE GEOMETRY CARDS Example of PB card usage The parabolic reflector as shown in figure 8 40 can be generated by using the following lines is U rFUuUQw St Bere OO Figure 8 40 Example for the PB card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 73 8 2 27 PH Card 1 6 10 15 20 25 30 40 50 60 70 80
129. L REAL REAL REAL REAL REAL REAL REAL Here the discrete circuit elements in parallel as shown in figure 9 27 can be assigned to a segment Rp Cp Figure 9 27 Sketch of the parallel circuit Parameters LAB All segments with this label are assigned the parallel circuit values specified below RP Value of the resistor in Q LP Value of the inductor in H CP Value of the capacitor in F The impedance is then given by 1 AA ae ek Cy Rp ia qe If RP 0 then the resistance is interpreted as infinite i e in the parallel case it will not change the impedance The same applies to LP The LP card may be combined with the LD LS LZ and the SK cards but only one LP card may be used per label If a second LP card is used it replaces the values entered by the first one This card has no significance for surface elements even when these are assigned the same label December 2002 FEKO User s Manual 9 78 DESCRIPTION OF THE CONTROL CARDS 9 2 32 LS Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 ILS LAB RS LS cs INT NT R NT NT REAL REAL REAL REAL REAL REAL REAL REAL Here the discrete circuit elements in series as shown in figure 9 28 can be assigned to a segment Rs Ls Cs Figure 9 28 Sketch for the serial combination Parameters LAB All segments with this label will be assigned the elements in the series combination RS Value of the resistor in Q LS Value of the inductor in H CS Value of the capacitor i
130. O 0 1000 CH Figure 8 17 Example for the DZ card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 2 12 EG Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 PS1 PS5 NO MEJUSE EPSENT EPSR MUER SIGMA TAND TAND CHE PHOQEDG CK INT INT INT INT I NT STR STR STR STR STR MUE EPS 8 23 REAL REAL REAL REAL REAL REAL REAL REAL This card indicates the end of the geometrical input It is essential that this card is used Parameters PS1 0 1 gt 1 PS5 1 NOCHECK 0 WMETHOD _ 0 December 2002 The geometric data of the segments and surface elements is written to the output file but not to any additional files No geometric data is written reducing the output file size When PS1 gt 1 a bitwise and is used as follows 1 write geometry information to the out file 2 write geometry information to a NASTRAN file 4 write geometry information to a STL file For example geometry output to out NASTRAN and STL files is requested with PS1 7 NASTRAN only is requested with PS1 2 No messages are sent to the standard output device usually the screen Warnings errors and messages that indicate the program s progress are sent to the standard output device Warnings errors and explicit messages about the program s progress are sent to the standard output device This option is useful during program development
131. O 5 2 5 8 5 10 5 11 on segments 3 14 3 21 5 11 on surface elements 3 21 selection 3 4 curved arc 8 14 cutplane display 3 23 options 3 4 3 27 cylinder 8 108 dielectric 8 21 UTD region 8 101 DA card 9 50 DI card 9 52 dielectric 2 11 8 63 9 52 cuboid cylinder 8 21 cuboids 8 18 8 86 sphere 9 67 thin sheet 9 89 diffraction theory 8 99 dimension scaling 8 88 dipole aperture array 9 27 directivity plotting in GraphFEKO 5 12 disc 8 56 discrete elements 9 77 9 79 display axis 3 23 currents 3 5 fek file 3 4 3 11 multilayer substrates 3 26 neu file 3 4 3 10 options 3 4 for fek file 3 26 for neu file 3 27 WinFEKO 3 1 3 23 requested field points 3 4 distributed load 9 75 DK card 8 18 DP card 6 9 8 20 dynamic memory management 2 12 DZ card 8 21 edges definition 2 4 edit graph 5 16 EditFEKO 4 1 card editor 4 2 edit menu 4 5 file menu 4 1 keystrokes 4 7 OPTFEKO mode 4 6 options menu 4 2 parameter suggestion 4 4 running from WinFEKO 3 4 3 10 searching 4 6 superuser mode 4 2 variables 4 5 effective gain plotting in GraphFEKO 5 12 efficiency 9 85 EG card 8 23 EL card 8 26 electric fields calculating 9 54 plotting in GraphFEKO 5 14 elements 8 11 creation see geometry cards display 3 25 display direction 3 23 display numbers 3 23 search for 3 29 ellipsoid 8 26 elliptical hole 8 73 ELSE statement 6 8 EM properties display 3 2
132. O The superuser mode in FEKO is only used during program development and is not available to the general user Thus it is not recommended to use EditFEKO in the superuser mode If the user tries to edit an existing card containing superuser parameters EditFEKO will also prompt the user and switch to superuser mode The FEMFEKO mode is only useful for developers working on the FEKO FEM hybrid Tf the Sort drop down list menu item is selected the contents of suggestion boxes the response to clicking the right mouse button over an an input field dialog box are sorted alphabetically If not they appear in the order they are created See also section 4 2 2 The OPTFEKO editor mode will accept both English and German keywords and it will retain the existing language when editing blocks The Options menu allows the user to select the language for newly created control blocks in the opt file 4 1 3 Window menu This menu presents the standard Windows functionality to arrange or select the editor windows on the main editor area 4 1 4 Help menu This menu presents the version of EditFEKO About and presents a shortcut to the User s Manual The shortcut requires that some or other PDF viewer such as the Adobe Acrobat reader is associated with pdf files 4 2 PREFEKO mode 4 2 1 Generating input cards Cards can be entered and edited directly in the editor window In most cases the user would call one of the card editors by clicking o
133. O User s Manual 9 56 DESCRIPTION OF THE CONTROL CARDS e FELKOR 0 Cartesian coordinates 2 y 2 Zz A x y Figure 9 18 Field calculation in the near field FELKOR 0 Observation Point x r Y z Unit vectors of the coordinate system 1 0 0 f 0 y 1 Z 1 0 0 0 EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 57 e FELKOR 1 Cylindrical coordinates around z axis r p z Zz A Figure 9 19 Field calculation in the near field FELKOR 1 Observation Point r cosy r rsinp z Unit vectors of the coordinate system cos Y sin p 0 F sing p COS Y 10 0 0 1 December 2002 FEKO User s Manual 9 58 DESCRIPTION OF THE CONTROL CARDS e FELKOR 2 Spherical coordinates r p Zz A Figure 9 20 Field calculation in the near field FELKOR 2 Observation Point r sin cos p r rsinvsiny r cosv Unit vectors of the coordinate system sin Y cos p cos cos Y siny r sinvsiny v cosvsing p cosy cos Y sin Y 0 EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 59 e FELKOR 3 Cylindrical coordinates around the x axis r p x Z A vs x y Figure 9 21 Field calculation in the near field FELKOR 3 Observation Point x r rcosp r sin p Unit vectors of the coordinate system 0 0 1 r cosy p siny Z 0 sin Y cosy 0 December 2002 FEKO User s Man
134. O uses two input files that have to be created by the user 11 2 The pre input file The input file with extension pre is the normal input file for PREFEKO in which the frequency has to be expressed symbolically While the program TIMEFEKO is running the frequency is constantly changed TIMEFEKO generates new pre files in which the actual numerical value of the frequency is assigned The user may use the DEFINED function to assign a numerical value to the frequency variable freq in the pre this is useful for running PREFEKO and viewing the geometry in WinFEKO see section 11 5 The FR card must use the frequency variable freq The number of frequencies to be examined must be one NFREQ 1 Example Set the frequency FR 1 freq In the input file pre all the desired output parameters in their respective cards must be set for example FF card FE card OS card Only the data in the output file out can be transformed Note The program TIMEFEKO does not check the pre file Special care should be taken to ensure that the segmentation parameters for the required frequency interval are fine enough for the program FEKO see IP card section 8 2 17 If they are not strictly adhered to the program can terminate with an error message December 2002 FEKO User s Manual 11 2 THE PROGRAM TIMEFEKO It is also possible to vary the segmentation for certain applications far field near field to save memory and com
135. OF THE GEOMETRY CARDS 8 51 R4 0 The normal vector of the generated triangles points to the outside 1 The normal vector of the generated triangles points to the inside Rs If this parameter is empty or is set to 1 a cone with a circular cross section is created The parameter Rs may be used to generate a cone with an elliptical cross section within reasonable limits Rs gives the ratio of the ellipse s two half axes where a is the distance S1 53 It is recommended to generate elliptical cones with extremely small or extremely large axial ratios with a CAD system such as FEMAP as the distortion formulation used in PREFEKO may fail in these cases The fineness of the mesh on the shell s surface is determined by the maximum edge length specified by the last IP card prior to the KK card Along the arcs accurate modelling of the geometry may require finer segmentation and the values Ra and Rg specify the maximum edge length along the corresponding arcs R3 is only used when a truncated cone is created If either of these values is not specified the length specified with the IP card will be used on the corresponding arc First example of KK card usage Using the following command the conical shell in figure 8 24 is created OK IP 0 35 DP A 0 0 0 0 0 0 DP B 0 0 0 0 2 0 DP C 1 0 0 0 0 0 KK A B Cc 360 0 0 3 EG EN Second example of KK card usage Using the following command the conical shell in figure 8 25 is created
136. QF must be empty it will be calculated as shown below for FREQF 2 NFREQ Maximum number of discrete frequency points in this frequency band at which FEKO may be executed limitation to avoid convergence problems If left empty the default value of 1000 will be used I gt This field is only relevant when the CM card is used to create a isd file The results are written to the isd file at Is discrete frequencies I4 This field is only relevant when the CM card is used to create a isd file It then specifies the type of frequency stepping of the discrete frequencies written to the isd file 0 The discrete frequencies differ by a constant increment 1 Successive frequencies are related by a constant factor December 2002 FEKO User s Manual 9 66 DESCRIPTION OF THE CONTROL CARDS FREQO Starting frequency in Hz DFREQ In order to obtain a continuous frequency response the adap tive frequency interpolation technique obtains the solution at a set of discrete frequency points They are automatically placed for example using large frequency increments in regions with a smooth behaviour of the results and much finer frequency in crements close to resonances Sometimes for example when us ing a frequency dependent mesh it can happen that the FEKO results versus frequency are not exactly continuous To avoid that the adaptive algorithms gets stuck at such small discon tinuities and tries to refine more and more it will st
137. R OPTFEKO 10 17 DP P1 0 0 0 0 0 0 DP P2 0 0 lambda 2 0 0 DP P3 0 0 lambda 2 lambda 2 DP P4 O 0 0 lambda 2 x a lambda lambda 4 sin rad alpha z lambda 4 cos rad alpha DP A x 0 0 z z 0 45 seglen DP B a 0 0 tz DP C a 0 0 z Define a quarter of the plate in the quadrant y gt 0 and z gt 0 BP Pi P2 P3 P4 Mirror the plate around the plane y 0 xz plane ideal magnetic wall sy 1 0 3 0 Create the upper half of the dipole antenna without feed segment The default label 0 is still in use BL A B Mirror in the plane z 0 xy plane ideal electric conducting plane sy 1 0 0 2 Create the feed segment with the label 1 LA 1 BL B C End of the geometric input EG 1 0 0 0 0 Set the frequency cO is the speed of light in vacuum freq c0 lambda FR 1 freq Excitation by means of a voltage gap E field at a node Al 0 1 1 0 0 0 Calculate the far field FF 1 1 0 90 0 0 0 0 0 0 0 x End EN As a first step a discrete search is done by systematically varying the two optimisation parameters to find the region of the minimum December 2002 FEKO User s Manual 10 18 THE OPTIMISER OPTFEKO The opt file is as follows Input file for the optimiser OPTFEKO for a bent dipole in front of a reflector Define optimisation parameters Name Begin value Minimum Maximum ttalpha 80 80 80 ta 0 25 0 25 2 0 Select the optimisation method di
138. S e Layered dielectric sphere GFFLAG 1 2 4 5 6 With this option it is for example possible to analyse a cellphone in front of a shell model of the human head very efficiently Parameters GFFLAG 1 2 4 5 6 I5 0 1 Green s function for a homogeneous dielectric sphere at the origin of the coordinate system is used Green s function for a homogeneous dielectric sphere that has been coated with a dielectric and is situated at the origin of the coordinate system Green s functions for a homogeneous dielectric sphere which consists of a core and three dielectric layers at the origin of the coordinate system As when GFFLAG 1 a Green s function for a homogeneous dielectric sphere at the coordinate origin is used but in con trast to GFFLAG 1 metallic structures can be present in the inner parts of the sphere Green s function for homogeneous dielectric sphere at the origin of the coordinates which consists of a core and 2 lay ers Metallic structures are allowed inside the sphere Use of interpolation gfe and gfh files to accelerate the computations No interpolation used Rs Convergence criteria for the summation of the rows of Green s functions If Rs is 0 or undefined a sensible standard criterion is used AZ Figure 9 24 Example of a sphere with 3 layers GFFLAG 6 EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS for
139. S The label assigned to all segments triangles etc defined in cards following this one a positive number in the range 0 to 99999 In order to select the position of the feed Ax cards the location of impedance loading LD LS LP and LZ cards or structures on which to apply the skin effect SK cards each segment triangle etc is assigned a label Other applications include the selective transformation or copying of parts of geometry TG card and outputting of currents on selected elements OS card Labels are also used to define triangles on which to apply physical optics PO card All elements etc that are created after the LA card e g by a BP card are assigned the value S as label A different label is only assigned by a new LA card All structures created before the first LA card or if no LA card is present is assigned the default label which is 0 8 The definition Ax stands for any of the control cards AO Al A2 EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 63 8 2 24 ME Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 A A IE REAL REAL REAL REAL REAL REAL REAL REAL When solving the fields in dielectric objects by means of the surface current method this card can be used to distinguish the different media or to create segments and metallic triangles within the dielectric Furthermore this card is used to switch between the generation o
140. S4 0 The normal vector of the generated triangles point to the outside i e away from the centre of the sphere 1 The normal vector point to the inside centre of the sphere Ri The begin angle va in degrees of the spherical segment R The begin angle pa in degrees of the spherical segment R The end angle J in degrees of the spherical segment R The end angle pe in degrees of the spherical segment Rs The maximum length of the triangles along the curved edges in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used A complete sphere may be created with the parameters Va Pa 0 Je 180 and Pe 360 Example of KU card usage Using the following commands the spherical segment in figure 8 34 is generated IP DP DP DP KU EG EN gt awe e OO D O O OG OGOGO O O W a B Cc 60 0 90 0 80 0 270 0 0 25 EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 61 S Direction p 0 Figure 8 33 Sketch illustrating the use of the KU card Figure 8 34 Example for the KU card December 2002 FEKO User s Manual 8 62 DESCRIPTION OF THE GEOMETRY CARDS 8 2 23 LA Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S e ae SAR NE INT REAL REAL REAL REAL REAL REAL REAL REAL With this card labels are assigned to segments triangles polygons cuboids UTD cylin ders and points Parameters
141. The A7 card is supported only for compatibility with FEKO input files that were created before the AE card became available Parameters ANFL 0 New excitation replaces all previous excitations 1 Additional excitation add to previous excitations ULA A triangle with the label ULA is searched for The excitation is placed on the edge that lies opposite to the first corner of the triangle Once again the label must be unambiguous i e if possible only one triangle must have this label If there is more than one triangle with this label then only one will be fed Alternatively one may set ULA 1 then the feed edge is determined by specifying its Cartesian coordinates EIR3 y EIR4 and z EIR5 The edge must be an internal edge i e it must not lie on the edge of a surface except when connected to a PEC ground plane or UTD plate EIR1 Absolute value of the voltage Uo in V EIR2 Phase of the voltage Up in degrees EIR3 If ULA 1 the x coordinate of the edge centre in m EIR4 If ULA 1 the y coordinate of the edge centre in m EIR5 If ULA 1 the z coordinate of the edge centre in m The values EIR3 EIR4 and EIR5 are scaled by the SF card if SKALFLAG 1 If two triangles are connected to the edge the basis function between these triangles is excited The vector direction of the voltage source lies in the same direction as the basis function associated with this edge This is the direction of the current flow through the edge The i
142. The quadrangle shown in figure 8 44 is created with the lines xx discretisation IP Oral define some points DP A 0 0 0 DP B 1 0 0 DP C 0 8 0 7 0 DP D 0 2 0 6 0 DP E 0 4 0 0 the plate with hole PH A B C D E 0 6 EG EN EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 77 Figure 8 44 Example of a quadrangular plate with an elliptical hole Fourth example of PH card usage If the point D above corresponding to 3 is not used the triangle in figure 8 45 is created using 0 1 m maximum edge length define some points DP A 0 0 0 DP B 1 0 0 DP D 02 0 6 0 DP E 0 4 0 0 the plate with hole PH A B D E EG EN Figure 8 45 Example of a triangular plate with a spherical hole December 2002 FEKO User s Manual 8 78 DESCRIPTION OF THE GEOMETRY CARDS 8 2 28 PM Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 AM BM gIC Mc D Mp 15 EMg FMp GMg IE REAL REAL REAL REAL REAL REAL REAL REAL This card defines by specifying the corner points a polygonal plate which must be meshed into triangles Concave corners are allowed A sketch is shown in figure 8 46 The user can also specify a smaller or larger mesh size along certain edges D A Figure 8 46 Sketch illustrating the use of the PM card A maximum of 13 corner points are allowed The points are connected in the order in which they are entered in the PM card Concave corners are allowed T
143. UZ 8 101 VS 8 103 WG 8 106 ZY 8 108 GF card 9 67 14 GraphFEKO 5 1 clear file data 5 6 data extraction 5 2 edit menu 5 16 file control 5 1 file menu 5 2 help 5 21 import menu 5 5 line arithmetics 5 19 load import data 5 4 running 3 5 5 1 save export data 5 4 templates 5 3 toolbars 5 1 tools menu 5 19 version information 5 21 window menu 5 20 graphics cards with WinFEKO 3 2 graphs arithmetics 5 19 5 20 Green s functions 9 67 ground plane 9 41 display 3 24 hardware rendering 3 2 HE card 8 29 helix 8 29 help WinFEKO 3 33 Hertzian electric dipole 9 16 hide structure using cutplane 3 27 hot keys EditFEKO 4 7 WinFEKO 3 2 3 23 IF statement 6 8 imaginary in GraphFEKO 5 19 impedance 9 79 loading 9 76 microstrip fed 9 76 Smith chart 5 7 import data in GraphFEKO 5 4 import geometrical data 8 31 impressed line current 9 20 9 25 9 39 display shrinked cells 3 28 enlarge radius 3 28 IN card 8 31 incident plane wave 9 8 include files 8 31 inductance loading 9 75 9 77 9 78 input file 2 1 IP card 8 47 iso surfaces near fields 3 5 3 16 isometric view 3 5 KA card 8 49 KK card 8 50 KL card 8 55 KR card 8 56 KU card 8 60 L4 card 9 74 LA card 8 62 label selected calculation 9 80 labels 8 13 8 62 display 3 4 3 26 layer display 3 27 LD card 9 75 LE card 9 76 lead lines display 3 23 legend display 3 23 LFFEKO 12
144. VR 3 electrically thin coating on surface triangles This option allows the user to add multilayer dielectric magnetic coatings on surface elements with label LAB The layers may have different permittivity and perme ability but the total coating must be electrically i e relative to the wavelength in the coating as well as geometrically see the requirements below thin e DOCOVR 4 dielectric magnetic coating on surface triangles This option allows electrically thick dielectric magnetic coatings on surface elements with label LAB Here it is only required that the total coating must be geometrically thin i e it must be thin relative to the triangle size and thus also to the free space wavelength as well as the radius of curvature of the surface This option may only be applied to elements treated with PO Note that for DOCOVR 1 or 2 no surface triangles with element LAB are allowed Likewise with DOCOVR 3 or 4 no segments with label LAB are allowed If DOCOVR 4 is used it must remain consistent for the whole FEKO run Thus one may not have DOCOVR 4 for on some triangles for one solution and then add DOCOVR 4 to other triangles or remove it from some previously coated triangles for any subsequent run It is however allowed to change the thickness and the medium parameters of the coating If a scaling factor SF card is present it affects both the thickness CDICKE and the wire radius CRHO December 2002 FEKO User s Manual 9 50
145. Windows Metafile wmf 3 5 1 7 List of previous projects Below the Printer setup item is a list of previous projects Select one of these to quickly open one of the projects recently worked on December 2002 FEKO User s Manual 3 10 THE PROGRAM WINFEKO 3 5 1 8 Exit Select this item to exit WinFEKO On exit the winfeko ini file is updated for use when WinFEKO is executed the next time 3 5 2 Preprocessing menu Used for the various preprocessing functions and module executions required before the FEKO solver can be started 3 5 2 1 Run FEMAP Select this item to start the CAD mesher FEMAP FEMAP is started with the mod file associated with the current project For example if the current project name is dipole FEMAP is started with the file dipole mod if such a file exists in the current project directory path If not FEMAP is started with the default FEMAP startup settings untitled file The FEMAP environment variable must be set to the correct directory path for FEMAP to start successfully from the WinFEKO environment This should have been done auto matically by the WinFEKO installation program See the Getting Started manual The user can also execute another 3rd party CAD packages of his choice using this menu item The path and extension of such a package must be specified by the user under the General Settings options see section 3 5 8 1 3 5 2 2 Display FEMAP neu If a neutral file neu has been cre
146. a from the FEKO output file see section 5 A basic description of WinFEKO is presented in this chapter See the Getting Started manual to get an introduction to using FEKO and all the utility modules including WinFEKO 3 1 Hardware and software requirements for WinFEKO 3 1 1 Operating systems WinFEKO has been developed for the MS Windows 95 98 ME and NT 2000 XP envi ronments It has been our experience that the OpenGL libraries used for visualisation in WinFEKO were more stable under Windows NT 2000 XP than under 95 98 ME On clusters of PCs running MS Windows NT 2000 XP the parallel version of FEKO is started from WinFEKO see section 3 5 4 This uses MPICH NT which requires Windows NT 2000 XP for all the machines in the cluster and the PC where the job is started from even if the this PC does not form part of the parallel cluster 3 1 2 Memory requirements It is recommended that at least 64 MByte RAM are available on the system more memory would be required for large models and data sets Ensure that a large enough swap file exists on systems with 64 MByte RAM or less 3 1 3 Display settings WinFEKO can be used with 256 colours but a colour setting of at least 16 bits is re commended for effective visualisation The development of WinFEKO was done for a 800x600 screen resolution A higher resolution may be used but a lower resolution is likely to give trouble December 2002 FEKO User s Manual 3 2 THE PROGRAM WINFEKO
147. a ground plane has been specified the calculation of the far fields below the ground plane is not possible Observation points with z lt 0 will thus be ignored EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 65 9 2 26 FR Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 REQ 73 Za FREQO DFREQ FREQE RE F ae ae uae NT NT REAL REAL REAL REAL REAL REAL REAL REAL This card sets the frequency in Hz at which the solution will be obtained This may be a single frequency or a loop of discrete frequencies linear or multiplicative stepping One can also obtain a continuous solution in a given frequency band with adaptive frequency interpolation If this is used only one FR card is allowed Parameters FREQF 0 Loop using discrete frequency points Consecutive frequen cies differ with DFREQ i e the new frequency value will be the value of DFREQ added to the previous value 1 Loop using discrete frequency points The frequencies differ by the factor DFREQ i e the new frequency is DFREQ times the previous value 2 Use an adaptive frequency interpolation technique to obtain a continuous representation of the results in the given fre quency band for FREQF 0 or 1 NFREQ Number of frequencies to be examined FREQO Starting frequency in Hz DFREQ The frequency increment in Hz or the multiplication factor when FREQF 1 FREQE Optional ending frequency in Hz If this is specified DRE
148. a plate with a concave corner which one might also define with two BQ cards as shown in figure 8 47 note the finer mesh along the edges from B to C and C to D Example for the PM card meshed polygon DP DP DP DP DP DP H m I awe NN Rh POO O O O O O RROOOORrp ooounno IP 0 2 PM A B 0 D E F EG EN The above indicates that everything should be on a single line with the first 0 1 starting in column 131 A F D E Figure 8 47 Example for the PM card December 2002 FEKO User s Manual 8 80 DESCRIPTION OF THE GEOMETRY CARDS Second example of PM card usage The commands below generate a plate with three specified internal mesh points as shown in figure 8 48 Note that there are node points at Q1 Q2 and Q3 Example for the PM card meshed polygon with internal points ok External boundary points of the polygonal plate 0 1 DP Pi 0 1 DP P2 1 2 DP P3 1 5 DP P4 0 3 DP P5 0 3 ok Internal mesh points DP Qi 0 5 DP Q2 1 0 0 DP Q3 0 7 Mesh the plate IP 0 PM Pi P2 P3 P4 1 P5 Qi Q2 Q3 EG EN 0 La T 0 0 0 0 0 0 o Figure 8 48 Example for the PM card with internal mesh points EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 81 8 2 29 PO Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 PO OS PO PO PO R3 Ra SAVE LAB ADE SYMNOC MAX VIS LAG UPL REFL A IE REAL REAL REAL REAL REAL REAL REAL REAL
149. a smooth colour representation without discontinuities 1 The averaging that may be very time consuming particu larly for structures containing a large number of triangles are switched off LABOS2 When DOOS is 6 or 7 this specifies the end of the label range If the parameter DOOS 0 is specified no currents are extracted but the solution is started if required With DOOS 4 only the currents associated with certain elements specified with the label LABOS can be extracted If e g all the currents on the triangles or segments with the labels 0 and 4 are to be extracted then the following two cards may be entered 0s 4 0 0s 4 4 December 2002 FEKO User s Manual 9 82 DESCRIPTION OF THE CONTROL CARDS The options DOOS 5 and DOOS 6 permit the creation of a rsd file for use with the transmission line simulation program CableMod The currents along all for DOOS 5 or selected segments DOOS 6 are exported to the rsd file the filename without extension is the same as that of the fek file The rsd file is an ASCII file and contains first a description of the geometry of the line followed by blocks with the current information for each frequency It can be read by CableMod and can also be imported back into FEKO to realise an impressed line source see the AC card If the current of dielectric triangles surface current formulation must be output by the OS card both the equivalent electric and magnetic surface currents of
150. ace currents scaling will become active Click the Animation button The Animation control panel is activated This is a modal panel and the Close but ton must be clicked before control is given back to the main WinFEKO window For detailed information on the options and settings on the Animation control panel see section 3 5 5 11 3 5 5 13 UTD rays Select this item if a FEKO problem involving UTD regions has been solved with the option to save the ray file On selection the data in the ray file is loaded if available see UT card section 8 2 38 and the Ray display options panel is activated The rays data is displayed on the model geometry Note 1 Ray files can quickly become very big which will make the display of the rays very slow If more than 4000 ray lines are identified in the ray file a warning appears Select Yes to continue loading all ray data and No to display only the first 4000 rays data already loaded and disregard the rest of the data in the ray file Note 2 See comments on the Apply OK and Cancel buttons in section 3 5 5 7 Select or unselect the Display ray file info to switch the display of the ray file infor mation on or off Click the Clear ray file button to release the memory and associated data allocated for the ray file information Under Visibility select the ray information that should be displayed One can select the type of rays to display and determine the maximum number of refl
151. after the EG to define points for use in the AP card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 99 8 2 38 UT Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 I I2 73 Ja 55 R A IE REAL REAL REAL REAL REAL REAL REAL REAL With this command the parameters for the geometric theory of diffraction UTD for the polygonal surfaces are defined Parameters I The parameter J UTDFLAG determines whether the classical GTD by Keller 4 0 or whether the uniform diffraction theory UTD by Kouyoumjian J 1 should be used It is advisable to always use the UTD 1 1 because singularities appear on the shadow boundaries in Keller s approach I gt The parameter I2 UTDMAXRX gives the maximal number of ray interactions i e reflection and diffraction combined With for exam ple J2 3 a ray can have 3 reflections or 2 reflections and a diffraction For 12 0 only direct rays are taken into account Iz For I3 1 a debug file extension dbg is generated This file con tains large amounts of information and should only be used when debugging With 3 0 no debug file is generated I4 For I4 1 the ray information is exported to the bof and to a special ray file so that the ray paths can be displayed in WinFEKO The ray information can become very large and thus it should only be exported if specific ray paths are to be examined For J4 0 no ray information is exporte
152. age Using the following commands the toroidal segment which is shown in figure 8 54 is generated IP DP DP DP DP TO EG EN O O O OOOO 35 0 360 0 gt U0Q0u gt oo0oo0or oO NNOOO Figure 8 54 Example for the TO card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 97 Second example of TO card usage The commands below generates the toroidal segment with an elliptical cross section as shown in figure 8 55 example of an elliptical torus IP 0 7 DP A 0 0 0 0 0 0 DP B 0 0 0 0 1 0 DP C 1 0 0 0 0 0 DP D 1 0 0 0 0 2 TO A B C D 90 0 360 0 0 2 0 15 0 2 0 EG EN Figure 8 55 Example for the TO card with an elliptical cross section Rg is specified December 2002 FEKO User s Manual 8 98 DESCRIPTION OF THE GEOMETRY CARDS 8 2 37 TP Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 I2 I3 Ri R2 R3 R4 R5 Re R7 INT ae ae ae E REAL REAL REAL REAL REAL REAL REAL REAL With this card points previously defined with the DP card can be translated rotated and or scaled Parameters I gt All points with labels in the range Ig lt label lt Js are translated rotated or scaled The parameter gt specifies the start label Is The end of the label range I Each transformed point will be assigned a label that is the label of the original point incremented by I4 The exception are points with label 0 their label is not incremented it re
153. ailable when a plane wave incident field is used as excitation e RCS is the radar cross section The radar cross section as calculated by FEKO This option is only available with a plane wave incident field as excitation and if the appropriate far field calculations have been requested see FF card Plotting the far field data as a function of angle If a single frequency is selected the user can select between Y and y as independent variable The selected quantity will be plotted as a function of this value over the full available range The input box for this value changes colour and shows the range A single value must then be selected for the second variable Plotting the far field data as a function of frequency Some far field quantities can be plotted as a function of frequency if more than one frequency solution is available The Independent variable under Plot options will change to Freq range when a range of frequency values in the frequency block is selected This can be done by clicking and dragging over the required frequency range December 2002 FEKO User s Manual 5 14 THE PROGRAM GRAPHFEKO S polarisation Z polarisation Horizontal pol Vertical pol eg eg Figure 5 1 Polarisation of the electric far field as viewed at a fixed position in the direction of propagation 5 3 2 9 Near fields When this item is selected GraphFEKO loads the near field data if it exists from the selected FEKO output fi
154. allel version of FEKO if it is available in the installation is used in the solution The parameter x specifies the required number of processes This option is only supported on UNIX Information on the optimisation process is stored in a log file with the extension log in the example above the filename will be dipole log 10 5 An example using OPTFEKO In figure 10 1 a dipole antenna in front of a reflector is shown The gain is to be optimised The bent angle a of the dipole and the distance a between the dipole and the reflector are given as optimisation parameters The input file dipole pre for this geometry is as follows Optimisation Example A bent dipole antenna with variable distance in front of a square reflector December 2002 FEKO User s Manual 10 16 THE OPTIMISER OPTFEKO AAA Figure 10 1 Bent dipole in front of a reflector The optimisation parameters are created by OPTFEKO Here we check if they have been defined using the defined function and define them such that we can run PREFEKO while working with this file if not defined Hta then a 0 25 lendif 11if not defined alpha then alpha 30 lendif Remaining parameters lambda 1 seglen lambda 10 segrad lambda 1000 side_l lambda 5 Set the segmentation parameters IP segrad side_l seglen Define points EM Software amp Systems S A Pty Ltd December 2002 THE OPTIMISE
155. also used of course if the problem requires more memory than is available in both RAM and virtual memory For solutions which do not fit into the available RAM but do fit into the RAM plus virtual memory the user should set maxallocm to inform FEKO on the amount of available RAM in MByte Note that one should reserve some memory for the operating system and other running applications For example if a big problem must be executed on a PC with 512 MByte of RAM maxallocm should be set to about 460 MByte This is done with the line maxallocm 460 anywhere in the pre file preferably near the start For parallel versions of FEKO this memory limit applies to each process The following is a list of the variables which the user might occasionally set for special purposes such as the in core limit described above maxallocm This sets the maximum allocatable memory in Mbytes For example the definition maxallocm 400 will allow a maximum of 400 MByte of memory to be allocated If this is not enough the matrix will be saved to the hard disk or the program will be halted For parallel versions of FEKO this memory limit applies to each process Note that if maxallocm is used it will have preference and maxalloc will be ignored if it is used in the same pre file EM Software amp Systems S A Pty Ltd December 2002 GENERAL COMMENTS 2 13 maxalloc This sets the maximum allocatable memory in bytes For example the definiti
156. also with 10 increments In this case the aperture increases in size in both directions when TYPE is negative A fully closed surface can be created by specifying 6 planar apertures or a spherical one The surface equivalence principle can be applied to this surface by reading both electric and magnetic fields for each plane For planar apertures the user should specify 6 AP cards which each use both electric and magnetic fields If separate cards are used for the EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 31 Z 2 9 Jer l Y ee a 3 ane p gt 4 X d o Figure 9 13 Location of the equivalent dipoles on a spherical aperture a Positive TYPE b Negative TYPE electric and magnetic fields the radiated power is not calculated correctly The normal vector must point to the exterior region normally this is outward For planar apertures created form efe and hfe files the sample order determines the directions of s and g which in turn determines the normal vector n s x tg If this is pointing into the cube an additional 180 phase shift is obtained by setting PHASE 180 This change the sign of the field radiated by the aperture which when interacting with the remaining sources will result in the correct total fields in the desired region All surfaces and scatterers inside the body must be removed and those outside retained For
157. alue of the iso surface An iso surface represents a surface of equal magnitude in a 3D data set Iso surface calculations for large sets of 3D data needs intense processing and could take some time even on relatively fast systems A hint is to select the required quantity and component Wait until the extent and default iso surface value have been calculated slide bar and edit box under Iso surface settings will be updated Then select a relatively high iso value before hitting the Apply button The iso surface calculation should be relatively fast except in the case of the phase component Now set the iso surface value smaller to the required value The available Near field quantity can also be selected The Pointing vector S is only available when both E and H fields have been calculated at the same positions with one FE card SAR is only available if the near electric fields in dielectric regions have been calculated See end of this section for more detailed discussion on SAR calculations EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 17 Under Component select mag phase or instantaneous from the list and one or more of the Cartesian components x y and z Currently WinFEKO can only extract iso surfaces for near fields calculated in the Cartesian coordinate system With E_field and mag selected y E Ey Ez is plotted or any combination of the three components depending on the choice of
158. ame way as is the case without the IN card The data of the segments triangles and polygonal plates are given in an ASCII file formatted as shown below There is no need to adhere to specific columns the data fields merely have to be separated by one or more spaces nk nd ns np nt x 1 y1 z 1 String_name x 2 yQ z 2 String_name x nk y nk z nk String_name EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 35 d1 1 d2 1 d3 1 O Label d1 2 d2 2 d3 2 O Label di nd d2 nd d3 nd O Label s1 1 s2 1 O O Label s1 2 s2 2 O O Label si ns s2 ns 0 O Label nnp 1 pi 1 p2 1 p3 1 Label nnp 2 pi 2 p2 2 p3 2 Label nnp np pi np p2 np p3 np Label ti 1 t2 1 t3 1 t4 1 Label t1 Q2 t2 2 t3 2 t4 2 Label t1i nt t2 nt t3 nt t4 nt Label The meaning of the above is nk Number of nodes nd Number of triangles ns Number of segments np Number of polygonal plates nt Number of tetrahedral volume elements defaults to 0 if not specified x t x coordinates of node in m is scaled by the SF card y t y coordinates of node i in m is scaled by the SF card z i z coordinates of node in m is scaled by the SF card di j Number index of the first vertex of triangle j d2 j Number index of the second vertex of triangle j d3 j Number index of the third vertex of triangle j sl k Number index of the starting p
159. ample S S Figure 8 1 Sketch illustrating the use of the BL card Parameters S The name of the begin point of the line S The name of the end point of the line R Normally the wire radius is set with the IP card Setting R overrides this radius for the current wire without affecting the default for later segments Ry is in m and is affected by the SF card scaling factor R By setting the parameter R it is possible to create a wire with a tapered radius The parameter R must also be set R then specifies the radius at point S while Ra specifies the radius at So EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 5 Examples of BL card usage The following commands create the segmented wire shown in figure 8 2 kk IP DP A DP BL A B EG EN w O ooo N oo oo e O O O Or Figure 8 2 Example of a BL card These commands create the tapered wire shown in figure 8 3 Ok IP DP DP rad BL EG EN SS Figure 8 3 Example of a BL card with a tapered radius 0 005 B rad 5 rad gt 1 wo LS PR o December 2002 FEKO User s Manual 8 6 DESCRIPTION OF THE GEOMETRY CARDS 8 2 3 BP Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S So S3 S4 Ry Ra IE REAL REAL REAL REAL REAL REAL REAL REAL With this card four points are connected to each other to create a parallelogram This parallelogram will then be subdivided into triang
160. an one direction of incidence is to be examined the right hand side of the linear equation system is changed but the matrix remains unchanged Thus it makes sense by using the CG card to use Gauss elimination default if a CG card is not used which performs a LU decomposition of the matrix When the direction of incidence is varied then only the relatively fast backward substitution has to be done EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 11 9 2 4 A1 Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 a ANFIULA EIR1 EIR2 EIR3 EIR4 EIR5 EIR6 IE REAL REAL REAL REAL REAL REAL REAL REAL With this card a voltage source is placed on a segment Parameters ANFL 0 New excitation replaces all previous excitations 1 Additional excitation add to previous excitations ULA Label of the segment to which the source is applied If more than one segment has the same label then source is applied to the last segment with label ULA Alternatively one may set ULA 1 then the feed segment is determined by specifying its Cartesian coordinates EIR3 y EIR4 and z EIR5 EIR1 Value of the voltage Uo in V EIR2 Phase of the voltage Up in degrees EIR3 Only if ULA 1 the x coordinate of the feed position in m EIR4 Only if ULA 1 the y coordinate of the feed position in m EIR5 Only if ULA 1 the z coordinate of the feed position in m The values EIR3 EIR4 and EIR5 are scaled by the SF car
161. an optimise for more than one frequency by using the frequency blocks from the output file from FEKO in the aim function The parameters M Ng and Ns are all specified on the line that follows the key word RUNDSTRAHLUNG or OMNIDIRECTIVITY M is a flag that has the following meaning 1 Ey components used M Y P 2 E components used Np is the number of the far field data blocks that are to be read and Ng indicates the number of rows that are to be read from each block i e the number of discrete points j pj when varying the angle For each block i 1 Np the roughness in dB is determined according to the relation Dee fi 20 log z minj E9 8 p3 Here j scans through the values 1 Ns The aim function Z is derived from I a Z is nee i e it is an average roughness in dB Apart from the value of the aim function Z the standard deviation of f withi 1 Np the block number i of the block with the worst value of the aim function and the current value of the aim function are written to the log file EM Software amp Systems S A Pty Ltd December 2002 THE OPTIMISER OPTFEKO 10 7 Example OMNIDIRECTIVITY 2 10 90 Radiation pattern This aim function can be used to optimise the radiation pattern according to an arbitrary shape specified by the user As for the isotropic radiator one can optimise for more than one frequency by using the frequency blocks from the output file from FEKO in the aim function
162. ance latency and bandwidth This is very useful when configuring parallel clusters The options can be added in a binary fashion for exam ple setting FEKO_MPISTATISTICS 5 will print both the run times and network performance EM Software amp Systems S A Pty Ltd December 2002 GENERAL COMMENTS 2 17 FEKO_SYSINFO If this parameter is set FEKO provides information about the computer system mostly used on UNIX platforms FEKO_TMPDIR This variable specifies the directory where FEKO will write paging files when using the out of core solution In the past it was required that the definition ended in a backslash Windows or a slash UNIX This is no longer required For example in UNIX it may be set with set FEKO_TMPDIR tmp export FEKO_TMPDIR FEKO_USER_HOME This directory is used to write user specific initialisation files This variable replaced FEKO_WRITE It is provided to allow different users to save unique configurations or for when the user does not have write access to the FEKO di rectory For Windows systems this is normally the same as FEKO and on UNIX systems it is usually HOME feko FEKO_WHICH MPI FEKO uses different MPI implementations for the different platforms and thus the different platforms require different command syntax to start FEKO RUNFEKO provides an interface that remains the same on all platforms However it must know which MPI implementation is used This is done by setting the environment varia
163. ancel button to disregard all changes EM Software 4 Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 33 3 5 8 2 Toolbars Unselect or select the Main item to hide or display the Main toolbar Unselect or select the Display item to hide or display the Display toolbar Unselect or select the Render item to hide or display the Render toolbar panel 3 5 8 3 Command line parameters This menu is used to specify optional command line parameters to PREFEKO and FEKO This is mostly useful for debugging purposes Note that these parameters are saved in the winfeko ini file and one should remove them once they are no longer required 3 5 9 Help menu 3 5 9 1 User s manual Select the Users Manual item under Help to start Acrobat Reader and automatically load the general FEKO User s Manual available in PDF format If nothing happens when this item is selected then a PDF viewer has probably not been installed on your system Acrobat Reader is available for installation on the FEKO CD 3 5 9 2 About WinFEKO Select this item to get the latest WinFEKO version number and development information December 2002 FEKO User s Manual THE EDITOR EDITFEKO 4 1 4 The editor EditFEKO A PREFEKO input file is a standard ASCII text file that may be created with any available text editor The model geometry and desired calculation are entered through lines of text referred to as cards Each card may have a number of parameters which
164. and A6 cards such that the complete card can only be displayed with Source number set to A11 Display types is used to turn off the display for certain excitation types If only one source is selected the amplitude and phase of the source is displayed when the Apply button is clicked As always if the box next to Excitation at the top is checked changes are processed immediately 3 5 7 Tools menu Some tools are available in WinFEKO to assist with model display and trouble shooting when the FEKO solver gives warnings or errors 3 5 7 1 Find Element The Find elements panel is activated when this item is selected The commands in this panel operate similar on both NEU and FEK models Note See comments on the Apply OK and Cancel buttons in section 3 5 5 7 The range of elements is presented under Valid range This can be quite useful with NEU files neutral file models where numbering does not necessarily start at 1 Type in an element number or list of element numbers to find As an example type 1 2 5 7 10 to search for element numbers 1 2 5 7 8 9 and 10 Under Options select one or more of the following e Display elements Enable or disable the display of the selected elements This option will thus override all the other options available e White colour If selected the elements in the Find list will be highlighted e Lead line Add a lead line between the selected element and the selected element number
165. and edited similar to loading and editing standard graph files The Load template menu merely simplifies selecting the template for a specific type of graph The modified template can be saved such that future graphs of this type will be created from this template See also section 5 3 1 7 5 3 1 7 Save template When creating a new plot GraphFEKO first determines if there is a template for this type of graph The template contains information such as the caption fonts the axis limits the line colour and type etc In principle the new plot will be similar to the template but using the current data Any graph can be saved as a template including a graph that has just been created This is mostly useful when one wants to create a series of similar graphs The templates have very specific names which depend on the parameter under consid eration and the type of data linear log dB The extension depends on the graph axis lin for line graphs or pol for polar graphs All the different field quantities on one parameter windows use the same template For example both the axial ratio and the electric field on the Far field panel use FFPar lin when plotting a line graph with linear data If the new plot has more lines than the template the template lines are used repeatedly Thus if the template has only one line all lines on the new graph will be the same w r t colour line type markers etc Note that plotting graphs from the Current ex
166. anes the top layer 0 extends to z 00 the last layer Iz ex tends to z 00 12 Layered dielectric media with two metallic ground planes the top one is located between layers 0 and 1 and the bot tom one at the bottom of layer Jz Metallic structures or field computations are only supported between the ground planes not above the top one or below the bottom one they are assumed to be infinitely large The material pa rameters of layer 0 are irrelevant 13 Layered dielectric media with a metallic ground plane at the top between layers 0 and 1 The last layer Ig extends to z oo Metallic structures or field computations are only supported below the ground plane December 2002 FEKO User s Manual 9 72 DESCRIPTION OF THE CONTROL CARDS Iz Number of layers in the substrate in the example in figure 9 25 there are 4 layers Medium 0 or the half space z gt Rg is not included in the number Ra Relative permittivity of medium 0 the half space z gt Re R3 Relative permeability ur of medium 0 the half space z gt Re Ra Conductivity o in T of medium 0 the half space z gt Re see the comment below Rs Electric loss factor tand in medium 0 the half space z gt Re see the comment below Re z coordinate of the upper boundary of layer 1 the uppermost layer see figure 9 25 in m note that it is scaled by the SF card Rz Magnetic loss factor tan 6 in medium 0 the half space z gt Re the complex perm
167. angle R Normally the triangle is segmented according to the triangle edge length specified with the IP card This is the default if the param eter R is not specified However it is often desirable to have an inhomogeneous segmentation for example in the transition from a finely segmented region to a region with coarser segmentation If set the parameter R specifies the triangle edge length along the edge S2 53 i e the side opposite S1 R is in m and is affected by the SF card scaling factor R Similarly to R but applies to the edge S3 S1 opposite S2 R3 Similarly to R but applies to the edge S S2 opposite S3 The three points need to be defined previously with DP cards The direction of the normal vector of the subdivided triangles is determined by the right hand rule through all the corners This direction only has meaning when used with the Physical Optics PO card or with dielectrics ME card December 2002 FEKO User s Manual 8 12 DESCRIPTION OF THE GEOMETRY CARDS Examples of BT card usage Through the use of the following commands the triangle in figure 8 10 will be created ko IP DP DP DP BT EG EN Ore oO 0 O GO O 00 0 O OGR e O O w oo gt e awe Figure 8 10 Example of a BT card The triangle with inhomogeneous segmentation in figure 8 11 is created with non uniform segmentation of a triangle DP A 0 0 0 DP B 5 0 0 DP C 2 3 0 1 0 3 IP 1 BT A B C 3 1
168. angles with label 2 are visible to some triangles with label 0 but not all Mo Y Figure 8 58 Structure used to demonstrate the use of VS cards We have to specify which triangles are visible hidden from all triangles with label 0 first then those visible from label 1 and so on The VS cards for this example would be as follows VS VS VS VS VS VS VS VS VS VS WUNDNNDNRRPRPOOO ewew preu PBR O PWWNWNPFP QRO NS Since all the triangles with label 0 lie in the same plane they cannot illuminate each other Thus the first card states that label 0 is hidden from label 0 EM Software 4 Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 105 All triangles with label 1 are visible from all triangles with label 0 This is specified by the second VS card Since some triangles with label 2 are visible from some triangles with label 0 while others are hidden we cannot specify any information for this combination of layers However the plate with label 2 shadows all triangles with labels 3 and 4 and we may specify that these are hidden This is done with the third VS card Note that this card specifies a range of hidden labels Next we must specify which triangles are visible or hidden from all triangles with label 1 As for label 0 triangles with label 1 are not visible to each other specified by the fourth VS card All triangles with labels 0 and 2 are visible from all triangles with label 1 Si
169. aphFEKO window The graph is saved to the file name associated with and displayed at the top of the active window 5 3 1 3 Save as The graph on the active GraphFEKO window can be saved to a different filename A standard Save as dialog is activated Select a new filename with extension wfg if any other extension is specified it will be changed to wfg as GraphFEKO can only open files with this extension EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM GRAPHFEKO 5 3 5 3 1 4 Close This item closes the active GraphFEKO window If the graph on the active GraphFEKO window has not yet been saved since the last changes or edits the user is warned before the window is closed 5 3 1 5 Clear template GraphFEKO allows the user to save graphs as templates to use when new graphs of similar type are created These templates have very specific names which depend on the options used to create the type of graph The Clear template menu allows the user to clear the template for a specific type of graph and revert to using the GraphFEKO defaults It opens a separate window where the user can select the various options which determine the template name As the user changes the options the template name is shown in the box at the bottom of the form See also section 5 3 1 7 5 3 1 6 Load template The templates which GraphFEKO uses when creating new plots are standard graph files with specific names These files can be loaded
170. ariables t1234x t1234y and t1234z give the coordinates of the point with index 1234 Note that points are not included by default Since points do not have an associated property ID points are imported irrespective of their label EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 47 8 2 17 IP Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 IP Ri Ra R3 Ra R5 IE REAL REAL REAL REAL REAL REAL REAL REAL With this card a number of parameters that define the density of the mesh are set Parameters R Segment radius in m it is scaled by the SF card R Maximum edge length of triangular elements in m it is scaled by the SF card R3 Maximum segment length for wire segments in m it is scaled by the SF card R4 Maximum edge length of dielectric cuboids in m it is scaled by the SF card Rs Maximum edge length of tetrahedral volume elements used with FEM in m It is scaled by the SF card The IP card only affects the commands following it i e it has to be declared prior to the cards that define segments triangles cuboids or tetrahedra It is possible to use more than one IP card in a file This is necessary when a finer mesh is required in certain parts or when different radii occur in the geometry For any command e g the BL card the previous IP card is applicable For the meshing process the following rules must be adhered to e The segment length must be
171. arisation 5 21845E 04 Watt left hand circular pol 7 13564E 04 Watt right hand circular pol 3 27386E 04 Watt 34 89 65 11 49 87 50 13 68 55 31 45 INN OA OA OA OS min h h h h h h Figure 14 1 Elliptic polarisation in the far field EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE OUTPUT FILE OF FEKO 14 15 where the first line of total power is calculated assuming that each specified point lies at the centre of an incremental integration area The effective area is therefore slightly larger than the area defined by the start and end angles The second line gives the power integrated over an area defined by the start and end angles For example one may request an integration from y 0 to y 350 and Y 5 to Y 175 both in 10 increments in which case the first total will give the total power through the sphere One may also request the integration from y 0 to y 360 and Y 0 to Y 180 in which case the second total will give the correct total power through the sphere The polarisation dependent power on the second block is calculated according to the effective area of the second line The definitions of S and Z polarisation can be found in the discussion of the far field plotting in section 5 3 2 8 14 7 S parameters If S parameters have been requested with an SP card FEKO prints different tables to the output file The first lists the impedance at each port al
172. around the z axis similar to Re Filename The name of the ffe or ASCII input file for I2 1 or Iz 2 The filename must be enclosed in double quotation marks and entered at or after column 111 The radiation pattern of the antenna must be specified in spherical coordinates V p with the phase centre thereof located at the origin of the local as used in the pattern data coordinates If this is not the case the phase of the far fields will not be correct For example if a ffe file is exported with FEKO for use with the AR card the origin should be shifted with the OF card to the phase centre of the antenna The vertical and horizontal components of the complex electric field EEF and or EP F must be specified at discrete angles 9 p5 with i 1 14 and j 1 15 These fields have the unit Volt the actual far fields are calculated from e JBR R e jBR R Es EY or E E5 with R the distance to the field point and 8 the complex propagation constant in the free space medium see the EG and GF cards These formulas are used for all distances R i e also in the near field However FEKO tests whether the far field conditions are met by calculating the directivity and equivalent aperture and gives an appropriate warning if this is not the case The permissible range of the angles J is 0 180 and they must be in ascending order Le 941 gt Vi However the angles do not have to be equidistantly spaced
173. ases the actual graph area This is useful when printing to high resolution printers 5 3 1 11 Print to file Select the Print to file option to print the graph on the active window to file Currently Windows bitmap bmp jpeg jpg gif gif Windows meta file wmf en hanced Windows meta file emf and postscript files are supported When printing to a bitmap format the file will have the same size in pixels as the current graph on screen For the postscript printing a postscript printer must be installed on your system The Adobe PostScript printer which can be down loaded from the Adobe web site is a good option Note that this printer can be set to print encapsulated PostScript but the files will still have the ps extension For each GraphFEKO session you will need to select this printer when you print the first PostScript file 5 3 1 12 Exit Select the Exit option to exit GraphFEKO All graphs will be closed and a warning will be given if the changes or edits made to any of the graphs have not yet been saved You also have the option to quite without saving any unsaved graphs if you answer No to this question you will be prompted for each unsaved graph 5 3 2 Import menu Used to load FEKO output data into GraphFEKO 5 3 2 1 Select file Use this option to select a FEKO output file out This is done automatically when GraphFEKO is executed from within WinFEKO or if GraphFEKO is executed with a
174. ated exported from FEMAP and the neutral file name is the same as the current project name e g dipole neu then the meshed ge ometry in this neutral file is loaded and displayed At the bottom of the display window an identification legend NEU File is drawn At present WinFEKO only displays line and triangle elements present in the neutral file 3 5 2 3 Run EditFEKO Select the Run EditFEKO item to start the program EditFEKO EditFEKO is started with the pre file associated with the current project e g dipole pre If no such file exists EditFEKO will still be started but with an empty file The FEKO environment variables must be set correctly for EditFEKO to start successfully from the WinFEKO environment This should have been done automatically by the FEKO installation program See the Getting Started manual EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 11 3 5 2 4 Run PREFEKO Select the Run PREFEKO item to run PREFEKO on the pre file associated with the current project similar to typing prefeko exe dipole pre at a command prompt The program PREFEKO is executed in a minimised command prompt PREFEKO program feedback is passed to a 1g1 file e g dipole lg1 which is displayed in the PREFEKO log file window opened when the Run PREFEKO item was selected Click on the Close button top right of PREFEKO log file window to close this window The FEKO environment variable must be set co
175. away from the respective edges When two apertures have a common side dipoles should not lie on the edges of both apertures otherwise two dipoles may have the same location and polarisation If this is the case the power calculation in FEKO will fail S1 The name ofa node point that defines the origin of the aperture Sa S3 For a planar aperture S2 and S3 specify the names of two nodes that define the corners of the aperture in the s and z directions respectively see figure 9 10 For cylindrical and spherical apertures they specify the directions of the local z and x axes respectively see figures 9 12 and 9 13 NSTART The number of the first field point to be used for the aperture For NSTART 1 field values are read from the start of the file for larger values the first NSTART 1 values efe and hfe files or lines text files are ignored This may be used for example if the data file contains the field values for more than one aperture NSTART is not used if the field data is obtained from the pre input file N2 The number of field points in the 51 52 planar aperture cylindrical aperture or Y spherical aperture direction N3 The number of field points in the S S3 planar aperture 2 cylindrical aperture or spherical aperture direction AMP A constant by which the amplitudes of all the dipoles in the aperture are scaled PHASE A constant phase added to all dipoles in the aperture Filename The input file
176. ax T T min i a i The reason for doing this is to avoid that one impedance value such as one port or the impedance at one frequency which has already an acceptable match is being optimised further and further instead of focusing on the optimisation of other impedance values where the desired match has not yet been obtained Apart from the value of the aim function Z the real part and the imaginary part of the input impedance Z are written to the log file the latter only for N 1 Maximisation or minimisation of near fields This aim function enables one to maximise the electric or magnetic field strength in the near field This is particularly useful for a transmitting antenna that radiates constant power In addition any linear combination with arbitrary proportionality factors of the electrical and magnetic fields can be maximised or minimised by using negative values of the proportionality factors If only the electric or magnetic field must be maximised the line following the keyword NAHFELD or NEARFIELD contains the parameters M Ng and Ng M is a flag and has the following meaning depending on the coordinate system used with the near field EM Software 4 Systems S A Pty Ltd December 2002 THE OPTIMISER OPTFEKO 10 11 calculation in the selected block or blocks se the S S components E se the Ey Ey components Ep components Z3 p M r Hr components E se the U U Use
177. bel Alternatively the label parameter ULA can be set to 1 then the position of the feed is specified in Cartesian coordinates This should simplify the modelling in most cases especially with the A7 card FEKO then search for a segment or an element at this position with the A7 card the specified point must be in the middle of the edge This comparison of the position uses the tolerance parameter EPSENT EG card section 8 2 12 The excitations are described in detail in the following sections December 2002 FEKO User s Manual 9 8 DESCRIPTION OF THE CONTROL CARDS 9 2 3 AO Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 NF THENPHI EIR1 EIR2 EIR3 EIR4 EIR5 DTHEI DPHII EIR8 IE REAL REAL REAL REAL REAL REAL REAL REAL This card realises excitation by a linearly polarised incident plane wave Parameters ANFL 0 New excitation replaces all previous excitations 1 Additional excitation add to previous excitations NTHEI If more than one direction of incidence is to be examined then this parameter indicates the number of incident directions points in the Y direction If this field is left empty or a 0 is entered then NTHEI 1 is set NPHII If more than one direction of incidence is to be examined then this parameter indicates the number of incident directions in the y direction If this field is left empty or a 0 is entered then NPHII 1 is set EIR1 Value of the field strength E of the incident field in Y EIR2 Phase o
178. ble FEKO_WHICH_MPI it is automatically set by the installation script to one of the following options Not initialised mpich for example Linux SUN IBM HP MPI NEC MPI on NEC SX 5 SGLMPI CRAY SGI MPI on CRAY T3E ScaMPI on Linux ix86 and Alpha Compaq MPI on Tru64 UNIX SCore on Linux Myrinet clusters GM on Linux Myrinet clusters AaNIa Fwnr oO o FEKO_WRITE This variable is obsolete and is replaced by FEKO_USER_HOME which has the same functionality on both Windows and UNIX systems December 2002 FEKO User s Manual 2 18 GENERAL COMMENTS FEKO_WRITE_RHS Tf this environment variable is set value arbitrary FEKO writes the right side of the set of linear equations to a rhs file This is only useful for test purposes such as when one wants to analyse this vector with another program FEKOLANG Selects the language of operation This must be either d for German or e for English FEMAP The directory where the CAD mesher FEMAP is installed OMP_NUM_THREADS This is set to 1 and is required by the libraries unsed in the FEKO kernel 2 8 Checking the validity of the results If a calculation has been done with FEKO the results have to be checked There are a number of ways of doing this e a comparison with exact results if these are available e a comparison with results that have been published in the literature e a comparison with another program that is based on another method of calculation e a comparis
179. by E F Eo ju Eo x o i The incident magnetic field is given by gt e Des Hl 7 PRA with Zp the wave impedance in the surrounding free space medium It should be noted that the incident power density which is required for example for RCS computations is given by 3 _ 1 Fol 2 Si 2 Ze 1 Uv R It is possible to vary the direction of incidence This is particularly useful when e g determining the monostatic radar cross section The two parameters EIR3 and EIR4 indicate the direction of the first wave The direction of incidence is varied in the Y direction by the increment DTHEI and in the direction by DPHII In each direction the NTHEI and NPHII angles are examined in total NTHEI NPHII incident waves are examined December 2002 FEKO User s Manual 9 10 DESCRIPTION OF THE CONTROL CARDS If an AO card with NTHEI NPHII gt 1 is read then all the following control cards until the next Ax FR or EN cards will be read into a buffer All these cards are then processed in a loop over all the different angles of incidence If e g the monostatic radar cross section is to be calculated for Y 90 and 0 lt p lt 180 the following command is used AO O 1 181 1 0 0 0 90 0 0 0 0 0 0 0 0 1 FF 2 41 1 EN The FF card is read into the buffer and processed 181 times Through the use of the parameter FFREQ 2 in the FF card the far field is calculated in the direction of the incident wave If more th
180. ccurrence of LINE Next the x y and z components of the start point follow the group codes 10 20 and 30 and those of the end point follow the codes 11 21 and 31 Here the start and end points are x y z 0 0538 0 0 8 134 and 5 110 2 857 0 0 respectively If any of the coordinate group codes is not present such as in a 2D model the related coordinate is set to zero The block is terminated by the group code 0 The wire is segmented according to the maximum segment length specified by the IP card and the segments also have the radius specified by this card Meshed surfaces are imported from blocks denoted with the keyword POLYLINE This block contains the layer name following the group code 8 as before if there is no group code 8 before the first VERTEX the label specified with the last LA card will be used and a number of VERTEX structures There can be an arbitrary number of VERTEX structures but there should be at least four The POLYLINE structure is terminated by the keyword SEQEND 0 POLYLINE 8 LAYER_02 VERTEX VERTEX VERTEX 0 SEQEND EM Software 4 Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 41 There are two types of vertices The first type defines points is space 0 VERTEX 8 LAYER_02 10 7 919192 20 3 393939 30 0 0 next keyword where the x y and z components of the point follow the group codes 10 20 and 30 The layer information is ignored The seco
181. cription of the File Format The filename of the geo file has to be present in the first line then the commands see below followed by END at the end Comments may be placed between the commands The respective commands must be placed in the first column and have to be in capital letters The command parameters are integers For each line a maximum of ten argu ments are allowed Care needs to be taken to ensure that the arguments appear in the correct columns which are 11 15 first argument 16 20 second argument 21 25 third argument etc December 2002 FEKO User s Manual 12 2 THE PROGRAM LFFEKO 12 3 1 CUTEDGE command With this command the cuts can be added An inner edge is separated by the indicated two adjacent triangles After the command a pair of triangles is always expected which have a common inner edge The triangle with the second number is duplicated The indicated inner edge of the second triangle becomes a free edge The input method allows the transformation of a single basis function If the edge has more than one original basis function as is the case for connected plates a specific original basis function can be transformed If more than one edge is to be separated then the entries follow in the next line The input is completed with the command CUTEND Example Cuts are added between the triangles 2 and 3 as well as between 8 and 19 CUTEDGE 2 3 8 19 CUTEND 12 3 2 DELLOOP command The argum
182. cs approximation In LFFEKO the maximum number of edges that can be connected to a node i e the maximum number of loop basis functions per edge The maximum number of nodes between segments The maximum number of layers for the special Green s function of a planar substrate December 2002 GENERAL COMMENTS 2 15 maxnlp The maximum number of loops that may be formed in LFFEKO maxnqua The maximum number of dielectric cuboids maxnseg The maximum number of segments maxntetra The maximum number of tetrahedral volume elements for a FEM solution maxnzeile The maximum number of basis functions in the moment method area maxpoka The maximum number of bordering edges to the PO area maxpok1 The maximum number of wedges in the PO area maxpolyf The maximum number of polygonal surfaces that can be used to represent a body in the UTD region maxpolyp The maximum number of corner points allowed for a polygonal plate maxpovs The maximum number of label to label visibility specifications set by VS cards a card with a range sets a number of entries equal to the size of the range maxsklayer The maximum number of layers at an SK card maxtlcards The maximum number of TL cards maxutdzyl The maximum number of cylinders in the UTD region nmat The memory size that may be allocated for the matrix of the system of linear equations For nmat 0 the necessary amount will be al located dynamically The allocation is not
183. d Is Determines which ray contributions to take into account 1 Geometric optics GO i e direct and reflected rays and shadow regions are taken into account 2 Diffraction on edges and wedges as well as reflections and a diffraction are taken into account 4 Corner diffraction 8 Double diffraction on edges and wedges and combinations of re flections are taken into account 16 Creeping waves on curved surfaces 32 Tip diffraction at the tip of a cone A value of J5 7 1 2 4 means that e g the UTD is applied using reflections and a simple edge and wedge diffraction as well as a corner point diffraction are used In normal cases I together with Iz should be a compromise between accuracy and computational time December 2002 FEKO User s Manual 8 100 DESCRIPTION OF THE GEOMETRY CARDS R The variable Rj UTDNOCOUPL specifies whether the coupling from the UTD region to the MoM region should be considered 0 The usual option that is the coupling of the MoM region with the UTD region is considered 1 The coupling of the MoM region with the UTD region is neglected that is there is no coupling back to the MoM region from the UTD region shadowing reflection This option is especially relevant when the MoM region and the UTD region is not situated close together When no UT card is used the following default values apply fi 1 Lb 3 l3 0 fa 0 ls 7 Ri 0 The following restrictions apply for the hybrid MoM UTD e
184. d L4 cards Positions where the near field is calculated with the FE card Offset in the near field calculation OF card section 9 2 34 Note that if for example all data are specified in mm with SKAL 0 001 all input values are interpreted as mm This also applies to the segmentation parameters IP card and possible translations TG card December 2002 FEKO User s Manual 8 90 DESCRIPTION OF THE GEOMETRY CARDS 8 2 33 SU Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 IE REAL REAL REAL REAL REAL REAL REAL REAL With this command the program runs in the superuser mode so that special parameters may be set Parameters I The password to enter super user mode The super user mode is only available to the code developers as it ignores the sensible defaults warnings and errors given by FEKO Iz This variable sets BLOCKNB the block size for the solution of the matrix equation with ScaLAPACK both in main memory and using an auxiliary file Typically a sensible value is allocated when the SU card is not used so that this is only necessary when performance tuning is required for specific computational architecture Note that Iz can be set without setting I I3 Indicates the file system type for the parallel version of FEKO with the solution of the matrix equation when an auxiliary file is necessary out of core ScaLAPACK 0 Default 1 Distributed this means every process has its own file 2 Shared a single file f
185. d if SKALFLAG 1 EIR6 The port impedance if this excitation is used in connection with S parameter calculation If this field is empty or 0 the value specified at the SP card is used This value is only used if the S parameters are requested with an SP card The vector of the voltage lies in the direction from the beginning of the segment to its end in the direction in which the segment was created by the BL card This is the direction of the current flow through the segment The internal EMF electromagnetic force of the impressed voltage source is in the opposite direction December 2002 FEKO User s Manual 9 12 DESCRIPTION OF THE CONTROL CARDS 9 2 5 A2 Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 A ANFYULA EIR1 EIR2 EIR3 EIR4 EIR5 EIR6 A IE REAL REAL REAL REAL REAL REAL REAL REAL With this card a voltage source is placed at a node between two segments or between a segment and a triangle ground plane or polygonal plate Parameters ANFL 0 New excitation replaces all previous excitations 1 Additional excitation add to previous excitations ULA The label of the segment at which begin point the excitation is located The excitation has to be located at a node either between two segments or between a segment and a triangle ground plane or polygonal plate The label must not be am biguous i e only one segment with this label should be de clared If there is more than one segment with this label then only
186. dard Windows appli cations The New sub menu item opens a sub menu where the user may choose pre for PREFEKO opt for OPTFEKO or tim for TIMEFEKO files EditFEKO will enter the appropriate mode depending on the selected option The Save menu will ask for a filename if the file does not have one otherwise it will save without confirmation using the current filename The Save as UNIX menu can be used to convert to UNIX end of line characters Save all files saves all unsaved open files This is followed by a list of recently used files and the printing and exiting menu items Various hot keys are presented next to the respective menu items Note that lt Alt gt lt X gt will save the current file and quit If there are other unsaved files open the user will be given the option to save them December 2002 FEKO User s Manual 4 2 THE EDITOR EDITFEKO 4 1 2 Options menu This menu allows some customisation of EditFEKO Both the screen and printer fonts may be set it is recommended that a fixed width font such as Courier New be used The Options menu also allows the user to move the button panel to the left or right of the editor area or to switch it off completely allowing more space for the editor windows The Options menu may also be used to enter the superuser mode This will print a warning but is open to anybody using EditFEKO This mode activates certain options which are only available in the superuser mode of FEK
187. default is based on the near field grid spacing To return to the default value enter 0 in the Arrow length edit box and hit the Enter key Select the plane ay yz or xz of the ortho slice and the level in this plane 3D Level slider under Plane For near fields calculated on other coordinate systems e g cylindrical or spherical the plane selection options would change to rho phi phi z rho z and rho theta theta phi rho phi respectively Cartesian Cylindrical around z axis Spherical Cylindrical around x axis and Cylindrical around y axis are displayed correctly in WinFEKO Fields calculated on a Conical coordinate system or at specified points as is possible with the FE card in FEKO cannot be displayed in WinFEKO For this use GraphFEKO to extract the near field data The available Near field quantity and Component can also be selected if available The Pointing vector S is only available when both E and H fields have been calculated at the same positions with FE card SAR is only available if the near electric fields in dielectric regions have been calculated See section 3 5 5 9 for a discussion on what exactly is displayed when different near field quantities components etc are selected Select Linear or dB scaling under the Scaling options Min minimum and Maz max imum slide bars and edit boxes are available to clip the limits of the data Also under Scaling is the wt option By default
188. der the FEKO installation directory It is also avail able in this directory on the FEKO CD 10 3 4 Defining the aim function A number of different aim functions are available in OPTFEKO Gain With this aim function a maximisation of the gain directivity of an antenna in one or more directions can be done The optimisation can be done over a broad band by examining a number of frequencies In such a case the average gain is maximised This aim function is selected by using the keyword GEWINN or GAIN in the opt file In the next row two additional parameters M and N are specified M is a flag with the following meaning 0 both polarisations M 1 horizontal polarisation 2 vertical polarisation December 2002 FEKO User s Manual 10 6 THE OPTIMISER OPTFEKO N indicates the number of blocks in the output file from FEKO that are to be read For each block i 1 N the first row is read and the gain directivity gi in dB is extracted The aim function Z is then defined by 1 Y Zaye 20 The negative sign ensures that a minimisation of the aim function maximises the gain Apart from the value of the aim function Z the standard deviation of the g with i 1 N the block number i of the block with the worst value of the aim function and the value of this aim function are given Example GAIN 0 1 Isotropic radiators This aim function allows the user to design an antenna with the best possible isotropic gain Here one c
189. diated power required to calculate for example the far field gain directivity can only be calculated ac curately if the mutual coupling between segments is taken into account Due to neglecting the point charges at the ends of the segments the coupling cannot be determined accurately If exact values of the radiated power are required it should be determined by integrating the far field see the FF card It should be noted that for example the computed near and far fields the actual field strength values the induced currents coupling factors losses are computed correctly EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 27 9 2 14 AP Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 NSTART Filename Filename INT INT INT INT INT STR STR STR STR STR With this card a planar cylindrical or spherical aperture of measured or calculated field values is converted into an equivalent array of electric and magnetic dipoles The card is processed by PREFEKO and replaced by the required number of A5 and A6 cards in the fek file Parameters ANFL 0 New excitation replaces all previous excitations 1 Additional excitation add to previous excitations TYPE 1 Read electric field values for a planar aperture from a file in efe format u H N Read magnetic field values for a planar aperture from a file in hfe format Read electric field values for a p
190. dition requires that skin gt o where 0 is the wire radius pi t 1 d1 The surface impedance is given by Z are For metallic surfaces the condition skin gt L must be met The surface 2 impedance is given by Zs a e 3 exact expression of the skin effect The required parameters are y tan and g and for surfaces also the thickness d A good conductivity is required i e o gt wey For wires with radius o the surface impedance is given by g i Jol 3 ee 27006skin Jy 1 j are where Jo and J are Bessel functions For metallic surfaces the surface impedance is given by 2 cae 1 200skin tan a a j z December 2002 FEKO User s Manual 9 92 DESCRIPTION OF THE CONTROL CARDS Examples are given in example_02 and example_33 in the Examples Guide I 4 thin isotropic dielectric layers This option only makes sense for triangular surfaces not for wires The required parameters are d Hr tan and e as well as or tan Under special circumstances it is possible to specify both and tan for example to approximate a specific frequency response FEKO will give a warning which may be ignored The triangles with the label J exist in a certain environment e He which is usually specified with the EG card It is also possible to place the triangles within a dielectric body in this case the environment is specified by the parameters of the DI card The u
191. dsgd ee niadusb an OS OU CA ng 66 is ee ee he Oo eb sea EGS S x oe 2 8 oe eee Bo 5 6 oR DSS ERE S EEEE E eG Ga Gees CO OM E E babe ee ben beeeese 250 TO Card ccccscesa nae eek Boao me PRPS Sras 8236 TOC i hd oo ee ee en A A 2265564 b ave ehh 644K oS REE ES ERES UT Oad cbc s cdr hedewe bbb ced ohid Sees o ee bd hk WS oe PERLE SSS WOM VO Card oc hh oS G4 db bed bend eae ea POA We Cae eo oo os ORE bode oR EE aS dens ETO be baw dd eens ghee kcpidnenex 9 Description of the control cards 91 9 2 December 2002 Overview of control cards and remarks on execution sequence OL WOM 1 i tk eG Bess SS Ewe bee E EOS aed OO WM e ereraa A A ew E E Dan AMA io oe oe ea eB AI O24 AT oop pe e228 4464 ee OE LE RARA 925 AQCerd coec cece ee ee ee eb ebb ee ea een nes O20 AS Caml ooo a a AAA eae U2 FAW o ee eG hk eee ee PHOS SHE PLA HON AAA ee O20 AO Cad oe oon ee hE e a RRA FEKO User s Manual vi CONTENTS 9210 AY Card oc ee ee ee ae e RR 9 19 A eee ee eee eee ee HH eR CRD we we 9 20 Oe Fe EE 9 23 9 213 AL Card oo 662d eee aaa DR eee aes 9 25 Sada ALA oo dia ph bi eee ea aal al de 9 27 ONS AR IIA 9 34 9216 AV Cad 2c ee cae aaa ede ee eee baa ae hes 9 39 ONY IO CANN oo py Rae a g a SO ap aS See 9 41 We COM AN 9 43 9219 A eae ea Re eR A eS 9 46 Dew RAP oag ouei ded eee a wea od debe de 9 47 O22 e hi ee es we EOS Ee RRR 9 50 tee LAE vad ee ea a ee ee a hs 9 52 De og EN Gud koe ye ee aeaa 4 Re we ee ee a we aed 9 53 A PE CAW soe ee
192. e at present e All files All the files in the current project directory e g dipole will be copied to the new directory e g dip_2 Also all files in the current project directory with the name dipole will be renamed as dip_2 in the new directory e g dipole pre dipole fek etc are renamed as dip_2 pre dip_2 fek etc e Model files Only the model files in the current project directory e g dipole pre dipole mod dipole neu dipole fek will be copied to the new directory and renamed e Pre files only Only the pre file in the current project directory e g dipole pre will be copied to the new directory and renamed Click the OK button This will start the copying and renaming The current project is closed and the new project is loaded 3 5 1 6 Printing Select Print to print the model display On selection the Winfeko Printing window is activated Select printing to Printer File or Clipboard A standard windows printer setup may be activated by selecting Printer setup A Quality option can be selected Presentation quality results in a better quality print especially when printing to a colour printer but more memory approximately 16 times more than Fast is required It also takes longer to print Presentation quality Normal quality is a good compromise requiring four times more memory than Fast and being faster than Presentation quality The paper size Default or A4 can be selected On printing to a pri
193. e field strength such as directivity and gain is not required but the total radiated power has to calculated from the integral of the Poynting vector see the discussion below If a ffe file has been requested with the DA card it is written as if for FFREQ 1 Unless it is turned off by a later DA card Positive values of FFREQ The total field is calculated This includes all source contributions except plane wave excitations Negative values of FFREQ The field radiated by the impressed sources such as Hertzian dipoles are not included This op tion is only meaningful if only the scattered field is required Normally one would use positive values of FFREQ NTHETA The number of observation points in the Y direction An empty field i e NTHETA 0 will be set to NTHETA 1 NPHI The number of observation points in the y direction An empty field i e NPHI 0 will be set to NPHI 1 RIGE 0 The directivity of an antenna is calculated 1 The gain of an antenna is calculated THETAO 9 coordinate Jo in degrees of the first observation point PHIO y coordinate yo in degrees of the first observation point DTHETA Increment Ay in degrees of the angle 9 DPHI Increment Ag in degrees of the angle y December 2002 FEKO User s Manual 9 64 DESCRIPTION OF THE CONTROL CARDS When calculating the monostatic radar cross section for a number of directions of inci dence the parameter FFREQ 2 is necessary otherwise FFREQ 1 can be used
194. e see section 5 3 1 11 Main graph edit no associated menu item This speed button is used to return to the Main graph settings panel NO om FW DY December 2002 FEKO User s Manual 5 2 THE PROGRAM GRAPHFEKO 5 2 2 Data extraction toolbar 2 m 0 8 9 u e e e 2 3 4 5 6 7 8 9 10 Used for extracting data from the FEKO output file The functions of the buttons are 1 Import select a FEKO out file see section 5 3 2 1 2 Extract antenna parameters see section 5 3 2 3 3 Extract S parameters calculated with the SP card see section 5 3 2 4 4 Extract network parameters using antenna source see section 5 3 2 5 5 Extract receiving antenna data see section 5 3 2 6 6 Extract currents see section 5 3 2 7 7 Extract far field data see section 5 3 2 8 8 Extract near field data see section 5 3 2 9 9 Extract results for an adaptive frequency interpolation see section 5 3 2 10 10 Reload out file no associated menu item This button reloads the current out file from disk and opens the last parameter panel It is very useful when one repeatedly changes parameters reruns FEKO and plots the data 5 3 Main menu structure 5 3 1 File menu 5 3 1 1 Open Select this item to open an existing graph created with GraphFEKO A standard windows Open file dialog is activated Only files with the extension wfg can be opened 5 3 1 2 Save Select this item to save the graph on the active Gr
195. e the size of the triangles in the direction orthogonal to the wire should be similar to the distance from the wire to the plate in order to give an accurate representation of the surface charge distribution If the segmentation rules are not adhered to then the following errors and warnings will be reported Firing Ratio of the segment length to the wavelength Ratio of the segment radius to the segment length Ratio of the area of the triangles to the wavelength squared Ratio of the cuboid edge length to the wavelength Ratio of the cuboid edge length to the skin depth EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 49 8 2 18 KA Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 mo NT R NT NT REAL REAL REAL REAL REAL REAL REAL REAL With this card two points are joined which form the border of the PO area On this edge fringe wave currents are taken into account Parameters S Name of the begin point of the edge S2 Name of the end point of the edge S3 Label of the PO triangles adjacent to the PO border i e the edge is assigned to all triangles with the same label The direction of an edge is arbitrary i e it does not matter which edge point is chosen as the end or start point of the edge December 2002 FEKO User s Manual 8 50 DESCRIPTION OF THE GEOMETRY CARDS 8 2 19 KK Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ry Ra R3 Ra R5
196. e to hide substrate 2 and display substrates 1 and 3 type 1 3 in the edit box Select the Back button to return to the main FEK file display options panel EM Software 4 Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 27 3 5 6 4 Geometry NEU display options On selection of this item the Neutral file display options panel is activated Layers associated with the NEU file are presented in the Available layers list if a neutral file has been loaded for display see section 3 5 2 2 Note See the comments on the Apply OK and Cancel buttons in section 3 5 5 7 To display only selected layers copy the appropriate layers to the Selected Layers list use the arrow buttons Select the Selected layers option under Layer visibility to display entities associated with the selected layers Unselect any of the options under Element visibility to hide specific types of entities Select one of the options under Colours to determine how colours are used with the model display Select the Legend option in the Main display options panel for colour code identification The options are e Element type Use colour codes associated with line segments or metallic trian gles cuboids and polygons not implemented yet This item is the default colour selections e Layer number Display the different NEU file layers in different colours 3 5 6 5 Geometry Cutplane options The Cutplane options panel is activated when this item is s
197. e IP card can be overridden along the arc by setting Ra The radius of the arc is given by the distance between the points S and S3 Examples of CL card usage The following commands creates the wire arc shown in figure 8 13 IP DP DP DP CL EG EN gt e awe O O OO wooo Oroo O oo UY Figure 8 13 Example of a CL card December 2002 FEKO User s Manual 8 16 DESCRIPTION OF THE GEOMETRY CARDS The following commands creates the tapered wire arc shown in figure 8 14 IP DP DP DP CL EG EN 01 gt a we oooo oooo B C 270 Figure 8 14 Example of a CL card with tapered wire radius EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 17 8 2 8 CN Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 A IE REAL REAL REAL REAL REAL REAL REAL REAL This card is used to reverse the normal direction of previously created triangles and or polygons for example after importing CAD data The normal direction is important in some cases such as when defining dielectric surfaces Parameters I 0 Reverse the normal of all triangles with label Jo 1 Reverse the normal of all polygons with label Jo 2 Reverse the normal of the triangle with absolute number Io 3 Reverse the normal of the polygon with absolute number Io I gt The label or absolute element number depending on the value of J For triangles the normal vector is reversed by interchanging corners 1
198. e SF card if SKALFLAG 1 December 2002 FEKO User s Manual 9 26 DESCRIPTION OF THE CONTROL CARDS The following restrictions apply when using the impressed current elements e It is not possible to attach the impressed current to a wire segment in the FEKO model If the impressed current is making electrical contact with a triangular surface current element the AV card should be used e When modelling dielectric bodies with the surface equivalence method the current element must be in the free space medium i e outside the dielectric bodies The material parameters of this medium can however be set with the EG and or GF cards e When used with the spherical Green s function the current element must be outside the dielectric spheres e The current segments may be joined with each other and with the AV card to form long paths and or closed loops The point charges which arise when the current does not go to zero at an end point or when there is a current discontinuity at a connection point are not taken into consideration This is required to model for example the case where radiating lines are terminated in a non radiating structure If these charges must be considered explicitly the line current should be modelled by a row of Hertzian dipoles see the A5 card Note however that the constant line charge along the current segment is correctly taken into account e If several of these current elements are used the total ra
199. e Show numbers Display the numbers associated with the selected elements e Both sides Draw lead lines highlighting and numbers on both sides of the selected elements Not applicable to line segments Click the Entity Selection button to jump the the Entity Selection panel where the on screen entity selection or picking options can be set see section 3 5 7 4 December 2002 FEKO User s Manual 3 30 THE PROGRAM WINFEKO 3 5 7 2 Transformation The Transformation control panel is activated when this item is selected Note See comments on the Apply OK and Cancel buttons in section 3 5 5 7 Note further If the checkbox next to the Transformation control caption is checked then the panel is activated This means that any changes made to the options available on the panel will be applied immediately This is sometimes useful but with the panel activated rendering can become very slow Under Vantage points the require view angle can be set The Y and y angles describe the direction in spherical coordinates of the viewpoint relative to the origin Under Zoom the user may set the Zoom factor and the Zoom step which determines the rate by which the zoom factor increases or decreases when for example the Zoom in or Zoom out buttons are clicked Under Translation the required pan position of the model can be set The origin of rotation can be changed under the Origin options By default the model is rotated around t
200. e an inductive approximation of the feed pin and transform the impedance such that it is referenced to the ground plane EIR1 Absolute value of the excitation current Jo in A The positive current direction is the positive z direction EIR2 Phase of the current Jp in degrees EIR3 Only if ULA 1 the x coordinate of the feed position in m EIR4 Only if ULA 1 the y coordinate of the feed position in m EIR5 Only if ULA 1 the z coordinate of the feed position in m EIR6 Only if Ell3 1 the radius of the coaxial probe feed pin in m The values EIR3 EIR4 EIR5 and EIR6 are scaled by the SF card if SKALFLAG 1 EIR7 The port impedance if this excitation is used in connection with S parameter calculation If this field is empty or 0 the value spec ified at the SP card is used This value is only used if the S parameters are requested with an SP card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 15 The excitation is shown in figure 9 4 A typical application of the A4 card is given in example_30a pre Examples Guide It is of course possible to discretise the vertical pin into segments and feed one of the segments with a voltage source Al card The ad vantage of the A4 card is that there are no vertical currents which results in substantially simpler Green s functions and a significant reduction in computing time Source point Feed triangle Figure 9 4 Excitation
201. e connected with AI cards or further AV cards If there is a current discontinuity at this point the resulting point charge is not considered see the discussion given with the AI card Line charges along the current path and surface charges on the triangles are correctly taken into account At the connection point 7 a continuous current model is used such that a point charge is not possible here EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 41 9 2 17 BO Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 LA EPSRF SIGRF MUERF TAND TAND RF MUERF EPSRF INT INT INT A IE REAL REAL REAL REAL REAL REAL REAL REAL With this card a ground plane at z 0 can be specified for all computations following the BO card The reflection coefficient method is used Parameters FLAGRF 0 No ground plane or use one of the other ground plane op tions such as the GF card for an exact model of real ground or the SY card for a perfect ground plane This option is used to switch off the reflection ground if the effect of different grounds are considered in a single input file 1 Use the reflection coefficient ground plane approximation with the material parameters specified in the remaining in put fields 2 Use an ideal electric ground in the plane z 0 In this case the remaining parameters are ignored 3 Use an ideal magnetic ground in the plane z 0 Also in this case the remaining
202. e edge S4 S The points have to be predefined using DP cards prior to the BQ card and are connected in the order in which they appear in the BQ card In principal the BQ card can create all types of quadrangles including parallelograms The difference is that the BP card creates a regular subdivision The direction of the normal vector A of the subdivided triangles is determined by the right hand rule through all the corners This direction only has meaning when used with the Physical Optics PO card or with dielectrics ME card EM Software 4 Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 9 Example of BQ card usage The commands below will create the quadrangle in figure 8 7 IP DP DP DP DP BQ EG EN oro Oo O OOGO oO O 0 00 gt U0QuUu O OGOOGO Orero PR00O0O Figure 8 7 Example of a BQ card A plate with a finely segmented slot as shown in figure 8 8 can be created with the following sequence of commands Nonuniform meshing for a slot in an aperture all dimensions in mm SF 1 0 001 len 20 length of the aperture wid 2 width of the aperture pl_len 50 length of nonuniform mesh plate around slot pl_wid 30 width of nonuniform mesh plate around slot tot_len 120 total length of the plate tot_wid 60 total width of the plate fedge_ap 1 5 edge length around the aperture Hedge_glob 5 global edge length IP edge_gl
203. e frequency sampling If this flag is used only one AC card and no FR cards is permitted in the pre file Is Only used for I4 1 then it specifies the maximum number of discrete frequency points to be used during the adaptive analysis see also the parameter NFREQ at the FR card for FREQF 2 Ri Inthe case Iz 2 the parameter R specifies the radius of the impressed current elements This parameter is optional and is passed on to the AI and AV cards See the description of ETR6_2 in these cards If Ry is zero or empty a current filament approximation is used R Only used for J 1 then it specifies the minimum frequency stepping see also the parameter DFREQ at the FR card for FREQF 2 Filename The name of the rsd file to read The filename must be enclosed in quotation marks and start in column 81 or after that of the pre file The frequency is defined in the rsd file thus the preceding FR cards are ignored when processing an AC card All commands after the AC card in the FEKO input file for example FF FE OS GF BO are processed within a frequency loop through all the frequencies in the rsd file The loop is terminated by any of the following three cards these cards are not included in the loop they terminate e AC importing a new rsd file or using the flag Iz 0 e FR manually setting a new frequency e EN end of the FEKO input file For example if a CableMod file must be read and
204. e near field data is loaded from the current project output file and the Near field options panel in WinFEKO is activated The near field data is displayed in 3D together with the model geometry Right click on the near field ortho slice to display information associated with the fields at the point of selection Note See the comments on the Apply OK and Cancel buttons in section 3 5 5 7 Note further If the checkbox next to the Near field options caption is checked then the panel is activated This means that any changes made to the options available on the panel will be applied immediately This is useful if for example ortho slices at EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 19 various levels are to be displayed without hitting the Apply button each time the level is changed With the panel activated rendering can become very slow Select a frequency and near field block from the lists under Data block selection Select the Lines Surface Colour or Arrows options under Display options The Colour option is only available if the Surface option has been unselected With Lines selected contour lines are drawn With Surface selected a colour shaded picture of the ortho slices is displayed Unselect Surface and select Colour to display a colour coded contour plot With Arrows selected the Arrow length edit box is activated The maximum arrow length can be set here by the user The
205. e noted that the SP card adds load impedances to all the ports For Al A2 and A3 sources it uses LZ type loads for A4 sources it uses L4 type loads and for AE sources it uses LE type loads If any similar loads were applied to the source position before the SP card these loads will be overwritten Also when execution continues after processing the SP card these loads will still be present The original amplitudes of the excitations will however be restored December 2002 FEKO User s Manual 9 94 DESCRIPTION OF THE CONTROL CARDS 9 2 40 TL Card 20 25 30 40 50 60 70 80 90 100 I4 I5 Ry Ra R3 R4 R5 Re R7 f A 1 1 rA Ri RS RS R4 RE RG E REAL REAL REAL REAL REAL REAL REAL 110 Rg REAL This card is used to connect a non radiating transmission line between two segments Parameters h Ip Is La Ry EM Software amp Systems S A Pty Ltd 1 This TL card does not define a transmission line but all previously defined transmission lines are deleted All the other input parameters are ignored 0 Defines a new transmission line all previously defined trans mission lines are replaced 1 An additional transmission line is defined Label of the segment which represents the start of the trans mission line If more than one segment with this label exists then the last segment with this label is used In the special case Iz 1 the start point of the transmission line is de fined by specifying its Car
206. e total number of field points FELKOR must be set to 6 The FE card is followed by exactly ANZZ lines Each of these specify the a y z coordinates of one point in the first three real parameter fields A simple example with three points are as follows FE 1 3 6 1 24 0 2 0 7 3 87 0 25 0 8 2 5 0 2 1 2 If a ground plane is used a calculation of the near fields in the ground plane is not possible The observation points in the area z lt 0 are not taken into account It should be noted that the coordinates may have an offset OF card Thus the near field on the surface of a sphere can be calculated with the centre of the sphere not being located at the origin of the coordinate system EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 63 9 2 25 FF Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 FF NTH NPHIRIGE THETAO PHIO DTHETA DPHI REQ ETA IE REAL REAL REAL REAL REAL REAL REAL REAL This card controls the calculation of the far fields in spherical coordinates Parameters FFREQ 0 No calculation is done The far field is calculated using the following parameters w H rT A N e The far field is calculated only in the incident direction used for example to calculate monostatic RCS 3 The far field is calculated as for FFREQ 1 but it is not written to the output file in order to limit the size thereof This option is meaningful when the individual values of th
207. e two current lines interpreted as the real and imaginary components i e Amp y Re Im2 5 3 4 5 Re Im gt Phase This determines the phase in degress all four quadrants of the two current lines in terpreted as the real line with the lowest number and imaginary line with the highest number components i e Phase atan2 Im Re 5 3 4 6 Amp Phase deg gt Re This calculates the real part interpreting the two current lines as the magnitude line with the lowest number and phase in degrees line with the highest number i e Re Amp cos Phase 5 3 4 7 Amp Phase deg gt Im This calculates the imaginary part interpreting the two current lines as the magnitude line with the lowest number and phase in degrees line with the highest number i e Im Amp x sin Phase December 2002 FEKO User s Manual 5 20 THE PROGRAM GRAPHFEKO 5 3 4 8 Log _10 Abs Line A This takes the logarithm to the base 10 of a graph It can be useful to convert values to dB if they were not plotted as such The absolute value is taken before taking the log This item can be called with one or two lines visible on the graph the operation is performed on the visible line with the lowest number 5 3 4 9 Sqrt Abs Line A This allows taking the square root of a graph The absolute value is taken to avoid imaginary numbers This item can be called with one or two lines visible on the graph the operation is performed on the v
208. e value in one of the coordinate lists Plotting the near field data as a function of frequency Some near field quantities can be plotted as a function of frequency if more than one frequency solution is available EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM GRAPHFEKO 5 15 Select a range of frequencies click and drag with the mouse The Independent variable under Plot options will change to Freq range Now select the coordinate values of the point for which the field must be plotted Selecting the plot options The desired Near field quantity and the Component of this quantity determine what field quantity to plot The user may then select to plot the real and imaginary parts or the magnitude or the phase of the selected field quantity Note that not all options are available for all quantities and not all quantities can be plotted simultaneously The user can of course add the additional quantity to the same plot by selecting this quantity and clicking the Add to graph button For example if mag is selected under Components to give the total field at the specified position only the mag option is available on the line below The quantities which can be plotted are e E_field This is the electric near field as calculated by FEKO This option is only available if the appropriate near field calculations have been requested FE card e H_field This is the magnetic near field as calculated by FEKO This optio
209. eability is given by u Hokr 1 j tan This line is followed by a further 72 lines i e I2 1 lines in total to specify the parameters of all the layers The parameters are taken from top to bottom and are as follows R The thickness of the layer in m see also the parameter h in figure 9 25 note that it is scaled by the SF card When the parameter GFFLAG 11 or 13 the last bottom layer is in finitely thick The field R can then be set to any value R Relative permittivity e of the layer Rs Relative permeability ur of the layer Ra Conductivity o of the layer Rs Electric loss factor tand of the layer see the comment below Rz Magnetic loss factor tan 6 of the layer Losses in any layer or the half space z gt Rg may be specified through assignment of either the conductivity o parameter R4 or by the electric loss factor tan parameter Rs Only one of these input values may be used the other must remain empty They are related by tan cee It should be noted that inside a frequency loop with varying w the first option is constant while second one is not Metallic structures can have an arbitrary orientation horizontal vertical and also diagonal They can lie at an arbitrary position in one or more layers and can lie directly on the border of two layers e g on the surface of a substrate The only restriction is that no metallic segment or triangle may cross a boundary between layers i e it
210. ec tions in the Ray type group If for example Corner diffraction is unchecked such rays will not be displayed Note that Diffraction only refers to single diffraction if this is unchecked double diffracted rays will still be shown unless the Double diffraction field is also unchecked Rays with more than the specified number of reflections will not be shown EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 23 Each ray group includes all rays that start and end at the same point The Selection options can be used to display individual ray groups Check the Ray groups checked box to display only the ray group with the number selected from the drop down list If the Ray group box is unchecked all rays are displayed simultaneously this may require a very significant rendering time The Ray number field can be used to view the rays in the group one by one The Far field crop slide bar can be used to restrict far field points to within the geometry display The ray data is also considered when calculating the model extent used for model nor malisation It could thus be necessary to re normalise the geometrical model display after clearing the ray file information 3 5 5 14 Clear data This item clears all information associated with the output data of the current project All memory allocated when loading the output file data is released Unlike the Clear item under Preprocessing this command does not
211. ecifies the direction of the x axis as well as the radius of the cylinder The points are placed at the y values as specified with the field data For spherical apertures S S2 specifies the direction of the z axis and S S3 the x axis S2 and S3 must lie on the same radius which is also the radius of the field points In this case both Y and are read with the data The dipole amplitude is the product of the surface current and the incremental area between samples In addition the amplitude of the dipoles on the sides only for positive values of TYPE are reduced by a factor of 2 and those on the corners by a factor of 4 such that the effective aperture of integration has the same size as the specified aperture N3 1 N2 1 N3 N2 S3 Sm e e e e e e o o o 0 o o o e e e o o o e o e 3 N2 e e o o e e 2 N2 e e e o o 3 4 5 6 N2 1 N2 o o o o e o 2 3 N3 1 N2 1 N3 N2 o Oo Oo Oo e e Oo o o Oo Oo o o e Oo o e o o o o o o o e 3 N2 1 o e Oo e e e e e Uz 2 N2 1_2 N2 1 3 N2 o e Oo Oo Oo o Oo Oo Oo N2 1 _N2 2 2 N2 o o o o e o o o o 3 4 5 6 N2 1 N2 e e o o e o Oo S1 uz s2 Figure 9 11 Location of the equivalent dipoles on a planar aperture with negative TYPE December 2002 FEKO User s Manual 9 30 DESCRIPTION OF THE CONTROL CARDS Figures 9 10 and 9 11 show the application of the equivalence principle to a planar aper ture There are respectively N2 and N3 field points along the two ortho
212. ed 2 4 2 Electric symmetry An electric symmetry plane is a plane which can be replaced by an ideal electrically conducting wall without changing the field distribution In figure 2 7 an electric symmetry plane is displayed The electric E field s tangential com ponent disappears and the magnetic H field s normal component disappears The electric current density J is anti symmetric and the magnetic current density M is symmetric As with geometric symmetry less computational time is required to calculate the matrix elements The number of unknown coefficients of the current basis functions are reduced leading to linear equation system of a lower order This leads to a further reduction in the computation time and requires less memory due to the reduction in matrix elements December 2002 FEKO User s Manual 2 8 GENERAL COMMENTS Tod Plane of electric symmetry Figure 2 7 Electric symmetry plane 2 4 3 Magnetic symmetry A magnetic symmetry plane is a plane which can be replaced by an ideal magnetically conducting wall without changing the field distribution In figure 2 8 a magnetic symmetry plane is displayed J M E Plane of magnetic symmetry Figure 2 8 Magnetic symmetry plane The electric E field s normal component and the magnetic FA field s tangential disap pears The electric current density J is symmetric and the magnetic current density M is asymmetric When using magnetic sy
213. elected Cutplanes can be defined to hide selected regions of the model or data Note See the comments on the Apply OK and Cancel buttons in section 3 5 5 7 Under X constant Y constant and Z constant set the position of the cutplane in the available edit box For example under Z constant if the constant value is set to 0 then only geometries in the region Z lt 0 will be displayed Use the slide bars to select different cutplane positions Select Active to make the cutplane active Select Reverse to reverse the region that will be cut out For example with Reverse selected under Z constant constant values set to 0 only geometries in the region Z gt 0 will be displayed Under Entities to cut select the entities on which the active cutplanes must operate It is for example possible to use a cutplane on metallic triangles while wire segments are displayed in the entire region Wire segment unselected Also result data can be left uncut with the geometry cut at the selected plane But currently the Result data option only has an effect on near field data and not far field radiation patterns Remember that the Cutplane option in the Main display panel must be selected for any of the cutplane options to work If you make any modification on the Cutplane options panel and hit the Apply button then the Cutplane option in the Main display panel will be set automatically December 2002 FEKO User s Manual 3 28 THE PROGRAM WINFEKO
214. elected a number of components are available as shown in figure 5 1 Total The total gain independent of the polarisation Vertical The vertical or 9 component Horizontal The horizontal or p component EM Software 4 Systems S A Pty Ltd December 2002 THE PROGRAM GRAPHFEKO 5 13 LHC The left hand circularly polarised component The polarisation vector rotates counter clockwise when viewed at a fixed position in the direction of propagation RHC The right hand circularly polarised component The polarisation vector rotates clockwise when viewed at a fixed position in the direction of propa gation Z 45 deg When viewed in the direction of propagation the y unit vector points downwards and to the left The unit vector for Z polarisation is then z Ea amp V2 which lies along an axis rotated 45 degrees from horizontal in a counter clockwise direction coinciding with the direction of the diagonal line of the Z S 45 deg Here s y amp V2 which is rotated by 45 degrees from horizontal and lies in the direction approximated by the diagonal of the S e Electric field For this only the Theta or g and Phi or p components are available e Axial ratio The axial ratio of the radiated far field as calculated by FEKO A negative sign indicates left hand polarisation The sign is ignored when plotting the axial ratio in dB This option is not av
215. ent for the matrix 48 rows 192 columns 9216 complex numbers For the matrix a memory of NMAT 9216 complex numbers is available Storing the matrix and solving the linear set of equations in main memory A total of 171780 bytes of memory have been allocated dynamically Here the data e g the number of basis functions on the nodes between segments can be extracted It is also indicated how many have the status unknown i e how many have to be determined by solving the matrix equation The maximum number of nodes is also given and this number may not be exceeded 14 2 Excitation The data here is structured depending on the means of excitation For a voltage source on a segment the following data block is generated EXCITATION BY VOLTAGE SOURCE AT SEGMENT Number of voltage source N 1 Frequency in Hz FREQ 7 50000E 07 Wavelength in m LAMBDA 3 99723E 00 Open circuit voltage in V UO 1 00000E 00 Phase in deg ARG UO 0 00 Source at segment w label ULA 1 Absolute number of segment UNR 11 EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE OUTPUT FILE OF FEKO 14 7 If an incident plane wave is used then the output file has the following format EXCITATION BY PLANE LINEAR POLARISED ELECTROMAGNETIC WAVE Number of excitation N 1 Frequency in Hz FREQ 1 9467E 07 Wavelength in m LAMBDA 1 5400E 01 Direction of incidence THETA 180 00 PHI 00 Dir of polarisation ETA 0 00 D
216. ents geometric symmetry 2 The plane z 0 represents electric symmetry 3 The plane z 0 represents magnetic symmetry Is After being mirrored the mirrored parts are given a label it is the previous label with the value of J added to it An exception is label 0 the corresponding new parts will also have label 0 All the conducting and or dielectric triangles segments cuboids tetrahedral volume elements wedges edges Fock regions and polygonal surfaces that have been declared before the SY card are mirrored Furthermore the second and third corners of the triangles are swapped such that the direction of the normal vector is retained Likewise the corners of image polygons are rearranged to retain the normal direction The first corner point of the original polygon becomes the last corner of the mirror image Sources are not mirrored If for example a Hertzian dipole is placed on one side of the symmetry plane the user must also place the correct image on the opposite side of the symmetry plane Multiple SY cards can be used and it is possible to mirror around more than one plane at once e g 2 f3 1 A detailed description of the different types of symmetry geometric electric and magnetic symmetry was given in section 2 4 December 2002 FEKO User s Manual 8 92 DESCRIPTION OF THE GEOMETRY CARDS 8 2 35 TG Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 ty Ig 13 I4 I Ri Ra R3 R4 R5 Re R7 IE R
217. ents of the DELLOOP command are loop numbers The loops entered by mean of a number are deleted Per command a maximum of 10 loops can be deleted Example Delete the loops 1 5 10 and 18 DELLOOP 1 5 10 18 12 3 3 INSLOOP command Using INSLOOP a loop super loop can be created as is required for apertures The arguments are triangle numbers that are to form the loop If more than ten arguments are required a second line can be used without using the command The entry is ended with the command INSEND Example Form a superloop over the triangles 1 15 INSLOOP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 INSEND EM Software 4 Systems S A Pty Ltd December 2002 THE PROGRAM LFFEKO 12 3 12 3 4 END command This command is a necessity and indicates the end of the geo file 12 4 Example The surface current distribution on the surface of a perfect conduction sphere is required The file sphere pre describe the geometry which is shown with the solution of the current in figure 12 1 The file is as follows Sphere with im radius at 50 Hz Excited with a plane wave incident from the z direction and the H field polarised in the y direction Parameters for segmentation IP 0 5 Define points DP P1 0 0 0 0 0 0 DP P2 0 0 0 0 1 0 DP P3 1 0 0 0 0 0 Sphere with centre at 0 0 0 radius 1m KU P1 P2 PS 0 0 0 0 0 180 0 360 0 0 4 End of the geometric input specify low frequency FEKO version EG 1 0 0 1 0
218. er on the fek file associated with the current project The launcher runfeko exe is executed in a command prompt If an output file with the current project name e g dipole out already exists in the current directory path a warning appears before the FEKO solver is executed Select Yes to overwrite the existing output file and No to cancel the Run solver command December 2002 FEKO User s Manual 3 12 THE PROGRAM WINFEKO The FEKO environment variables must be set correctly for FEKO to start successfully from the WinFEKO environment This should have been done automatically by the FEKO installation program See the Getting Started manual 3 5 4 Running the parallel version of FEKO On Windows NT 2000 XP systems the parallel version of FEKO is also launched from the Solve menu in WinFEKO It uses MPICH NT for the communication between the different hosts nodes Both FEKO and MPICH NT must be installed on all the PCs in the cluster and the executable feko csv exe must be located in the same directory on each node If FEKO is installed with parallel support MPICH NT is installed automatically The parallel version of FEKO must be activated on all the nodes in the cluster and WinFEKO must be activated on the local PC The current user on the PC where the job is launched must have an account on all the machines where he intends to start the parallel job All these accounts must use the same password 3 5 4 1 Configuring MPICH Befo
219. er suggestion 5020 26 264 bu Sa a woes 4 4 423 Variablecditor ooo 00 2 204 4 5 428 BAM MIM 6 ob a E eee eee eet ede dea 4 5 Ao SOPOT on 6G oo de ae ee oe SEER ED aE aa Sw Gass 4 6 Lab RUM oo bee eee ek Bee dr 4 6 43 OQOPTFEKO mode ico mua iE iaaa sean deed ade beau 4 6 44 Important keystrokes qaaa be ee oE aa daia anaa 4 7 EM Software amp Systems S A Pty Ltd December 2002 CONTENTS iii 5 The program GraphFEKO 5 1 DL Ramps GropiFERG naa a ra e e e a A 5 1 5 2 Toolbars in GraphFEKO 2 54 panie eget a sy ewe a 5 1 5 2 1 FILE control toolbar gt gt sea aedd onra naad a dau 5 1 52 2 Data extraction toolbar co a a e 5 2 Da Main menu structure 6 cnis ec a ai 5 2 Gad File Mem e cc cca aa a een bbe bee a a Bees 5 2 Daa DMPO NN 5 5 A AE 5 16 5 3 4 Tools menu Line arithmeticS 5 19 5 3 5 Tools menu Unwrap phase 5 20 5 3 6 Window menu raria dai 5 20 Soot o pie eee Se ee 6d eee Se ee PSL Se ee 5 21 6 The preprocessor PREFEKO 6 1 wL IDAS a cde de ceed O se ee ws a ew Bk A 6 1 62 Running PREFEKO 0 6 eee cae ewe eee aw wad 6 1 6 3 Symbolic variables ocios ms s 6 1 G4 FOR NEXT loops eco dia bbe ee a aa 6 6 6 5 IF ELSE ENDIF constructs e e 6 8 68 Symbolic nod mames Ga ee ee Re aa 6 9 6 7 PRINT and EXIT commands so s s a aai 6 ow ns ss 6 9 8 Copyright to Voronoi os s s ee a e e os ee RR ee i 6 10
220. ers S1 Name of any corner of the cuboid S2 Second corner of the cuboid see above S3 Optional third corner of the cuboid see above S4 Optional fourth corner of the cuboid see above EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 87 only applicable to dielectric cuboids Ri Relative dielectric constant e of the dielectric cuboid R2 Conductivity o in gb of the cuboid R3 Density o in E of the cuboid This value is only required for calculat ing the SAR specific absorption rate but must always be declared Re The electric loss tangent tan only applicable to magnetic cuboids R Relative permeability ur of the magnetic cuboid Rs Loss tangent tan of the magnetic cuboid where Mr Hp je u 1 j tan No dielectric bodies with surface equivalence principle and volume equivalence principle using cuboids can be used at the same time Example of QU card usage Using the following commands the dielectric cuboid shown in figure 8 52 is generated OK IP DP DP QU EG EN 1 1 A 1 0 0 0 0 0 B 7 0 3 0 1 5 A B 5 0 0 0 Figure 8 52 Example for the QU card December 2002 FEKO User s Manual 8 88 DESCRIPTION OF THE GEOMETRY CARDS 8 2 32 SF Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 SF KA SKAL LA INT INT INT INT INT STR STR STR STR STR REAL REAL REAL REAL REAL REAL REAL REAL With this card the scaling of the ge
221. erted as the argument of the new function Variables operators and the FILEREAD function replace the currently selected text 4 2 4 Edit menu Besides the standard Windows functionality this menu provides the Insert file menu to copy the contents of another file to the current cursor position It also provides access to the card editor for the current line The Edit Undo option will undo the last change to the editor only Selecting it again will just undo the effect of the Undo command The items Edit Comment and Edit Uncomment allow the user to comment out blocks of text or remove the comments This is often useful when debugging large files The comments are inserted as followed by a space and only removed if this sequence is present December 2002 FEKO User s Manual 4 6 THE EDITOR EDITFEKO For example in the lines k Select the label LA 1 Next comment the comment characters will not be removed from the third line using this function It was also not generated by the Comment function These commands are also available using the hot keys lt Alt gt lt C gt for Comment and lt Alt gt lt U gt for Uncomment or by right clicking in the editor and selecting from the resulting pop up menu 4 2 5 Search menu It is possible to search the editor for specific text case sensitive or not The search always starts from the current cursor position If it is desired to start the search from the t
222. es this value is sensible If scaling is done with the SF card this value is also scaled It is recommended to specify EPSENT only if FEKO demands it i e if a warning or an error message is given Otherwise the default should be used EPSR The relative dielectric constant e of the homogeneous medium in which all structures are contained When this field is empty Er is set to 1 MUER The relative permeability ur of the homogeneous surrounding medium When this field is empty pu is set to 1 SIGMA The conductivity in of the homogeneous surrounding medium When this field is empty is set to 0 TANDMUE Magnetic loss factor tand of the homogeneous surrounding medium the complex permeability is then given by H lor 1 jtand TANDEPS Electrical loss factor tan of the homogeneous surrounding medium This is an alternative way to specify the conductivity to which it is related by tan d The exact meaning of the parameter EPSENT is the following The program PREFEKO creates a fek file in which all the triangles and segments are described by their corner points Due to rounding errors it is possible that for example end points of connecting segments do not coincide When searching for nodes an ohmic connection is made when the difference is smaller than the parameter EPSENT FEKO automatically checks for typical user errors that have been observed in the past Examples of errors are connecting a wire segment to the middle
223. f WinFEKO or older fek files Other Under Batch files select Call IntFEKO to explicitly add a call initfeko bat line every time PREFEKO or FEKO is run from within Win FEKO This is only useful on systems where FEKO has been installed and the appropriate path and environment variables could not be set due to file write re striction for example when changes to the autoexec bat file is not allowed on a system Under Default Selection Option select the default option that must be used when picking a model entity Under FEMAP version select the version of FEMAP if any installed on your system This is necessary for WinFEKO to create the correct FEMAP mod file when a new WinFEKO project is created If None is selected here WinFEKO will not create a FEMAP mod file at all Under 3rd Party CAD String select the path and string as well as extension of a third party CAD program that must be executed instead of FEMAP with the FEMAP execute button The specified extension is added to the current project name and this is passed as parameter to the specified executable This third party CAD program will be executed only if the Active checkbox has been selected It is possible to replace one of the default FEMAP model files with a model file for the specified CAD program these are located in the Defaults FEMAP subdirectory of the FEKO installation Note Remember to hit the Apply or OK button for the changes to take effect and the C
224. f metallic triangles and triangles that represent the surface of the dielectric Another special case is when metallic triangles represent the surface of a dielectric object e g a dielectric that has been coated with metal All the segments that follow this card are assigned the properties of the medium in which they are found Triangles are treated differently it depends upon whether they are metallic triangles or triangles on the boundary of a dielectric object Here the properties of the media are assigned to the respective sides Parameters There are a number of different cases e Fields S2 and S3 empty S All the geometry cards generating segments and triangles that follow this card are assigned the medium properties with the in dex Si Si 0 is for the special case where the triangles and segments are situated in free space e Fields S2 occupied and S3 empty S1 S2 All segments generated after this card are situated in the medium S All the triangles represent a boundary between dielectric ob jects The normal vector points from medium S to medium S2 Note that the user should ensure that the normal vectors of the triangles are in this direction It is recommended to use Win FEKO to validate the geometry e Field S3 occupied Si S2 All triangles generated after this card are metallic triangles that are situated on the surface of a dielectric object between the media S and S2 The normal vector points from medium S
225. f no penalty functions are to be assigned at all then the whole section can be left out Example PENALTY_FUNCTION 100 100 10 10 10 3 3 Definition of the optimisation process There are a number of optimisation processes that can be used with OPTFEKO Discrete points This method is strictly speaking not an optimisation method The optimisation param eters are linearly varied between their minimum and the maximum values The value of the aim function is calculated at n discrete points The process is selected using the keyword RASTERSUCHE or GRID_SEARCH The number of discrete points required for each optimisation parameter is specified in the line following the keyword Example GRID_SEARCH 8 9 In this case the aim function will be determined 8 9 72 times Eight discrete points for the first optimisation parameter and nine discrete points for the second optimisation parameter December 2002 FEKO User s Manual 10 4 THE OPTIMISER OPTFEKO Simplex method Here the so called Simplex is assigned through space over the normalised 0 1 opti misation parameters and the minimum is searched for In the row that follows the keyword SIMPLEXVERFAHREN or SIMPLEX_METHOD four param eters need to be specified The first indicates the basis of the Simplex in the normalised space If the Simplex starts rotating around a minimum its basis will be scaled down by the factor given by the second parameter The third parameter is
226. f the field strength Es of the incident field in degrees EIR3 Angle of incidence Y of the plane wave in degrees see figure 9 3 EIR4 Angle in incidence y of the plane wave in degrees see figure 9 3 EIR5 Polarisation angle 7 in degrees see figure 9 3 DTHEI If more than one direction of incidence is to be examined then this value is the increment in the direction of incidence in the Y direction DPHII If more than one direction of incidence is to be examined then this value is the increment in the direction of incidence in the y direction EIR8 Axial ratio v of the polarisation ellipse in the range 1 1 with the following meaning v 1 LHC left hand circular polarised incident wave 1 lt v lt 0 Elliptical polarisation with axial ratio v left hand rotating v 0 Linear polarisation 0 lt vw lt l Elliptical polarisation with axial ratio v right hand rotating v 1 RHC right hand circular polarised incident wave EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 9 Figure 9 3 Direction of incidence Bo and direction of polarisation 7 of the incident field The direction of incidence Bo is specified by the incidence angles Y and p The polarisation angle 7 measured from the negative of the spherical coordinate system unit vector V and the field strength vector Ep is defined as indicated in figure 9 3 The electric field strength of the incident field is then given
227. f the following bitmap based graphics file types e Bitmap Prints to a bitmap file with extension bmp The bitmap file created could be quite large in memory for Presentation mode printing e Jpeg Prints to a jpeg file with extension jpg A jpeg file will be much smaller in memory than a bitmap file but picture quality will be lost e Gif Prints to a gif file with extension gif A gif file is a good choice Much smaller in memory than a bitmap file but better quality than jpeg e Eps Prints the bitmap to an image embedded in an encapsulated postscript file eps These eps files can become very large as it is a bit by bit representation of what is on the rendering screen encoded into the postscript language e Tif Prints to a tif file with extension tif A tif file is of good qualtity but could similar to a bitmap be quite large Also available from the Save as type drop down list is one of the following vector based graphics file types The image created with vector based printing would not necessary appear exactly as on the rendering screen in WinFEKO e Vector Postscript This creates a vector based postscript file ps from all the objects in the WinFEKO model that represents as close as possible the image rendered on the screen e Enhanced Metafile Same as vector based postscript printing but printing to an Enhanced Metafile emf e Metafile Same as vector based postscript printing but printing to a
228. f the half axis is too extreme for example if the longest half axis is a factor 100 longer than the shortest It is strongly advised to check the geometry with WinFEKO EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 27 S Direction 9 0 S ae 3 Direction S4 p 0 Figure 8 18 Sketch illustrating the use of the EL card Example of EL card usage The following commands generate the eighth of an ellipsoid as shown in figure 8 19 kk IP DP DP DP DP EL EG EN rFUoUQwn se O On O Figure 8 19 Example for the EL card December 2002 FEKO User s Manual 8 28 DESCRIPTION OF THE GEOMETRY CARDS 8 2 14 FO Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ri Ra TA ae ee ae NT REAL REAL REAL REAL REAL REAL REAL REAL With this card an area is defined in which the surface current density is an approximation according to the Fock theory Parameters S Type of Fock area 1 Ideal conducting cylinder 2 Ideal conducting sphere S2 Label of the metallic triangles that form the surface of the Fock area e g the surface of the cylinder S3 Centre of the sphere for S 2 or begin point of the axis of the cylinder for S 1 S4 Only defined for S 1 the name of the end point on the axis of the cylinder Ri Type of process for the Fock currents 0 Method by Daniel Bouche 1 Method by Louis N Medgyesi Mitschang R 0 Usual opt
229. f wire grid surfaces and it would be more efficient to convert the models to FEKO surfaces but this cannot be done automatically In this case the syntax is IN 5 filename nec IN 5 filename nec 3 IN 5 1 filename nec 3 7 scaling 0 001 The label selection uses the NEC tags which are converted to FEKO labels This applies to the tag when the element is defined If the tag is modified after the inclusion for example with the GM card the elements with the modified tag are also included Again scaling is supported The type selection parameter x is also supported but it may only have the value 1 for wire segments The NEC import filter considers only the geometry cards CM CE GA GW GM GR GS GX and GE A warning is given if other cards are encountered If the model contains multiple geometries only the first one is read 6G J Burke and A J Poggio Numerical Electromagnetics Code NEC Method of Moments Lawrence Livermore Laboratory January 1981 EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 43 e FLAG 6 Import of Concept geometry files With this option one may import Concept geometry files Since Concept uses two different files for wires and surface elements the type selection parameter x is obligatory and determines the type of geometry file to be read IN 6 1 concept_wire dat IN 6 34 concept_surface dat scaling 1000 The selection parameter must be eit
230. fect for wires and or surfaces that is valid at arbitrary frequencies 4 Treat metallic triangles as thin isotropic dielectric layers possibly consisting of multiple layers 5 Treat metallic triangles as thin anisotropic dielectric layers possibly consisting of multiple layers for Iz 1 2 or 3 R The thickness d of the surface elements in m if an SF card is present this is scaled independent of the value of SKALFLAG R The relative permeability ur of the material R The conductivity o in yz Rz Magnetic loss factor tan the complex permeability is then given by u Lol 1 jtand for Ip 4 I3 The number of layers If this field is empty 0 or 1 there is just one layer R The thickness d of the first layer in m if an SF card is present this is scaled independent of the value of SKALFLAG Ra The relative permeability ur All layers must have the same perme ability R3 The conductivity o in of the first layer Rs The loss factor tan tan _ of the first layer WEQEr Rg The relative dielectric constant e of the first layer December 2002 FEKO User s Manual 9 90 DESCRIPTION OF THE CONTROL CARDS Rz Magnetic loss factor tan 6 the complex permeability is then given by Lt Lofr 1 j tan 6 All layers must have the same permeability now follow J3 1 lines with the parameters of the remaining layers this approximation is such that it is independent of the order of the
231. field and currents picking the corresponding data must have been loaded and displayed in the model view window For geometry and vertex picking a geometry model must be visible in the model view window EM Software 4 Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 31 Note With the Far Field Near Field and Currents Option panels visible picking for the corresponding far field near field and current objects are automatically selected under the Picking Options Right click anywhere on the background of the model view window i e not on any geometry or data object to erase the displayed information enabled by picking 3 5 8 Options menu 3 5 8 1 General settings Here a number of general program options can be set All of these options can be saved to a configuration file The default configuration file is winfeko cfg If this file is present in the FEKO home directory these settings will be the default settings that WinFEKO starts with It is however important to note that some of these settings are also saved in the project file wfp associated with each WinFEKO project In other words on startup WinFEKO loads the settings from the winfeko cfg file When a project is loaded the wfp file is loaded if it exists and some general settings associated with the specific project overrides the default WinFEKO general settings To change the default WinFEKO configuration file make the appropriate changes under all Gene
232. file This card is used to import models generated by the commercial CAD meshing program FEMAP The models must be exported from FEMAP in the neu FEMAP neutral file format The syntax is then IN 1 part_i neu IN 1 part_2 neu 5 IN 1 7 part_3 neu 7 10 scaling 0 001 The label selection uses the FEMAP layer numbers which are converted to FEKO labels Note that scaling is supported The type selection parameter x is supported and may have the following values 1 Wire segments 2 Surface triangles 4 Polygonal plates 8 Tetrahedral volume elements 16 Node points 32 Quadrangles divided into triangles Wires must be meshed into elements which are imported as segments surfaces into triangles or quadrangles which are imported as FEKO triangles and boundary surfaces are imported as polygons The boundary surface must be bordered with line curves rather than edge curves The user can also elect to import points from the neu file All points defined as such in FEMAP are then available in PREFEKO as points as if they were defined by DP cards of the form Pxxx where xxx is the point ID in FEMAP This may be used for example when attaching additional structures to a geometry partly created in FEMAP In addition the coordinate values of the point are available as variables in PREFEKO For example the variables p1234x p1234y and p1234z give the coordinates of the FEMAP point with ID 1234 Note that points are not included by defaul
233. following way pi 3 1415 2pi 2 pi vara 1 sqrt 2 varb vara 2 3e 2 sin pi 6 sin rad 40 ttvara 2 summe varat varb Note that the sign has to appear in the first column On the right hand side of any expression variables that have already been defined can be used in conjunction with any of the following functions 0 brackets addition subtraction multiplication division k powers for example 273 8 SIN sine argument in radians COS cosine argument in radians TAN tangent argument in radians COT cotangent argument in radians ARCSIN arcsine in radians ARCCOS arccosine in radians ARCTAN arctangent in radians ATAN2 this function has two arguments atan2 y x it yields arctan y x in the range 7 7 ARCCOT arccotangent SINH hyperbolic sine COSH hyperbolic cosine TANH hyperbolic tangent SQRT square root LOG logarithm to the base 10 LN natural logarithm EXP exponential function ABS absolute value DEG convert radians into degrees RAD convert degrees into radians STEP step function i e STEP x 0 for lt 0 STEP x 1 for x gt 0 CEIL smallest integer value that is equal to or greater than the argument FLOOR largest integer value that is equal to or smaller than the argument EM Software amp Systems S A Pty Ltd December 2002 THE PREPROCESSOR PREFEKO 6 3 MAX returns the largest of the two arguments called as max a b MIN returns the smallest of
234. from the fek file and displayed If not the message No FEK file available for this project is displayed at the bottom of the display screen Run PREFEKO to create the fek file 3 5 1 3 Close project Select Close project to close the current project The project information is saved in the wfp file WinFEKO releases all memory allocated when the project was opened the fek file was loaded and or the output file information was loaded 3 5 1 4 Save project Select Save project to save settings associated with the current project The settings such as zoom factor view angle pan position axis length cut planes and all the display options on the Main display options panel are saved in the wfp file December 2002 FEKO User s Manual 3 8 THE PROGRAM WINFEKO 3 5 1 5 Save project as Select Save project as to save the project under a new name This is very different than Save project Here a new directory is created for a completely new project Decide on the name the project should be saved as Type it into the Project name edit box A new directory will be created in the selected path use the Browse button to select the path if necessary The name of the new directory will be the selected Project name For example if the current project name is dipole and the new or save as project name is selected as dip_2 then a new directory dip_2 will be created Decide on the Copy options Three different options are availabl
235. ft lt Ctrl gt lt Left Arrow gt Move a word right lt Ctrl gt lt Right Arrow gt Move to top of visible page lt Ctrl gt lt Page Up gt Move to bottom of visible page lt Ctrl gt lt Page Down gt Move to beginning of line lt Home gt Move to beginning of line lt End gt Move to beginning of file lt Ctrl gt lt Home gt Move to end of file lt Ctrl gt lt End gt A block may be selected using the mouse or pressing lt Shift gt and using the normal movement keys If a block is selected it will be overwritten when a key is pressed The following list of hot keys are often used Hot keys Copy to clipboard lt Ctrl gt lt C gt or lt Ctrl gt lt Ins gt Cut delete to clipboard lt Ctrl gt lt X gt or lt Shift gt lt Del gt Paste insert from clipboard lt Ctrl gt lt V gt or lt Shift gt lt Ins gt Save lt Ctrl gt lt S gt Save all files lt Ctrl gt lt A gt Save and exit lt Alt gt lt X gt Edit line lt F1 gt Comment line s lt Alt gt lt C gt Uncomment line s lt Alt gt lt U gt Find lt Ctrl gt lt F gt Find next lt F3 gt Find and replace lt Ctrl gt lt R gt Run PREFEKO lt Alt gt lt 2 gt Run WinFEKO lt Alt gt lt 3 gt Run FEKO lt Alt gt lt 4 gt Right clicking with the mouse on a card panel button searches for the next occurrence of that card Right clicking in an input dialog box presents a list of possibilities 4Note that only fields entered above the current cursor line are used
236. fy where to calculate the fields e The EN card which signifies the end of the input file When the card editor is selected from either the button panel of the menu there is an option to Add card This adds the card without closing this editor This is useful when defining a number of similar cards for example when specifying the first group of DP cards at the start of a model Often only one or two parameters differ between cards Pressing lt Enter gt has the same effect as clicking on the Add card button Similarly lt Esc gt closes the card editor as if the Cancel button has been clicked In the card editor moving the mouse pointer over the labels may give more information of the specific input field If the user is uncertain about the meaning or units of a given field it is always advisable to move the mouse pointer to the label to determine if any additional information is available December 2002 FEKO User s Manual 4 4 THE EDITOR EDITFEKO All the input fields in FEKO have a fixed length In the card editor it is not possible to enter longer strings than allowed for the particular field Note however that spaces in the input field may be overwritten by new keys when the input field has maximum length If the cursor is at the end of the field or at any character other than a space no new keys are excepted once the maximum length is reached Then it is necessary to delete characters before any additional ones can be entered Edit
237. g systems a pppoe enea dda na a aaa 00048 3 1 3 1 2 Memory requirements o sorer ewura ra iry aaya 3 1 31 3 Display settings aa ia onedd ee cakk a a aa g 3 1 LA Graphics card eaaa ee ee ee a aa e 2 3 2 3 amp 2 Ruming WnFEKO ees ao ea eee k ee a aa 3 2 33 Hot keysia W FEKO cca aapa aisla aai 3 2 December 2002 FEKO User s Manual ii CONTENTS 34 Toolbars in Wina FEKO 02 44 4 005 e eee toerana aa nasd 3 3 eA FILE control toolbar cso aaa 6 bobo be ee wee RE EES 3 3 34 2 FEKO control toolbar gt gt gt o o se sasda saadama ee 3 4 3 4 3 DISPLAY OPTIONS control toolbar 3 4 44 RESULTS control tocdlbar o 3 5 3 45 RENDER control toolbar 3 5 g0 Main meny SUCTUS coccion e a 3 6 SoL AA 3 6 39 2 Preproc dsine MEL o kae aa a ee aa a 3 10 A a he ee a a a a a ee 3 11 3 5 4 Running the parallel version of FEKO 3 12 eo REUS DIS lio o o p e a a a as as Ra da Ada 3 13 3200 Display MENU se ecran aa a be aa a ea ee 3 23 Sd Toob menu cos e a de de o 3 29 eas puns MEDU osa a aa 3 31 9409 Help memi oes eceu a a be de a ee ee ee 3 33 4 The editor EditFEKO 4 1 DL Generale e ac ee eee a a a se a e a a a e a 4 1 AAA UG GME ocea aan ira a a oe Coe 4 1 LUZ Options MEDU sr ac aa AA 4 2 4 13 Window mem ca ea coca coed ee be thee eee es 4 2 ALA Helen ccoo aa 4 2 42 PREFEKO mode oo oe ae eee eR EE AAA 4 2 4 2 1 Generating input cards 2 4 osc d 66 6 eee eee ees 4 2 4 2 2 Paramet
238. gential electric field is zero while the magnetic field is not thus we will use electric symmetry For this example the field is considered to be purely y directed i e it has only a y or s component The field is assumed to be constant in the y direction and to have a cosine distribution in the x direction i e the s axis Figure 9 14 Example of an open waveguide as an implementation of the AP card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 33 With N2 5 and N3 3 in practice more points may be required the data file will be as follows 0 0 0 0 0 0 0 0 0 0 0 0 0 707 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 707 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 707 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 707 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 707 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 707 0 0 0 0 0 0 0 0 0 0 The zero values will not result in any dipoles but they must be in the data file to allow correct indexing The pre file will contain the following section Only electric fields use electric symmetry in the z 0 plane SY 1 0 0 2 Define the corner points of the aperture wx 0 02286 wy 0 01016 DP P1 wx 2 wy 2 0 DP P2 wx 2 wy 2 0 DP P3 wx 2 wy 2 0 The geometry ends after the corner nodes have been defined EG 1 0 0 0 0 Specify the frequency FR i 0 9 375e9 Specify the AP card as a new source The amplitude factor of 2 0 is due
239. gion with or without a hole is created It is also possible to distort it to an elliptical region A sketch is shown in figure 8 29 a S b S Figure 8 29 Sketch illustrating the use of the KR card Parameters S Name of the centre point of the circle S2 The name of a point that is situated at any distance perpendicular to and above the plane of the circle S3 The name of the point where the arc of the circular segment begins S4 If there is a value present for this parameter then a circular ring is created Sy is the inner corner point S4 must lie between S and S3 Ri The angle vy in degrees subtended by the arc R The maximum edge length of the triangles along the outer edge of the arc in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used R When a disk with a hole is created the maximum edge length for the triangles along the inner edge of the arc in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 57 Ra If this parameter is empty or is set to 1 a circular disk is created Within certain limits the parameter R4 may be used to generate an elliptical disk R4 2 gives the ratio of the two half axes where a is the distance S S3 It is recommended to generate ellipses with extremely small or extremely la
240. given above will run with 4 processes on host1 and 2 on host2 If on one host only one process shall be started then instead of the entry host3 1 in the machines file also the shorter form host3 can be used Such a machine file the file mpi share machines feko under the FEKO installation path FEKO_HOME is automatically created during the installation of the parallel version of FEKO By default FEKO uses this file If a different distribution of the processes is required one can edit this file manually This is however strongly discouraged The user should rather create a separate machines file with the syntax described above If this file is for example machname the environment variable FEKO_MACHFILE is used to force RUNFEKO to use this file instead of the default The required commands for the sh shell are FEKO_MACHFILE machname export FEKO_MACHFILE runfeko example_08 np 6 EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM FEKO 7 3 Alternatively one may pass the name of the machines file as an argument to RUNFEKO runfeko example_08 np 6 machines file mymachines Using RUNFEKO is independent of the respective platforms and MPI implementations see also the discussion of the environment variable FEKO_WHICH_MPI in section 2 7 For very special applications or experienced users it may be necessary to pass additional options to MPI In such a case the appropriate MPI manuals located in the subdirec
241. gles in this case p4 is 0 and quadrangles TA MoM code developed at the University of Hamburg Harburg Germany December 2002 FEKO User s Manual 8 44 DESCRIPTION OF THE GEOMETRY CARDS e FLAG 7 Import of triangular data from STL files PREFEKO can also import STL both ASCII and binary files STL files support only triangular patches and these are all imported Therefore the selection parameter x does not make sense and is not supported Also since the STL file makes no provision for any labels label selection is not supported The syntax is IN 7 IN 7 file stl file stl scaling 0 001 Note that scaling is supported An example of an ASCII STL file is SOLID CATIA STL PRODUCT FACET NORMAL 4 602166E 01 1 858978E 01 8 681260E 01 EM Software amp Systems S A Pty Ltd OUTER LOOP VERTEX 4 789964E 01 8 440244E 01 2 878882E 01 VERTEX 4 764872E 01 8 439470E 01 2 892018E 01 VERTEX 4 783065E 01 8 414296E 01 2 876983E 01 ENDLOOP ENDFACET FACET NORMAL 4 601843E 01 1 859276E 01 8 681367E 01 OUTER LOOP VERTEX 4 764872E 01 8 439470E 01 2 892018E 01 VERTEX 4 761175E 01 8 425569E 01 2 891001E 01 VERTEX 4 783065E 01 8 414296E 01 2 876983E 01 ENDLOOP ENDFACET ENDSOLID For the description of binary STL files please see http www ennex com fabbers StL asp http rpdrce ic polyu edu hk old_files stl_binary format htm FLAG 8 Read a CADFEKO model file This option is used to import models genera
242. gonal directions For positive values of the parameter TYPE the first point lies at S with the following points in the direction of Sa as shown by the indices in figure 9 10 For negative values of TYPE the pattern is as shown in figure 9 11 The normal vector is calculated from n z X tg with us and s as defined in the figure Z Z S2 S2 g gt eje HH aes i s e a b e 7 5 SA X Q b Figure 9 12 Location of the equivalent dipoles on a cylindrical aperture a Positive TYPE b Negative TYPE For cylindrical and spherical apertures PREFEKO will determine which coordinate is incremented first and write out the dipoles accordingly Figure 9 12 shows the dipole locations for a cylindrical aperture created from a data file containing field values for py from 20 to 80 in 10 increments and 5 values in the z direction When TYPE is positive such that samples lies up to the edges of the aperture the points and the effective aperture is a shown in figure a When TYPE is negative samples does not lie on the edges as shown in figure b Note that when using identical input data as for positive values of TYPE the z positions of the samples changed while in the y direction the size of the effective aperture is increased by 5 on both sides Figure 9 13 shows the dipole locations for a spherical aperture created from field values for Y from 40 to 80 with 10 increments and y from 20 to 80
243. he Add card button is not available as the card is edited and written back to the editor The card editor will keep the last parameters entered even if it is closed until a different type of card is edited In this case pressing lt Enter gt has the effect of clicking the OK button The card editor does not edit cards generated by PREFEKO such as the DR card The user should rather use the input cards that are read and converted by PREFEKO Generally it should not be necessary to use cards that are not available in EditFEKO It should finally be noted that while the card editor is open no other action is allowed It is not possible to resize the window or hit the close button marked on the top right corner 4 2 2 Parameter suggestion While using the card editor right clicking on the input field dialog boxes presents a list of suggested values This may be either point or element labels depending on the card and the input field for the integer parameters or a list of variables for the real input fields EM Software 4 Systems S A Pty Ltd December 2002 THE EDITOR EDITFEKO 4 5 The list is constructed as PREFEKO would read it i e only the labels or variables defined above the current line are used They are listed in the order that they are specified by the input cards Unless they are sorted using the Options Sort drop down list menu option For the list of variables the predefined variables see page 6 5 are listed firs
244. he corner points have to be defined by a DP card prior to the PM card The point names are specified in the first four string parameters columns 6 10 11 15 16 20 and 21 25 and the first nine real parameters columns 31 40 41 50 111 120 The point names may not be longer than 5 characters but may be aligned at any position in the 10 character real fields If non uniform meshing is required the mesh size along each edge is specified in the next 13 real parameters columns 121 130 131 140 241 250 where the first mesh size refers to the edge from the first to the second point the next to the edge between the second and third point etc There may only be as many mesh sizes as node points and the last size refers to the edge from the last listed node point to the first point If any edge size is left empty the value specified with the IP card will be used The user can also specify internal mesh points for example to create connection points If the parameter J is set to 0 no internal mesh points are specified If J 1 a second line which specifies up to 26 internal mesh points specified with DP cards prior to the PM card must follow the PM card The point names are specified similar to the points in the first line except that there are 22 real fields instead of just 9 EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 79 Example of PM card usage The commands below generate
245. he current distribution Here the following data is given for each triangle VALUES OF THE CURRENT DENSITY VECTOR ON TRIANGLES in A m Triangle centre JX JY JZ number x m y m z m magn phase magn phase magn phase 1 944 000 056 1 644E 03 19 10 0 000E 00 00 3 716E 02 162 73 2 889 000 111 1 184E 03 163 01 0 000E 00 00 3 238E 02 157 26 3 944 000 222 4 709E 03 12 49 0 000E 00 00 2 784E 02 149 11 4 889 000 278 2 032E 03 170 73 0 000E 00 00 2 081E 02 119 69 5 944 000 389 4 285E 03 13 23 0 000E 00 00 2 083E 02 100 40 Current magnitude in the 3 corner points 850E 02 3 882E 02 3 457E 02 145E 02 3 169E 02 3 445E 02 143E 02 3 446E 02 2 197E 02 109E 02 2 234E 02 2 146E 02 106E 02 2 467E 02 2 291E 02 NN WW W At the position x y z the current density vector J in the complex form is given The last three columns indicate the value for the surface current density in the three vertices of the triangles where the value is the average of the current at the vertices of all three adjacent triangles If the current is requested the charge on each triangle is also written to the output file Only the charge is given as the position of each triangle is the same as written for the currents VALUES OF THE SURFACE CHARGE DENSITY ON TRIANGLES in As m 2 Triangle SIGMA number magn phase 1 2 50469E 13 56 08 3 55072E 13 42 60 3 9 33040E 13 54 20 December 2002 FEKO User s Manual 14 10 DESCRIPTION OF THE OUTPUT FILE OF
246. he density o in E of the sphere This parameter is only required to calculate the SAR specific absorption rate but it is compulsory i e it must be defined R7 The electric loss tangent tan 0 Only applicable to a magnetic sphere Rs Relative permeability ur of the magnetic sphere Rg The magnetic loss factor tan d No dielectric bodies with surface equivalence principle and volume equivalence principle using cuboids can be used at the same time EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 19 Example of DK card usage Using the following commands an eighth of a sphere as shown in figure 8 15 is created xk IP 0 1 DP A 0 0 0 0 0 0 DP B 0 4 0 0 0 0 DP C 0 0 0 4 0 0 DP D 0 0 0 0 0 4 DK A B C D 0 06 4 0 0 0 1000 0 EG EN Figure 8 15 Example for the DK card December 2002 FEKO User s Manual 8 20 DESCRIPTION OF THE GEOMETRY CARDS 8 2 10 DP Card S Ri Ra R3 R4 A IE REAL REAL REAL REAL REAL REAL REAL REAL With this card points in space are defined To avoid ambiguity each point is assigned a name a 5 character string In the other commands e g BL card the points are referred to by their names Parameters S Name maximum of 5 characters of the point Ri x coordinate of the point in m is scaled by the SF card R y coordinate of the point in m is scaled by the SF card R3 z coordinate of the point in m is scaled by the SF card
247. he display screen 9 Pan up by a constant factor The default constant factor is 10 100 represents panning vertically across the display screen 10 Pan down by a constant factor The default constant factor is 10 100 represents panning vertically across the display screen 11 Increase Phi view angle by a constant factor 15 degrees 12 Decrease Phi view angle by a constant factor 15 degrees 13 Increase Theta view angle by a constant factor 15 degrees 14 Decrease Theta view angle by a constant factor 15 degrees 3 5 Main menu structure 3 5 1 File menu This is used for project or file and printing control 3 5 1 1 New project Select this item to create a new FEKO project On selection the Create new project panel is activated Decide on a name for the new project for example dipole and enter it into the Project name field The name can be longer than 8 characters Type the directory path in the Project directory path field or Browse to select a directory path EM Software 4 Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 7 Decide on the type of problem Three different templates are available at present e The Radiation template will create a FEKO input file pre file with the control cards typically used with radiation problems e The Scattering template will create a FEKO input file pre file with the control cards typically used with scattering problems e The None tem
248. he horizontal axis of the graph e Line settings Select the line to edit from the Line nr drop down list On selection the basic line settings will be displayed under Caption Colour Marker and Style Type the required legend caption for each line in the Caption edit box The legend for the corresponding line will change on the active graph if the Legend option is selected under Graph settings Choose a line colour line marker and line style from the Colour Marker and Style drop down lists T he corresponding line will change on the active graph The Visible option is checked selected by default for each line Unselect the Visible checkbox to hide not delete a specific line The Scaling option allows the user to add a constant scaling factor to the data on the vertical axis and offset adds a constant offset to the data such as required December 2002 FEKO User s Manual 5 18 THE PROGRAM GRAPHFEKO for scaling dB graphs This is useful for example to view small currents in mA rather than A The scaling factor is not cumulative and each time it is changed the new factor is applied to the original data When Normalisation is selected all plots are scaled before they are normalised Scaling only influence normalisation to the graph maximum but if an offset has been added normalisation yields a different result More line setting options are available under advanced editing e Bottom axis Click the Bottom axis button to set the
249. he origin of the Cartesian coordinate system x 0 y 0 and z 0 Enter the Cartesian coordinate point around which the model must be rotated in the appropriate x y and z edit boxes in metres If a vertex or geometry entity is selected the Selected Entity button will become enabled Click it to fill the x y and z edit boxes with the coordinates of the selected entity Click the Model Centre button to fill the x y and z edit boxes with the coordinates at the centre of the model under display 3 5 7 3 Render test Select this menu item to open the Render Test window This window display informa tion about the OpenGL rendering hardware and software on the system at hand Click the Start Test button to start the render test for render speed comparison to other systems 3 5 7 4 Entity Selection With this menu item any of Geometry Vertex Near Fields Far Fields or Current entity selection can be activated The Entity Selection panel is enabled Note See comments on the Apply OK and Cancel buttons in section 3 5 5 7 Under Picking Display Options select the way the picked geometry element will be displayed on screen This is similar to the display options discussed in section 3 5 7 1 Under Picking Options select the type of entity that must be highlighted displayed when clicking on the model and or data on the display screen To pick an entity the user must right click on the appropriate geometry or data object For far field near
250. he same meaning as Ro Rs Height of the end cap on the S2 only applicable when Ry 2 or R4 3 in m is scaled by the SF card Example of UZ card usage The following commands generate the cylinder in figure 8 57 Example of a cylinder in UTD region DP A 0 0 2 DP B 0 0 2 DP C 1 0 2 UZ A B 0 360 0 0 EG EN Y as Figure 8 57 Example for UZ card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 103 8 2 40 VS Card KA 6 10 15 20 25 30 40 50 60 70 80 90 100 110 ABSFLA ILABI LAB2 NT NT R mT NT REAL REAL REAL REAL REAL REAL REAL REAL This card specifies visibility information to reduce the time required to calculate the visibility information required when using physical optics with multiple reflections To accurately compute multiple reflections the code needs to determine which basis func tions are visible to each other For large problems this may be very time consuming The time required to determine the visibility may be greatly reduced if the user can inform the code that certain triangles are hidden from each other and others are visible to each other Parameters LABS The label of the source triangles FLAG 1 All triangles with label LAB1 are visible from all triangles with label LABS 2 All triangles with labels in the range LAB1 to LAB2 inclusive are visible from all triangles with label LABS 3 All triangles with label LAB1 are hidden from all triang
251. her 1 for wire segments or 34 determined from 2 32 for surface elements triangles and quadrangles Other values and other binary additions are not allowed Similar to the AutoCAD import quadrangles are automatically subdivided along the shorter diagonal into two triangular patches Again scaling is allowed Since wires don t have a radius in the model files the radius is specified with a pre ceding IP card Likewise the elements don t have labels and the label as specified at the last LA card before the IN card is used If there is no LA card the label defaults to zero Obviously since no labels are present in the Concept files a label selective import is not supported As for the CAD models dielectric triangles or metallic triangles which form the surface of a dielectric are created by preceding the IN card with the appropriate ME card The Concept files for wires is as follows number_of_wires x_start y_start z_start x_end y_end z_end number_of_wires times where the first integer specifies the number of wires followed by the coordinates of the start and end point of each wire The file is completely free format the values are just separated by white space The surface file is number_of_nodes number_of_patches xyz number_of_nodes times pl p2 p3 p4 number_of_patches times again using free format The values x y and z specify the node coordinates and p1 p2 p3 and p4 specify the corner nodes of the trian
252. hout including the local machine The fek input file must then be located on the first PC in the list and the out file is created on this PC both in the exactly same directory as the project directory on the local machine It is the user s responsibility to transfer the files between the local machine and the first machine in the list if these are not the same WinFEKO does not do this EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 13 When the user clicks OK on this window the hosts are saved to a file machines feko in the directory specified by the environment variable FEKO_USER_HOME The format of this file is the same as that of the default machines file created during installation It is not required to run the configuration but one may do so at any time to change the host list 3 5 4 2 Execute Once a proper machines feko file has been created FEKO is executed by selecting Solver Parallel version Execute WinFEKO searches for a machines file in the order FEKO_USER_HOME machines feko FEKO_USER_HOME machines FEKO_HOME AmpiXshareWmachines feko FEKO_HOME mpi share machines and uses the first file that exists It then calls RUNFEKO with the np x option to start the parallel version In this case x is calculated as the sum of the processes listed for the hosts in the machines file 3 5 5 Results menu This menu is used to load and display data obtained from the output
253. hown in figures 2 10 b and c These two problems can be solved using respectively electric and magnetic symmetry about the plane z 0 Each of these problems require only half the number of unknowns required for case a Superposition of the problems b and c which must unfortunately be done manually as FEKO cannot do it automatically at the moment yields the original problem The solution of each of the sub problems requires only half of the storage space required for case a For very large problems the solution time is dominated by the time required to solve the system of linear equations In this case the two sub problems each requires only one eight of the time required for case a EM Software amp Systems S A Pty Ltd December 2002 GENERAL COMMENTS 2 11 2 5 Dielectric solids There are six possible ways to model dielectrics two of these apply to arbitrary bodies e In the surface current method the surface is subdivided into triangular surface ele ments Basis functions are applied to these elements for the equivalent electric and equivalent magnetic surface currents Boundary conditions result through the use of equivalent sources The geometry is entered through the use of the ME card section 8 2 24 By using the ME card it can be specified whether the triangular elements are to be used for metallic surfaces or dielectric surfaces It is possible to use triangles and segments defined as metals within the die
254. ic body on the lid of the cylinder which is also the basis of the dielectric cone e Dielectric triangles forming the surface of the dielectric body the boundary between medium 1 the inner dielectric region and medium 0 the free space outer region on the top surface of the cone Since there is symmetry in two planes only a quarter of the structure is generated The geometry part of the input file is given below detailed comments being included with the ME card Definition of the variables and discretisation parameters lambda 1 0 wavelength a 0 3 lambda radius of cylinder th 0 6 lambda height of cylinder and cone epsr 2 relative dielectric constant side_l lambda sqrt epsr 6 IP side_1 Definition of the points DP A 0 0 0 DP AO 0 0 th DP AU 0 0 h DP C tta 0 0 DP CU tta 0 h Generate a quarter of the geometry First generate the metallic surfaces that are found in free space medium 0 Either leave out the ME card or include it like this ME 0 Basis of the cylinders KR AU A CU 90 side_1 Surface of the cylinders ZY AU A CU 90 side_1 December 2002 FEKO User s Manual 8 66 ME KK kk ok ME KR DESCRIPTION OF THE GEOMETRY CARDS Now the outer surface of the cone is generated as the outer surface of a dielectric body where the normal vector points from medium 1 to medium O as shown in the drawing dl 0 A AD C 90
255. ich continuous data is available are listed under Parameter at the top The other selections depend on the selected parameter For this example we select Z sol 1 source 1 which refers to the input impedance of the first source encountered in the first solution block The solution counter is incre mented each time a new solution is encountered for example when adding a skin effect December 2002 FEKO User s Manual 13 4 THE PROGRAM ADAPTFEKO and requesting a new solution In this example there is only one source and one solution The remaining parameters are selected as required before creating the graph The Modify button may be used to change the last set of lines added to the graph as long as the active graph has not changed This is mostly used to change the number of frequency increments Note that the results are continuous this selection specifies only the number of sample points used for the graphical representation The resulting input impedance is given in figure 13 2 Note the grey marks at the bottom which give the sample frequencies used by ADAPTFEKO These marks can be switched of from the Bottom axis panel which may be accessed from the Main graph settings panel Figure 13 3 shows results over a small frequency band where a solution obtained with linear stepping is added to the same graph Note how close the results match even though ADAPTFEKO used only a single sample in this region This example was taken from the pape
256. id in this direction S3 Name of a point in the direction y 0 in elliptical coordinates The distance of the two points S and S3 determines half of the axis of the ellipsoid in this direction S4 Name of a point in the direction of the third coordinate i e the dis tance S4 S1 S3 S and S2 S must be perpendicular The distance of the two points S and S4 determines half of the axis of the ellipsoid in this direction Ri Begin angle J in degrees of the ellipsoid R Begin angle pa in degrees of the ellipsoid Rs End angle ve in degrees of the ellipsoid R End angle pe in degrees of the ellipsoid Rs Maximum edge length of the triangles along the curved edge in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used Note that the angles Y and y are defined in an elliptical rather than in a spherical coordinate system For a Cartesian coordinate system with origin S1 the x axis in direction of S3 the y axis in the direction of S4 and the z axis in the direction of S2 a point on the surface of the ellipsoid is given as x a sinY cos p r y Osind sing z c cos where the lengths a b and c are the lengths of the ellipsoid s three half axes For example the length a is the distance between the points S3 and Si The normal vector of the generated triangles always points outwards The algorithm used for the segmentation can fail if the ratio o
257. ied impedance refers to the metallic ground plane and a transformation must be done to get the correct load impedance at the triangle Ri Real part of the load impedance in 2 Ra Imaginary part of the load impedance in Q R3 Only if l2 1 the x coordinate of the load position in m Ra Only if f2 1 the y coordinate of the load position in m Rs Only if f2 1 the z coordinate of the load position in m Reg Only if 3 1 the radius of the load pin in m The values R3 Ra Rs and Rg is scaled by the SF card if SKALFLAG 1 The implementation is such that if an L4 card is processed any existing load on that triangle is replaced For example the card sequence L4 5 50 0 L4 5 20 0 will add a 20 Q load to the triangle with label 5 and not a 70 Q load It must also be noted that if the L4 card is used in conjunction with an A4 card im pressed current source the load impedance of the L4 card is placed parallel to the input impedance of the A4 source it has no effect if it is in series with the current source i e the resulting input admittance is the sum of input admittance without the L4 load and the admittance added by the L4 card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 75 9 2 29 LD Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 LAB RS LS cs INT INT INT INT INT STR STR STR STR STR REAL REAL REAL REAL REAL REAL REAL REAL With this card it is possible t
258. ig wip File containing the magnetic field strengths Contains both the position and the complex components of the magnetic field strength vectors This file is only generated on request by a DA card section 9 2 21 Data file containing the field distribution calculated by FEKO for cou pling with CableMod Log file created by OPTFEKO File in which the matrix elements of the linear equation system are stored only generated on request of a PS card section 9 2 36 FEMAP model file NASTRAN geometry file which can be imported with the IN card Geometrical data file which is exported by the program FEMAP Input file for the program OPTFEKO Paging files for the array elements used with sequential and parallel out of core solution To avoid the 2 GByte file size limit or on parallel systems with a distributed file system several files may be used These are distinguished by adding numbers to the filename File containing the surface currents and the currents in the segments Data is in the form of position and the complex components of the current density vectors This file is only generated on request by a DA card section 9 2 21 Output file from FEKO in which the results of all the calculations and messages can be found Input file for PREFEKO For the UTD an optional ray file can be requested allowing the ray paths to be visualised in WinFEKO File containing the right hand side vector in the system of linear equa tions Fi
259. ignment is Ey Ey Ey Ey and 3 E but in a spherical coordinate system one would have Ei Ey Eo Ep he Ey The value of Neomp which must be 1 2 or 3 determines which component of the Ne il field strength value shall be used for the normalisation The last three parameters f fo and fg on the line following the keyword are weighting factors which are discussed below when describing the aim function EM Software amp Systems S A Pty Ltd December 2002 THE OPTIMISER OPTFEKO 10 13 Let Ex i be the kth with k 1 2 3 component of the electric field strength in the ith block with i 1 Ng and the jth line in this block with j 1 Ng then we define normalised field strength values as Ek ij where Enorm is the Neompth component of the Nnormth field strength value that has been selected for the normalisation this is a complex quantity with amplitude and phase The aim function Z for the optimisation is then defined as 1 Ng Ns Z Ne Ne 2 2 A lerig fe lezij eagle fa lesag esil The values enim are the desired field values and they must be specified in a tabular format in the opt file after the first two lines with the keywords and the parameters There are in total Ng Ns lines with all the field values and each line has 6 columns with magnitude and phase in degree of the 3 normalised field strength components 1 x e2 jk and 3 the inner loop is the one over j i e the
260. ile on a local PC before submitting it to a parallel computer e ENV value This has the same effect as starting FEKO with the environ ment variable ENV set to value More than one e argu ment is allowed December 2002 FEKO User s Manual 7 2 THE PROGRAM FEKO 7 2 2 Running the parallel version The parallel version is started with on Windows it can also be configured and started from WinFEKO see section 3 5 4 runfeko example_08 np x where the parameter x following np gives the required number of processes In addition to the arguments listed in section 7 2 1 the parallel version accepts the following optional parameters np x Start the parallel FEKO version with x processes machines file machname The file machname is the machines file with the node names and the number of CPUs see below mpi options All options following this if another xxx options parameters is used all arguments before the second xxx options parameter are passed to the MPI launcher e g mpirun The number of processes to start on each available host is specified in a so called machines file with the general syntax Hostname Number of processes using a new line for each host For example if the user has two hosts with names host1 and host2 this is the output of the UNIX command hostname and 4 and 8 processors respectively the machines file will be host1 4 host2 8 With this machines file the example with 6 processes
261. in the computation time For example for an SK card the whole matrix has to be recalculated while an Ax card only redefines the right hand side of the matrix A summary of the dependencies is given in the table below Action For the cards recalculates matrix elements BO CO DI FR GF LD LE LP LS LZ SK TL recalculates the right hand side Ax BO DI FR GF resolves the matrix equation CG There are also other dependencies If the matrix elements are recomputed then the matrix equation has to be solved again The actual calculation is started by the FE FF OS and SP cards All other cards are read and the data stored When solving for a number of frequencies parameter NFREQ in the FR card all the control cards following the FR card until the next FR card or EN card are read into a buffer For each frequency all these cards are read and processed The computation time can be reduced significantly by using the cards in the correct order If for example a structure needs to be investigated at two frequencies and with two different excitations then the control cards can be organised in either of the following ways FR FR card for the two frequencies Ax first excitation Ax second excitation EN end of the input file or FR FR card for the two frequencies Ax first excitation FR FR card for the two frequencies Ax second excitation EN end of the input file EM Software amp Systems S A Pty Ltd December 2002 DESCR
262. ing an existing line The card editor can also edit existing lines The line at the current cursor position may be edited either by pressing lt F1 gt selecting Edit Edit line from the main menu or by right clicking at any position in the editor and selecting Edit line at cursor from the pop up menu Note that right clicking does not change the cursor position When the selection or highlighted part in the editor spans more than one line the line or lines cannot be edited This also applies for multi line cards such as the GF card in this case the cursor must be on the first line of the card and all lines will be edited simultaneously EditFEKO processes each card as if it does not contain errors For some of the fields where the user may select a number of options the card editor s display will default to a common value if the input field is invalid Thus it is advisable to close the card editor with OK even when it was used just to check the validity of the line If the user type for example PS and then press lt F1 gt EditFEKO may treat it either as a new card with default options or an existing card with all options blank zero Setting all options to zero does not always make sense and EditFEKO thus treat this case as a new card and use the normal defaults If the user wants to have a card with all option zero he should type the card name followed by a space before pressing lt F1 gt When editing existing lines t
263. ing factor such that the total radiated power the sum of the power radiated by all the individual sources is Po parameter PWPOWER Mismatch is not considered 2 All voltage sources are assumed to have an input impedance Zi as specified by the parameters Ra real part and Rs imaginary part The currents are scaled such that the total power supplied by the voltage sources equals P parameter PWPOWER as discussed below The mismatch losses in the source impedance Z reduce the antenna gain 3 All the antennas are assumed to be fed by transmission lines with a complex characteristic impedance Zz as spec ified by the parameters R real part and R3 imaginary part If there is a mismatch between Zz and the antenna input impedance Z some of the incident power will be re flected back to the source With PWFLAG 3 all currents are scaled such that the total incident power is Po param eter PWPOWER as discussed below The reflected power reduces the antenna gain PWNOCPL 0 If multiple impressed sources elementary dipoles A5 A6 impressed current elements AI AV etc are present the mutual coupling of all these sources as well as the coupling of the sources with other structures such as ground BO card UTD surfaces or MoM elements is taken into account when determining the source power This is also the default if the PW card is not present December 2002 FEKO User s Manual 9 86 DESCRIPTION OF THE CONTROL CARDS 1 This mu
264. ints 1 x 1 obtained in a previous run Then the previous run must have used keepfiles 13 3 The pre input file The pre file is created as for linear or multiplicative stepping The only requirement is that only one FR card is used and that this card requests a continuous frequency band The variable adaptfreq is defined automatically at the start of the single frequency input files and this variable may be used to allow for example adaptive meshing One should not directly assign this variable inside the pre file as this will overwrite the value specified by ADAPTFEKO at the top of the file If one needs this variable for example to run PREFEKO during model setup when using adaptive meshing one may use the DEFINED function 11if not defined adaptfreq then adaptfreq 250 0E6 lendif December 2002 FEKO User s Manual 13 2 THE PROGRAM ADAPTFEKO 13 4 ADAPTFEKO example As an example we will consider the input impedance of a simple forked dipole shown in figure 13 1 The input file forked_dipole pre is as follows this file is located in the examples utils adaptfeko subdirectory of the FEKO installation xk Forked dipole antenna Full MoM solution with adaptive frequency sampling Frequency for the discretisation lam c0 3 0e8 ok IP kk DP DP DP DP LA BL BL SY LA BL xk EG xk A1 FR Segmentation parameters Define some points P1 P2
265. ion where the coupling between the MoM and the Fock regions is considered 1 The coupling between the MoM and Fock regions is neglected so that there is no feedback by which the Fock currents may influence the current distribution in the MoM region This option which is particularly applicable when the MoM and Fock regions are not in close proximity should result in a considerable reduction in com putational effort and storage space The radius of the cylinder or sphere does not have to be defined It is determined by the distance of the metallic triangles with the label S2 to the axis or centre The cylinder Fock currents can also be applied to cones KK card approximated by a staircase construction of cylinders and sections of a torus that resembles a cylinder TO card Although the FO card is strictly only applicable to spherical and cylindrical surfaces it is often a good approximation on conical and toroidal surfaces EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 29 8 2 15 HE Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ri Ra R3 R4 R5 TR ae any INL NT REAL REAL REAL REAL REAL REAL REAL REAL With this card a helical coil consisting of wire segments can be created A sketch is shown in figure 8 20 Figure 8 20 Sketch illustrating the use of the HE card Parameters S Name of the begin point of the coil s axis S2 Name of the end point of
266. ipole moment depends on EII5 and is given by Led m gt X plA jw The power radiated by the dipole in a free space environment is given by _ Bo Zro IA P 127 FEKO however considers the properties of the medium in which the dipole is located as well as the coupling of the dipole with surrounding structures or other sources for December 2002 FEKO User s Manual 9 18 DESCRIPTION OF THE CONTROL CARDS example other magnetic dipoles in an aperture approximation see the AP card when calculating the power radiated by the Hertzian dipole Even though the two formulations EII5 0 electric ring current and EII5 1 magnetic dipole result in the same near and far fields if the dipole moment m is the same the radiated potentials are different The electric ring current model gives rise to a magnetic vector potential A while the magnetic dipole model results in an electric vector potential F as wella magnetic scalar potential Y EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 19 9 2 10 A7 Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 NFU ULA EIR1 EIR2 EIR3 EIR4 EIR5 IE REAL REAL REAL REAL REAL REAL REAL REAL This card is used to specify a voltage source on an edge between two triangles or at a connection edge between a single triangle and a PEC ground plane or UTD plate As it is substantially simpler it is strongly recommended to use the AE card rather than the A7 card
267. irection of propag BETAOX 1 6736E 10 BETAOY 0 0000E 00 BETAOZ 4 0800E 01 Field strength in V m EOX 1 00000E 00 ARG EOX 0 00 Phase in deg EOY 0 00000E 00 ARG EOY 0 00 EOZ 4 1021E 10 ARG EOZ 0 00 The vector B whose components are given is the vector which points in the direction of propagation The vector Eg represents the direction of the electric field 14 3 Currents and charges After solving the matrix equation the currents are extracted if extraction has not been suppressed by the parameter PS4 in the PS card A surface current that flows perpendicularly to the edge belongs to each edge The coefficients appear in the table SURFACE CURRENT DENSITY ON TRIANGLES in A m no node real part imag part magn phase 1 6 9254E 04 1 0356E 03 1 2458E 03 123 77 2 0 0000E 00 0 0000E 00 0 0000E 00 00 3 1 0281E 03 1 4961E 03 1 8153E 03 55 50 4 1 0036E 03 1 3894E 03 1 7140E 03 125 84 5 7 0292E 05 1 7210E 05 7 2369E 05 13 76 When examining segments each node is assigned a current CURRENTS IN SEGMENTS in A no node real part imag part magn phase 1 3 3953E 03 1 7374E 03 3 8140E 03 27 10 2 6 2056E 03 3 0587E 03 6 9185E 03 26 24 3 8 4702E 03 3 9922E 03 9 3638E 03 25 24 December 2002 FEKO User s Manual 14 8 DESCRIPTION OF THE OUTPUT FILE OF FEKO For connection points between segments and triangles the current of each basis function is given CURRENTS AT CONNECTION POINTS in A
268. is FALSE Examples illustrating some of the points above are as follows lif fa gt 5 then l endif or 1 a 5 gt 21 and a lt 100 11if 3 at 5 gt x 2 and not 1 then llelse EM Software amp Systems S A Pty Ltd December 2002 THE PREPROCESSOR PREFEKO 6 9 aif sin x 10 gt 0 5 then else endif l lendif 6 6 Symbolic node names When defining or using node names simple variable names of the form A i are allowed The algorithm is that if a hash sign is found in a node point name this hash sign and everything that follows is interpreted as a variable string evaluated and rounded to the nearest integer Thus if we have k 15 and use or define a point P k then this is equivalent to using P15 as point name The length of the node name string before and after expansion is still limited to 5 characters For instance it would now be possible to define the points P1 to P20 inside a loop for k 1 to 20 DP P kK Inext 6 7 PRINT and EXIT commands PREFEKO also supports the command exit to stop execution and the print com mand to print strings enclosed in double quotes and floating point numbers The print command command accepts multiple arguments separated by commas For example Iprint 2 b 2 b llif fa lt 2 b then print The value of a is too small Ha 1 exit llendif exiting now will print a warning and exit if the variab
269. isible line with the lowest number 5 3 4 10 Sqr Line A This allows taking the square of a graph This item can be called with one or two lines visible on the graph the operation is performed on the visible line with the lowest number 5 3 5 Tools menu Unwrap phase The Unwrap phase item is toggled between checked and unchecked When this item is checked the plots on the graph are considered to be phase plots and are unwrapped where they jump through 360 degrees 5 3 6 Window menu The Window menu controls the display and arrangement of the multiple graph windows in the main GraphFEKO display 5 3 6 1 Cascade This option arranges the graph windows stacked behind each other with the top name bars of all graph window visible 5 3 6 2 Tile This option arranges the graph windows in horizontal tiles 5 3 6 3 Arrange icons This option only applies to the icons of minimised graphs It arranges the icons associated with all minimised graph windows next to each other at the bottom left of the main GraphFEKO display EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM GRAPHFEKO 5 21 5 3 6 4 Minimise all This option minimises all graph windows 5 3 6 5 List of windows You can select a graph window by clicking on the graph window or by selecting the name of the graph file associated with a graph window from the graph files listed under the Windows menu option 5 3 7 Help menu 5 3 7 1 User s man
270. isplay 3 25 solution information 3 23 sources 9 5 Hertzian electric dipole 9 16 impressed line current 9 20 9 25 9 39 incident plane wave 9 8 magnetic dipole 9 17 magnetic ring current 9 13 microstrip line 9 23 patch feed pin 9 14 radiation patterns 9 34 voltage on a node 9 12 voltage on a segment 9 11 voltage on an edge 9 19 9 23 SP card 9 93 sphere 8 60 dielectric magnetic 8 18 spiral 8 29 square root in GraphFEKO 5 20 square in GraphFEKO 5 20 stripline feeding 9 23 loading 9 74 SU card 8 90 substrate 9 67 subtract lines in GraphFEKO 5 19 superuser mode in EditFEKO 4 2 in FEKO 8 90 surface currents distribution 9 81 with WinFEKO 3 5 surface elements see elements surface triangles see elements SY card 8 91 symbolic variables 6 1 symmetry 2 7 8 91 electric 2 7 geometric 2 7 magnetic 2 8 templates 3 6 for GraphFEKO 5 3 TG card 8 92 thin dielectric sheet 9 89 third party CAD running from WinFEKO 3 10 setting options for 3 32 TIMEFEKO 11 1 TL card 9 94 TO card 8 95 toolbars visibility 3 33 tools in WinFEKO 3 29 find element 3 4 toroidal segment 8 95 TP card 8 98 transformation 8 92 model 3 30 of point 8 98 translation 8 92 8 98 transmission line 9 94 transmission line coupling 9 20 9 46 triangles see elements unwrap phase 5 20 UT card 8 99 UTD 8 99 cylinder 8 101 polygon 8 84 UZ card 8 101 variables environment 2 15 in point na
271. itation by a magnetic ring current TEM frill on a segment Parameters ANFL 0 New excitation replaces all previous excitations 1 Additional excitation add to previous excitations ULA The label of the segment on which the TEM frill is placed If there are more than one segments with the same label the excitation is placed on the last segment Alternatively one may set ULA 1 then the feed segment is determined by its Cartesian coordinates EIR5 y EIR6 and z EIR7 EIR1 Absolute value of the voltage Uo in V EIR2 Phase of the voltage Uy in degrees EIR3 Radius of the inner conductor of the coaxial feed EIR4 Radius of the outer conductor of the coaxial feed EIR5 Only if ULA 1 the x coordinate of the feed position in m EIR6 Only if ULA 1 the y coordinate of the feed position in m EIR7 Only if ULA 1 the z coordinate of the feed position in m The values EIR5 EIR6 and EIR7 are scaled by the SF card if SKALFLAG 1 EIR8 The port impedance if this excitation is used in an S parameter calculation If this field is empty or 0 the value specified at the SP card is used This value is ignored if no SP card is used The vector of the excitation points in the direction from the start point to the end point of the segment i e in the direction in which the segment was created in the BL card The excitation is not as in the previously mentioned card an impressed electric field strength but it is a magnetic ring current
272. ith this card the Green s function may be selected Currently the following Green s functions are supported e Homogeneous Medium GFFLAG 0 This is the standard free space Green s function similar to when the GF card is not used The medium is normally free space but different parameters can be set with the EG card The parameters as set by the EG card is retained only when all the real parameters R to Rs of the GF card is empty or zero If any of the medium parameters below is set all the EG card values are overridden Those parameters that are not specified will then default to the values given here Parameters GFFLAG 0 Green s function for free space is used R Relative permittivity of the homogeneous medium if this field is empty r 1 is used Ra Relative permeability ur of the homogeneous medium if this field is empty uu 1 is used Rs Conductivity o in of the homogeneous medium Ra Magnetic loss factor tan 9 of the homogeneous medium the complex permeability is then given by u Hokr 1 j tand tan is set to zero if this field is empty Rs Electric loss factor tan of the homogeneous medium This is an alternative way to specify the conductivity a the two loss terms are related by tan e but have different frequency behaviour If both R3 and Rs are empty or zero tan is set to zero December 2002 FEKO User s Manual 9 68 DESCRIPTION OF THE CONTROL CARD
273. itted CDICKE Thickness of the outer layer in m it is scaled by the SF card For wires this is the radius of the coating less the radius p of the wire core CMUER Relative permeability ur of the outer layer CEPSR Relative permittivity e of the outer layer CSIGMA Conductivity o in s of the outer layer CRHO Wire radius o of the metallic wire without layers in m it is scaled by the SF card This overrides the values speci fied with the IP card This field is only applicable to wire coatings CTANDMUE Magnetic loss factor tan of the outer layer the complex permeability is then given by 4 Hokr 1 jtand CTANDEPS Electric loss factor tan 6 of the outer layer an alternative way to specify the conductivity the two loss terms are related by tand 27 and have different frequency behaviour December 2002 FEKO User s Manual 9 48 DESCRIPTION OF THE CONTROL CARDS For DOCOVR 3 or 4 there follow N 1 more lines with only the parameters CDICKE CMUER CEPSR CSIGMA CTANDMUE and CTANDEPS of the remaining layers Note that the layers are symmetric on both sides of the conductor and the last input line is closest to the conductor 0 KONM O CDICKE CDICKE Figure 9 17 Double sided coating of surface elements Note that the coating should be thin relative to the triangle dimentions It is enlarged here for visualisation With DOCOVR the user can chose between two different formulations for the trea
274. iven above See also the files pattern opt and pattern pre in the subdirectory examples utils optfeko under the FEKO installation directory Radar cross section RCS With this aim function the RCS o can be minimised or maximised either the average value or the minimum maximum value over a range of angles and over a range of frequencies blocks This aim function is defined by the keyword RCS it is the same in German and English The parameters M Ng and Ns are specified on the next line Ng specifies the number of blocks that will be considered and Ng the number of values read from each block for example the number of angles for which the calculation is to be made The parameter M EM Software amp Systems S A Pty Ltd December 2002 THE OPTIMISER OPTFEKO 10 9 has the following meaning 2 Maximise the minimum RCS i 1 Maximise the average RCS 1 Minimise the average RCS 2 Minimise the maximum RCS The average value or minimal maximal value of the RCS is determined from the Ng x Ng calculated values In the case of the average value the aim function Z is given by the following relation Ng Ns Z sign M SLL i l j l The inclusion of sign M ensures that minimising the aim function gives the appropriate result Example RCS 1 3 90 Impedance reflection factor With this aim function the input reflection factor of the antenna can be minimised The optimisation can be broad band by examining a number
275. ividual components of the electric and the magnetic field strength This is the total value of the field i e the sum of the incident wave and the scattered field If the electric field inside dielectric cuboids is determined then the value for the SAR specific absorption rate and the cuboid number are also given X m 0 050 0 050 0 050 0 050 LOCATION Y m 0 050 0 050 0 050 0 050 VALUES OF THE ELECTRIC FIELD STRENGTH in V m inside the dielectric cuboids EX Z m magn 0 050 5 776E 00 0 150 2 192E 01 0 250 2 584E 01 0 350 2 625E 01 EY phase magn 59 89 1 259E 01 33 75 4 114E 00 31 18 3 420E 00 22 29 8 499E 00 EM Software amp Systems S A Pty Ltd EZ phase magn phase 177 82 1 415E 02 125 12 122 93 1 640E 02 130 45 19 21 1 679E 02 137 51 24 72 1 551E 02 144 87 SAR cuboid no in W kg 0 000E 00 0 000E 00 0 000E 00 0 000E 00 PUNE December 2002 DESCRIPTION OF THE OUTPUT FILE OF FEKO 14 13 14 6 Far fields If the far field is calculated the following block in this form is displayed VALUES OF THE SCATTERED ELECTRIC FIELD STRENGTH IN THE FAR FIELD in V Factor e j BETA R R not considered LOCATION ETHETA EPHI directivity in dB THETA PHI magn phase magn phase vert horiz total 90 00 0 00 1 235E 00 168 98 0 000E 00 0 00 7 1722 999 9999 7 1722 90 00 2 00 1 233E 00 168 90 0 000E 00 0 00 7 1583 999 9999 7 1583 90 00 4 00 1 227E 00 168 65 0 000E 00 0 00 7 1166 999 9999 7 1166
276. j To use the CableMod interface this module must be activated if required please contact EMSS December 2002 FEKO User s Manual 9 6 DESCRIPTION OF THE CONTROL CARDS Al card Voltage source on a segment A2 card Voltage source on a node between segments J E i A3 card TEM frill on a segment fe magnetic current loop U Figure 9 1 Possible ways to realise a voltage source on a wire segment A4 card Vertical pin approximation dielectric substrate A7 card Voltage gap on an edge VVVVVY E 1 AE card Voltage gap along edges VVVVYVY Figure 9 2 Possible ways to realise a voltage source in connection with triangles EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 7 More than one excitation is also allowed Thus one may for example generate an ellip tically polarised plane wave by super imposing two out of phase linearly polarised plane waves with different amplitudes It is also possible to feed an antenna with two differ ent voltage sources For this purpose the parameter ANFL is available in each Ax card This parameter indicates whether the current excitation is additional ANFL 1 or not ANFL 0 When ANFL 0 only the current excitation will be used and the excitations prior to the current one will be erased For the excitations Al A2 A3 A4 and A7 it is possible to select the feed element through the la
277. ject under consideration is too large in terms of wavelengths to solve with the MoM but too small to apply only the asymptotic UTD approximation with high accu racy With the hybrid MoM PO or hybrid MoM UTD techniques critical regions of the structure can be considered using the MoM and the remaining regions usually larger flat or curved metallic surfaces using the PO approximation or UTD Only time domain harmonic sources are supported in the current version and conse quently calculation is done in the frequency domain FEKO uses the e t time conven tion Different sources are available including an incident plane wave various voltage gap formulations between wire segments and a magnetic ring current TEM Frill with which a coaxial feed can be modelled WinFEKO is the main user interface module and is used to control the solution of a problem The geometry is defined in terms of high level commands in an input file pre which also sets the solution parameters The customised text editor EditFEKO assists the user in creating and editing the input file The preprocessor mesher PREFEKO processes this file and prepares the input file fek for the program FEKO which is the actual field calculation code PREFEKO enables the user to create complex geometries with a single command for example coils consisting of wire segments or flat cylindrical or spherical plates consisting of triangles The geometry can also be created in the 3D C
278. l conductivity without any losses EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 93 9 2 39 SP Card Ry A IE REAL REAL REAL REAL REAL REAL REAL REAL This card is used to calculate the S parameters for the active sources Parameters R The reference impedance This is used for all sources for which no impedance value is specified when defining the source If this field is empty it defaults to 50 Q The N ports must be defined before using the SP card They are identified simply by defining excitation cards Currently only A1 A2 A3 A4 and AE sources are supported Al A2 and A3 sources must be selected by label not with position and unique labels must be used i e no other segments or triangles may have a label which is used for a port If the amplitude of any port is set to zero it will be used as a receive port or sink but not as a source For example if only S21 and S11 are required for a two port network one may set the amplitude of the source defining port 2 to exactly zero Then Si2 and S22 are not calculated in some cases this may save considerable computation time The load impedance for each of the port sources can be specified at the source itself If no such impedance was specified the R value specified with the SP card will be used if this value is not specified it defaults to 50 Q This load impedance will be added automatically to each port It must b
279. l reflection gives a node whose aim function is not smaller than the value of the Simplex node with the second highest value of the aim function Expan sion stretches the Simplex beyond the range of a normal reflection It only takes place when the value of the aim function on the normally reflected node is smaller than that on the node with the previously smallest value of the aim function the output Simplex Example SIMPLEX_METHOD 0 15 0 5 0 001 0 001 1 0 0 5 2 0 EM Software 4 Systems S A Pty Ltd December 2002 THE OPTIMISER OPTFEKO 10 5 Conjugate gradient method The keyword for this optimisation method is KONJUGIERTE_GRADIENTEN_VERFAHREN or CONJUGATE_GRADIENT_METHOD A full description of the conjugate gradient variants im plemented in OPTFEKO Fletcher Reeves or Polak Ribiere and their necessary param eters can be obtained from the file example opt Example CONJUGATE_GRADIENT_METHOD 2 0 1 1 0E 6 1 0E 4 1 0E 3 1 618034 100 0 1 0 2 O 0 01 Quasi Newton method The keyword used for this method is QUASI_NEWTON_VERFAHREN or QUASI_NEWTON_METHOD A full description of the Quasi Newton methods Davidon Fletcher Powell DFP and Broyden Fletcher Goldfarb Shanno BFGS can by found in the file example opt Example QUASI_NEWTON_METHOD 2 0 1 1 0E 15 2 5E10 1 0E 4 1 0 100 0 1 0E 7 1 0E 4 2 0 01 For more information on the optimisation parameters please consult the file example opt in the doc optfeko subdirectory un
280. l sources that are active when the SP card is processed are considered as ports LOAD IMPEDANCES AT PORTS port impedance in Ohm 1 5 00000E 01 2 1 00000E 02 3 5 00000E 01 Then the S parameters are listed for each source as shown below Note that sources whose amplitude are set to exactly zero are only used as sink ports i e they are not excited and no such block is created All the ports are loaded and FEKO therefore also writes this information to the output file The second data line below gives S21 or the coupling to port 2 when port 1 is excited In the second block here under the first line gives S13 or the coupling into port 1 when port 3 is excited SCATTERING PARAMETERS ports magnitude phase sink source real part imag part linear in dB in deg S 1 1 6 14622E 02 3 53596E 01 3 58898E 01 8 90 80 14 S 2 1 3 61992E 03 5 42992E 03 6 52594E 03 43 71 56 31 S 3 1 1 46490E 03 1 73598E 02 1 74215E 02 35 18 94 82 December 2002 FEKO User s Manual 14 16 SCATTERING PARAMETERS ports sink source real part imag part line S 1 3 1 31791E 03 1 74114E 02 1 74612 S 2 3 9 17744E 01 1 08299E 01 9 24112 S 3 3 3 49405E 01 4 49374E 02 3 52282 14 8 Computation time The final section in the output file gives an overview of the computation in a tabular format SUMMARY OF REQUIRED TIMES IN SEC CPU time Reading and constructing the geometry 0 031 Checking the geometry 0 000 Initialisation of the Greens function 0 000 Calcul
281. lanar aperture from a text file see below Read magnetic field values for a planar aperture from a text file see below Read both electric and magnetic field values for a pla nar aperture from files in efe and hfe format respectively H MT ow Q M A q HI al u MT aD Read both electric and magnetic field values for a planar aperture from text files see below Lt TT NI Electric field values for a planar aperture follow in the pre input file see below u MT 00 Magnetic field values for a planar aperture follow in the pre input file see below U p o Both electric and magnetic field values for a planar aper ture follow in the pre input file see below 15 16 19 The same as 5 6 9 but for a cylindri cal aperture rather than a planar one Note that in this case both the electric and mag netic fields are required 25 26 29 The same as 5 6 9 but for a spheri cal aperture rather than a planar one Note that in this case both the electric and mag netic fields are required December 2002 FEKO User s Manual 9 28 DESCRIPTION OF THE CONTROL CARDS The sign of the parameter TYPE is used to determine if dipoles should lie on the edges of the aperture or not see figures 9 10 to 9 13 For positive values of TYPE the dipoles lie on the edges for negative values the dipoles lie half an increment
282. layers Ri The thickness d of the nt layer in m if an SF card is present this is scaled independent of the value of SKALFLAG R The conductivity in 5 of the n layer Rs The loss factor tan tan 27 of the n layer R The relative dielectric constant of the n layer for Ig 5 I3 The number of layers If this field is empty 0 or 1 there is just one layer R The relative permeability ur Note that all layers must have the same permeability R3 x component of the vector used to define the principle direction see R below Ra y component of the vector Rs z component of the vector Rz Magnetic loss factor tan d the complex permeability is then given by u Hokr 1 jtand Note that all layers must have the same permeability now follow J3 lines with the parameters of the layers this approximation is such that it is independent of the order of the layers Ri The thickness d of this layer in m if an SF card is present this is scaled independent of the value of SKALFLAG R The angle a in degrees by which the reference principle direction of this layer is rotated with respect of the projection of the vector onto the triangles R Conductivity o in g R Conductivity o in 5 of this layer in the orthogonal direction 5 The loss factor tand tand 27 of this layer in the principal of this layer in the principal direction direction Rj The relative dielectric constan
283. le After successful execution a file example fek is created This is the input file for FEKO The program PREFEKO allows a number of options which are mainly used for debug ging purposes Entering prefeko without arguments will give an overview of the syntax and supported options If for example the argument fek format x is specified PREFEKO creates a fek file using the x file format 6 3 Symbolic variables Instead of using numerical values in all the different cards it is possible to use predefined variables The name of a variable always consists of a sign followed by a string consist ing of the characters a z A Z 0 9 and the special character _ The following are valid variable names height a STARTINGFREQUENCY a_1 or P5_7f while the following are not valid a 1 or value2 1 There is no distinction between upper and lower case characters For example a and A is interpreted as the same variable Expressions and functions may be used when defining variables so that direct calculations can be carried out The variables have to be defined before they can be used in the respective cards It is possible to use expressions like 2 radius in the input fields subject to the maximum allowed length 10 characters for real values 5 characters for integer values For larger expressions additional variables have to be defined December 2002 FEKO User s Manual 6 2 THE PREPROCESSOR PREFEKO A variable is defined in the
284. le Below the edge numbers the area of the triangle is given in m2 Following this is an extract of the data for the edges between the triangle Whenever two triangles have two common vertices such an edge is generated DATA OF THE METALLIC EDGES with MoM triangle no points of tr no type length m media KORP KORM POIP POIM 1 1 5 3033E 01 0 1 1 2 1 1 2 1 3 7500E 01 0 1 1 33 2 3 3 1 3 7500E 01 0 i 1 65 3 2 information on symmetry yz XZ xy status 0 49 93 unknown 0 2 94 0 0 50 3 unknown December 2002 FEKO User s Manual 14 2 DESCRIPTION OF THE OUTPUT FILE OF FEKO Each edge is assigned a consecutive number which appears in the first column The length of the edge is given in the second column and the medium in which the edge is found appears in the third column On an edge there are exactly two triangles In the columns KORP and KORM the numbers of these two triangles are given and the positive current direction is from the triangle KORP to the triangle KORM In the column POIP the number of the corner point of the triangle KORP which is opposite to the edge is given The same applies to the column POIM The next four columns contain information concerning the symmetry In the column yz the number of the edge appears corresponding to the plane x 0 yz plane of symmetry A positive sign indicates that the currents are symmetric and a negative sign indicates that the currents are anti symmetric If there is a 0 present in thi
285. le The Near fields panel in GraphFEKO is activated The various frequencies at which the FEKO solution has been obtained are displayed in the Frequency box The near field data blocks one per FE card available at that frequency are displayed in the Block no list Under Scale the user can select a linear or logarithmic scale to use a logarithmic scale the plot parameter must remain larger than 0 or he can plot the quantity in dB If any of the quantities selected have negative values and either Log or dB scaling has been selected then a warning will be given and the graph will be plotted on a linear scale In addition the user can specify if a Polar amplitude versus angle or Line graph standard rectangular 2D plot of the quantity value as a function of the independent variable should be created Plotting the near field data as a function of the coordinates Ifa single frequency is selected it is possible to plot the near field as a function of any of the principle coordinates Select a Block no and an Independent variable against which the data must be plotted on the Plot options panel The associated coordinate in the Near field blocks then changes colour Select the correct value for the other two components in the lists on the Near field blocks panel In certain coordinate systems or for separately specified points some coordinates is dependent on each other In this case more than one coordinate will change if the user change th
286. le a is smaller than two times variable b December 2002 FEKO User s Manual 6 10 THE PREPROCESSOR PREFEKO 6 8 Copyright to Voronoi The preprocessor PREFEKO uses part of the program voronoi to execute a Delaunay tri ang ulation for some of the geometric cards The parts of this program may be used freely and the required Copyright declaration is supplied in the accompanying documentation The Copyright declaration follows XK XA kA A XA A XA XX KF The author of this software is Steven Fortune Copyright c 1994 by AT amp T Bell Laboratories Permission to use copy modify and distribute this software for any purpose without fee is hereby granted provided that this entire notice is included in all copies of any software which is or includes a copy or modification of this software and in all copies of the supporting documentation for such software THIS SOFTWARE IS BEING PROVIDED AS IS WITHOUT ANY EXPRESS OR IMPLIED WARRANTY IN PARTICULAR NEITHER THE AUTHORS NOR AT amp T MAKE ANY REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM FEKO 7 1 7 The program FEKO 7 1 Introduction The program FEKO does the actual field calculation Input and output are done using files The program indicates on screen how far the calculation has progressed 7 2 Runni
287. le for coupling of FEKO with CableMod It is usually created by CableMod but can also be created by FEKO if requested with the OS card field calculation along lines Touchstone format S parameter file as created by the DA card The n refers to the number of ports see section 9 2 21 File in which the currents the coefficients of the basis functions are stored for reuse generated on request from a PS card section 9 2 36 Input file for the program TIMEFEKO When multiple reflections are used with the PO formulation FEKO determines which basis functions have line of sight visibility Since this calculation may require significant run time this information can be saved to a vis file for reuse Figure created and saved with GraphFEKO WinFEKO project file The files efe hfe ffe and os are redundant All the information in these files is also available in the out file The format of these redundant files lends itself more readily to further processing December 2002 FEKO User s Manual 2 4 GENERAL COMMENTS 2 3 Entering the geometry Conducting surfaces are subdivided into triangles and wires into segments For di electrics there are a number of possibilities see the discussion Dielectric Solids in section 2 5 Using the surface current method the surface of the dielectric solid is also sub divided into triangles whereas with the volume current method the solid is subdivided into cuboids Given belo
288. lection coefficient method is used see the BO card section 9 2 17 e Spheres consisting of one or more dielectric layers A special Green s function is available see the GF card section 9 2 27 December 2002 FEKO User s Manual 2 12 GENERAL COMMENTS e Planar multilayer substrate with or without a perfect conducting ground plane A special Green s function is available see the GF card section 9 2 27 e Thin dielectric sheets The volume equivalence principle is applied and the resulting equivalent currents approximated by a surface current see the SK card section 9 2 38 The entered structures e g metallic wires and surfaces do not necessarily have to be embedded in free space The EG card section 8 2 12 can be used to specify the material parameters of the surrounding medium 2 6 Dynamic memory management 2 6 1 Setting maxalloc for out of core solutions FEKO has the ability to manage the required memory dynamically i e the memory required for the geometry data and matrix equations is determined and allocated at run time When FEKO tries to allocate memory it cannot determine the difference between RAM and virtual memory system swap space Due to the access times required for virtual memory and the random nature of memory access the in core solution is very inefficient when used in this way FEKO also has an out of core solution which uses the data on disk in a much more efficient way The out of core technique is
289. lectric The ME card specifies the respective dielectric media on the two sides of the di electric and uses the normal vector of the triangles to distinguish the two sides Therefore the normal vectors should be checked with WinFEKO Example_04 Ezx amples Guide shows a simple dielectric sphere A more complex geometry where a dielectric body is in contact with a conducting body is described in example_23 Further details can be found there The material properties are assigned through the use of the DI card section 9 2 22 e In the volume current method the volume is subdivided into cuboids through the use of a QU card section 8 2 31 Each element can be assigned a different material property Inside the element the polarisation current is assumed unknown NOTE If both Er A Er environment and pr A Hr environment at any position then two elements have to be assigned to that position one for the dielectric property and one for the magnetic property In example_09 Examples Guide a dielectric cube is analysed with the volume current method The difference in the two methods is listed below Surface Current Method Volume Current Method the surface has to be discretised the volume has to be discretised homogeneous solids only inhomogeneous solids possible Apart from these two general formulations there are a number of special solutions for dielectric bodies e Dielectric hal space e g ground surface In this case the ref
290. les from the user 10 2 The pre input file The first required file is the normal pre input file for PREFEKO where the symbolic optimisation parameters are used to define the variables that must be optimised During optimisation these parameters are varied by OPTFEKO It repeatedly generates new pre files in which the optimisation parameters are assigned The user can assign values to these variables for example in order to run PREFEKO and view the geometry using the DEFINED function An example is given in section 10 5 10 3 The opt input file The optimisation method its parameters and the aim of the optimisation are stored in a second file with a opt extension This file consists of three or four sections e Assignment of optimisation parameters minimum and maximum values e Optional assignment of the penalty function e Set optimisation parameters e g step size final value e Set the aim function with the required parameters In the opt file blank and or comment lines starting with are allowed between the sections but they are not allowed to appear in the sections themselves The parameters December 2002 FEKO User s Manual 10 2 THE OPTIMISER OPTFEKO are space delimited i e they are separated by spaces and can be placed in any column but they must be entered in the correct order The keywords used in the opt file exist in both German and English for example RASTERSUCHE and GRID_SEARCH Both version
291. les with label LABS 4 Al triangles with labels in the range LAB1 to LAB2 inclusive are hidden from all triangles with label LABS LAB1 The label of the visible or hidden triangles LAB2 The end of the label range if FLAG is 2 or 4 Note that visibility is reciprocal i e if all triangles with label LAB1 are visible from all triangles with label LABS all triangles with label LABS are visible from all triangles with label LAB1 as well The labels must be specified in ascending order i e LABS lt LAB1 lt LAB2 LABS may never decrease in consecutive VS cards In addition for different VS cards with the same value of LABS LAB1 of any card must be larger than LAB1 in case of a single layer or LAB2 in case of a range of layers of the previous card See the example below Basis functions cannot illuminate each other if all the triangles they are attached to lie in the same plane The VS card should only be used if the user can specify the visibility beyond any doubt If no information is specified for a specific combination of labels triangles full ray tracing will be executed December 2002 FEKO User s Manual 8 104 DESCRIPTION OF THE GEOMETRY CARDS Example of VS card usage Consider the structure shown in figure 8 58 consisting of four flat plates and a cylindrical section The two plates lying at 45 degrees to the coordinate system labelled 1 and 3 are half as wide as the plates with labels 0 and 2 Thus some tri
292. llowing the AR card in the pre file the format is described below Iz This parameter is only relevant for Jz 1 or Ig 2 and gives the line number of the first line to read from the input file If the data must be read from the beginning of the file 3 should be set equal to 1 This parameter is used when the ffe file contains more than one pattern For example if the file contains the pattern at various frequencies the correct pattern can be selected by setting the appropriate value of I3 for each frequency I The number of Y angles in the pattern I The number of angles in the pattern Ri The values of the complex field strengths EP F and EP F are read from the data file I2 1 or Iz 2 or the pre input file Iz 3 The parameter R is used to scale the amplitude of the field strength by a constant value Ra The parameter R specifies a constant additional phase for the field strength values EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 35 R3 x coordinate of the source point i e the position where the antenna is placed in m this value is affected by the scale factor of the SF card if SKALFLAG 1 Ra y coordinate similar to R3 above Rs z coordinate similar to R3 above Reg The angle a in degrees with which the imported pattern is rotated around the x axis Rz The angle a of the rotation around the y axis similar to Re Rg The angle a of the rotation
293. lot real and or imaginary parts or the magnitude or the phase and plot the current on the selected segment More than one segment can be selected for current plotting but only one incident direction can be selected Induced current as a function of incident angle If the FEKO solution contains more than one plane wave incident angle at one or more frequencies the Inc field block will contain a list of items when the associated frequency is selected Each item represents a different incident angle in the order they are written to the output file The current I gt induced in a segment can be plotted as a function of incident angle To do this select a single frequency and multiple incident directions In this case the current can be plotted for only one segment at a time The user can of course plot the current on different segments one after the other using the Add to graph button 5 3 2 7 Current extraction This allows the extraction of segment currents irrespective of the type of excitation It is exactly analogous to the previous section except that the Inc field block is replaced by the Excitation block which lists the different excitations it is incremented each time a solution is done for a different set of sources The Labels list is included for future use and is not active at present As before the New graph button plots the frequency or incident field dependent data for the quantities selected on a new graph the Add to gra
294. lowed between and next but not before the All instructions and input cards between for and next are evaluated repeatedly inside the loop e Several loops can be nested as shown in the example below A more complicated example illustrating some of the points above is as follows end 3 sin 4 for x1 sqrt 5 2 3 to 2 end step end 10 for x2 1 23 to 2 x1 this is the inner loop December 2002 FEKO User s Manual 6 8 THE PREPROCESSOR PREFEKO x3 x1 x2 DP sedi more commands next Inext 6 5 IF ELSE ENDIF constructs This construct is used to allow different control cards under different conditions The syntax requirements of IF ELSE ENDIF constructs are e The characters must be located in the first two columns of the line This is followed by an arbitrary number of spaces the expression to evaluate evaluated and the keyword then it is not case sensitive THEN or Then are also accepted e The block is terminated by a line of the form endif again spaces are allowed between and endif but not before the e An optional line of the form else again the must be in the first two columns and spaces are allowed before the keyword which is not case sensitive e All instructions and input cards between if and endif or else if it is present are processed if the expression is TRUE If it is present all lines between else and endif are processed if the expression
295. lways offer the flexibility which one may require for example to change the material parameters inside the loop Another example would be the use of a loop to create a complex geometry For completely general loops PREFEKO allows the construct for var start to end step delta Inext EM Software amp Systems S A Pty Ltd December 2002 THE PREPROCESSOR PREFEKO 6 7 where a simple example would be Loop for the relative permittivity for epsr_r 1 to 5 step 0 5 Set material parameters GF 0 eps_r 1 Compute fields etc FE End of loop Inext The syntax requirements of FOR NEXT loops are e The characters must be located in the first two columns of the line This is followed by a number of optional spaces and the keyword for it is not case sensitive so also FOR or For are accepted e The keyword for is followed by the name of the loop variable starting with The variable name is terminated by a space or the sign e Next follows an expression for the initial value of the loop a constant variable or formula see the example below e This is followed by the keyword to and the terminating value of the loop variable again a constant variable or formula e The default increment of the loop variable is 1 but it can be changed by using the keyword step followed from an expression Negative increments are allowed e The loop is terminated by a line of the form next spaces are al
296. mains 0 Is For 15 0 the scaling factor Ry is applied to all three coordinates of each point For I5 lt gt 0 scaling is done by interpreting I5 as a 3 bit number with possible values from 1 to 7 If the first bit value 1 is set then the scaling factor Ry does not apply to the x coordinate of the point If the second bit value 2 is set the y coordinate is not scaled and if the third bit value 4 is set then the z coordinate is not scaled If J 7 no scaling is done and then one must set Ry 1 R Angle of rotation a around the x axis in degrees R2 Angle of rotation a around the y axis in degrees R3 Angle of rotation a around the z axis in degrees Ra Translation A in the x direction All three translation distances are affected by the scaling factor set with the SF card Rs Translation A in the y direction Reg Translation A in the z direction Rz The scaling factor y with which the point is scaled after rotation and translation if the parameter Ry is not specified it defaults to y 1 If a point is rotated around more than one axis with a single card it is rotated first by an angle a around z axis then by a around the y axis and finally by a around the x axis A more detailed description of the transformation can be found in the description of the TG card section 8 2 35 In an exception to the rule that all geometry cards must appear before the EG card this card as well as the DP card can be used
297. maximum number of edges between triangles that may be excited with the AE card maxanr The maximum number of sources maxapo The size of the memory block that is used to save the coefficients in the physical optics approximation For maxapo 0 the necessary amount will be dynamically allocated maxarang The maximum number of Y or y angles used with the AR card ex citation by a point source with a specified radiation pattern maxarpat The maximum number of radiation pattern excitations AR card allowed simultaneously maxbsobnr To accelerate the ray path search with PO the area under consid eration is divided into boxes Information pertaining to which box contains which object must be stored A field of size maxbsobnr is used in this case December 2002 FEKO User s Manual 2 14 maxckant maxcolayer maxdels maxdrnv maxfepkts maxfoge maxgfmsia maxhacards maxkanr maxknonr maxl4cards maxlab maxlecards maxleedges maxlengz maxmedia maxndr maxnka maxnkapo maxnk1l maxnkno maxnlayer EM Software amp Systems S A Pty Ltd GENERAL COMMENTS The maximum number of cut edges per cut in LFFEKO The maximum number of layers on a CO card using DOCOVR 3 or 4 The maximum number of star basis functions that are deleted in LFFEKO For each surface one star function has to be deleted The maximum number of triangle elements that can be connected to a segment at an attachment poin
298. may only plot the magnitude The New graph button plots the frequency dependent data for the quantities selected on anew graph The Add to graph button sends data for the selected quantities to the active graph window The Cancel button closes the Antenna parameters panel and activates the Main graph settings panel 5 3 2 4 S parameters SP card When this item is selected GraphFEKO loads the S parameters as calculated by FEKO on request of the SP card see section 9 2 39 from the selected output file and opens the Antenna S parameters panel The various frequencies at which the FEKO solution has been obtained are displayed in the Frequency box The Card nr field lists the SP cards for each frequency Click to highlight a frequency or select a range of frequencies by clicking and dragging the mouse If a range of frequencies that does not all have the same number of SP cards is selected the frequencies with a different number of cards than the first is automatically unselected If more than one SP card is used for each frequency the user can also plot the result as a function of the card number In this case only one frequency may be selected The is useful to plot the S parameters as a function of other parameters in the pre file for example the value of a terminating resistance Under Scale the user can select a linear or logarithmic scale to use a logarithmic scale the plot parameter must remain larger than 0 or he can plot the
299. mes 6 9 memory allocation 2 12 predefined 2 12 symbolic 6 1 version information 3 33 view angle settings 3 30 output file 3 13 visibility PO region 8 103 voltage source on a node 9 12 on a segment 9 11 on edge 9 19 9 23 VS card 8 103 warnings reporting in WinFEKO 3 32 wedge as PO border 8 55 WG card 8 106 WinFEKO 3 1 display excitation 3 29 display requested fields 3 28 display settings 3 1 3 23 file control 3 3 file menu 3 6 graphics card 3 2 hardware requirements 3 1 hot keys 3 2 ini file 3 2 loading results 3 13 memory requirements 3 1 preprocessing menu 3 10 running 3 2 solve menu 3 11 toolbars 3 3 tools 3 29 under MS Windows 3 1 wire curved 8 14 wire grid 8 106 wire segments see segments write access restrictions 3 32 Zin 3 13 5 6 zoom detail settings 3 30 previous zoom 3 5 speed buttons 3 5 to window 3 5 ZY card 8 108
300. metry There are three different types of symmetry They are described below 2 4 1 Geometric symmetry With this type of symmetry the geometry of the modelled solid or part of the solid is symmetric about one or more coordinate planes The interaction between any two basis functions must be the same as that between their symmetrical counterparts Everything which affects this must be symmetrical i e loading losses Green s functions etc The source however is not symmetric thus a symmetric current distribution does not exist This asymmetric current distribution leads to asymmetric electric and magnetic fields The body of a truck with an antenna placed at the front left hand side will be used as an example In the input file half of the body is constructed either the left or right side The other half is then created with the SY command Finally the antenna is placed in the correct position on one side A rectangular metallic plate illuminated by an electromagnetic wave from a direction outside the principle planes is another example In this case a quarter of the plate is constructed and the rest is created using the SY card section 8 2 34 with geometric mirroring around two coordinate planes Geometric symmetry does not reduce the number of unknown coefficients in the current basis functions Therefore there is no reduction in memory usage There is however a reduction in computation time when the matrix elements are determin
301. mmetry there is a reduction in the computational time when determining the matrix elements The order of the matrix equation is reduced which leads to a further reduction in the computational time and reduces the amount of memory needed to determine the matrix elements 2 4 4 Example of the application of symmetry In figure 2 9 a dielectric sphere is shown with a linear polarised incident electromagnetic field The full description of the problem is given in example_04 in the Examples Guide Only the use of symmetry is described here The plane z 0 xy plane is a plane of geometric symmetry because the excitation does not have any symmetry in this plane The plane x 0 yz plane is a plane of electric symmetry because the electric field is perpendicular to this plane and the magnetic EM Software amp Systems S A Pty Ltd December 2002 GENERAL COMMENTS 2 9 Sa gt Figure 2 9 Dielectric sphere with incident field field has a tangential component only Similarly the electric field only has a tangential component in the y 0 plane and the magnetic field is perpendicular This is thus a plane of magnetic symmetry To indicate the reduction in time and resources through the use of symmetry a table is given below Type of Symmetry Number of Memory Solution Time Unknowns usage in seconds Symmetry not used 792 9 74 MByte 24 8 All 3 coordinate planes declared as 792 9 74 MByte 22 1 planes of geometric symme
302. mns of any line are separated by one or more spaces For example with a file containing Frequency in MHz Re load in Ohm Im load in Ohm 100 22 54 12 56 150 25 07 6 54 200 27 42 0 23 the frequency and loading can be imported directly from the file numfreq 3 Number of frequencies for i 1 to numfreq December 2002 FEKO User s Manual 6 4 THE PREPROCESSOR PREFEKO Define the frequency conversion from MHz to Hz freq 1 0e6 fileread datafile dat i 1 1 FR 1 0 freq xx Define the load Zr fileread datafile dat it1 2 Zi fileread datafile dat i 1 3 LZ 0 HZr Zi Computations next End of frequency loop In addition to these functions PREFEKO allows the use of logical operations It supports the function NOT which returns TRUE if the argument is FALSE and FALSE when the argument is TRUE and the delimiters gt lt gt lt lt gt AND and OR When boolean operations are applied to variables a value of 0 is taken as FALSE and everything else is interpreted as TRUE Similarly in the result of a logical operation FALSE is mapped to 0 and TRUE to 1 PREFEKO also supports a logical function DEFINED variable which returns TRUE if a the variable variable has been defined and FALSE if not This is useful in pre files where during OPTFEKO TIMEFEKO or ADAPTFEKO runs certain variables are inserted into the header of the file One can now process and view such
303. must appear in fixed column positions The editor EditFEKO was designed to simplify the process of generating pre files It is a basic text editor with customised functionality The main functionality is the specialised card editor for PREFEKO input cards It also has limited ability to handle opt OPTFEKO input files but currently uses a plain text editor for tim TIMEFEKO input files The program may be started from a command prompt by entering editfeko example pre where the optional parameter here example pre specifies the file to open If the pa rameter does not contain an extension the extension pre is added Also if such a file does not exist it will be created EditFEKO can also be opened from inside WinFEKO The interface consists of an editor area where more than one file may be opened In the standard PREFEKO mode the button panel which may be turned off or moved to either side of the editor area provides quick access to the card editors The status bar on the bottom of the window contains the line and column numbers indicates whether Insert or Overwrite mode is on and also gives an indication of the file modification status Note The editor is designed for a system with Small fonts selected in the Screen settings property of Windows If Large fonts is selected some items may be misaligned 4 1 General 4 1 1 File menu The File menu allows opening and closing files and is similar to stan
304. n registers all changes and the 3D pattern plots are updated and re displayed The OK button does exactly the same as the Apply button but also closes the 3D radiation patterns panel and activates the Main display options panel The Cancel button closes the 3D radiation patterns panel and activates the Main display options panel without applying any changes Select a frequency and far field block from the lists in the Data block selection group Select the Line Surface Colour or and Smooth options under Display options The Smooth option will only have an effect when the Surface option has also been selected Unselect the Surface option if the pattern data in the current block has been calculated at one theta or phi position only The available Far field quantity and Data component can also be selected To display the polarisation select Arial R or L R under Polariz options Axial R plots the axial ratio in shaded colours Dark blue represents 1 and red 1 L R plots Left Right or Linear polarisation direction Blue represents left Red represents Right and Green represents Linear Select Linear or dB scaling under the Scaling options Min minimum and Mar max imum slide bars and edit boxes are available to clip the limits of the data With Scale blob selected the 3D pattern itself will change when changing the Min and Maz settings With Scale blob unselected only the colour coding on the 3D pattern will change
305. n F The impedance is given by Zs Rs juLs a jw If CS 0 is selected it is interpreted as infinite capacitance i e in the case of the series combination it is zero The LS card may be combined with the LD LP LZ and the SK cards but only one LS card may be used per label If a second LS card is used it replaces the values entered by the first one This card has no significance for surface elements even when these are assigned the same label EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 79 9 2 33 LZ Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 Z LAB ZS ZS Real Imag INT NT R EA NT REAL REAL REAL REAL REAL REAL REAL REAL Here a complex impedance can be assigned to a segment Parameters LAB All segments with this label are assigned the impedance ZS ZS The complex value of the impedance in Q The value ZS is a constant it is not dependent on the frequency Frequency dependent impedances can be realised using the LS or the LP cards The LZ card may be combined with the LD LP LS and the SK cards but only one LZ card may be used per label If a second LZ card is used it replaces the values entered by the first one This card has no significance for surface elements even when these are assigned the same label December 2002 FEKO User s Manual 9 80 DESCRIPTION OF THE CONTROL CARDS 9 2 34 OF Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 OF
306. n a colour coded display averaged over the surface elements With Arrows selected the in colour checkbox and Arrow length edit box is activated The maximum arrow length can be set here by the user The default is obtained from the segment and or triangle side lengths of the model To return to the default value enter 0 in the Arrow length edit box and hit the Enter key Also under Current display select mag or instantaneous from the drop down list With mag selected Jz Jy Jz is plotted With instantaneous selected the real current vector is calculated as j t Re J edet December 2002 FEKO User s Manual 3 22 THE PROGRAM WINFEKO By default wt 0 is selected With instantaneous selected wt will become enabled and the required time instant value in degrees can be selected Select Linear or Log scaling under the Line currents A or Surface currents A m options Min minimum and Maz maximum slide bars and edit boxes are available to clip the limits of the surface and or line current data The surface and line currents as well as the model geometry can be made visible or invisible by selecting or unselecting the Currents and Geometry options in the Main display options panel Animation For arrow surface and line plots of currents animation is available First select and plot the required current display scaling etc With instantaneous selected under Current display the Animation button next to Surf
307. n is faster but uses more resources memory than gif animation Animated bmps can not be saved and can be viewed in WinFEKO only With Bmp animation the number of steps must be decided on before preparing the animation but the speed and continuous or not continuous settings can be modified while viewing the animation Under Settings select the number of animation steps Each step will represent one value of wt with wt varying between 0 and 360 degrees Note Each animation step records a bitmap picture of the screen in memory This process is memory intensive with each bitmap typically requiring between 1 and 2 MByte of RAM With gif animation each bitmap is converted to a gif reducing the required resources but increasing the time it takes to prepare the animation Select the animation speed and Continuous animation to display the animation steps repeatedly EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 21 Hit the Prepare animation button For large models and data sets the preparation of the animation pictures can take a while see progress bar To stop the process hit the Stop button The process would not stop immediately but only after the next screen capturing has taken place Note The render screen should be kept visible at all times while the animation is being prepared Don t open or activate other application that would partially or completely cover the render screen during this period On
308. n is only available if the appropriate near field calculations have been requested FE card Pointing vector S 3 Re E x H This is the Pointing vector The quantity is only available if both the electric and magnetic fields have been calculated with a single FE card in FEKO e SAR This is the Specific Absorption Rate calculated in a lossy dielectric as 1 ol El ARS SAR 5 with o the conductivity of the lossy dielectric E the magnitude of the electric field vector calculated by FEKO inside the dielectric and p the density of the dielectric material Select the More button top right of the Near fields panel to change the p density value The conductivity is read from the out file This option is only available if the appropriate near electric field calculations inside a dielectric have been requested see the FE card As before the New graph button writes the distance or frequency dependent data for the quantities selected to a new graph and the Add to graph button sends data for the selected quantities to the active graph window The Cancel button closes the Near fields panel and activates the Main graph settings panel December 2002 FEKO User s Manual 5 16 THE PROGRAM GRAPHFEKO 5 3 2 10 Adaptive frequency interpolation results ADAPTFEKO This option is only available if ADAPTFEKO is enabled in the licence and a afo file is available for the currently selected results file The afo file is created b
309. n the appropriate button on the button 3Certain options and functions are only accurate and or efficient for specific problems and require an intimate knowledge of the code EM Software amp Systems S A Pty Ltd December 2002 THE EDITOR EDITFEKO 4 3 panel or selecting from the Geometry cards and Control cards menus The buttons are grouped according to functionality namely e Definition of node points labels segmentation parameters and variables button e Cards to generate surfaces which will be meshed into triangles elements e Cards generating wire segments e Cards for generating dielectric magnetic volumes to be subdivided into cuboids or specification of dielectric regions e Cards used in connection with the PO formulation e Cards used in connection with the UTD formulation e Modifications to the geometry such as translation scaling and mirroring e The EG card signifying the end of the geometry All the cards whose buttons are above this button should be before it in the input file and those below must be after The IN card IF ELSE block cards and FOR NEXT loop cards appear next to the EG card as they can be used both above and below it e Cards dealing with finite medium properties and finite grounds e Cards dealing with loading of wire segments e Cards to specify the excitation type frequency and power of the excitation e Cards used to control which data is written to the output files e Cards to speci
310. n the rest For all files except SnP the data is in rows i e each new set of data is in a new row Complex numbers are given in the normal FORTRAN format Real Imaginary output e g 6 956E 03 1 034539E 07 December 2002 FEKO User s Manual 9 52 DESCRIPTION OF THE CONTROL CARDS 9 2 22 DI Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 D MED EPSR MUER SIGMA TAND TAND Re MUE EPS A IE REAL REAL REAL REAL REAL REAL REAL REAL Here the electric characteristics of the dielectric and magnetic bodies are entered when using the surface current method Parameters MED This gives the index of the medium as used at the ME card Zero indicates the surrounding free space medium and any other value the respective medium EPSR Relative dielectric constant e of the medium MED MUER Relative permeability ur of the medium MED SIGMA Conductivity o in of the medium MED TANDMUE Magnetic loss factor tan of the medium MED the complex permeability is then given by 4 our 1 jtand TANDEPS Electric loss factor tan of the medium MED this is alterna tive way to specify the conductivity da the two loss terms are related by tand and have different frequency be haviour Re The medium density in kg m This parameter is not used in FEKO but is written to the output file and used for SAR calculation during post processing e WErE0 Note that for backwards compatibility to older FEKO versions where
311. name efe hfe or text file from which the field data must be read The filename must be enclosed in double quotation marks and must be entered at or after column 81 in the pre file Filename When both electric and magnetic fields are read from file a second filename must be specified for the magnetic field data This follows also within double quotation marks at an arbi trary location after the first filename The aperture is based on the equivalence principle This states that the sources and scatterers inside a given volume can be removed and modelled by placing the equivalent currents e xH and M x E on the enclosing surface The vector n is a unit vector normal to the surface and points towards the exterior region The fields in this region are the same as the original fields while those in interior region are zero EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 29 Field values are read from the data files with a possible offset specified with NSTART or the pre input file and converted to equivalent electric magnetic fields and magnetic electric field dipoles at these points Note that all angles are read from the data but no distance values Thus for planar apertures the positions are calculated entirely from the specified points S1 S2 and S3 For cylindrical apertures Si and S2 specify the extents of the aperture along the local 2 direction and S3 sp
312. nce we have already specified the visibility between labels 0 and 1 we do not specify it again The fifth VS card then specifies that label 2 is completely visible from label 1 As for label 0 both labels 3 and 4 are hidden completely which completes the first six VS cards Next we look at label 2 As before we need not consider labels lower than 2 Also the label is hidden from itself as indicated by VS card number seven Next we state that label 3 is visible but we cannot specify anything about label 4 as only some of these triangles will be visible Similarly VS cards 9 and 10 states that label 3 is not visible to itself and fully visible to label 4 Finally we must consider the case for triangles with label 4 All visibility with layers 0 to 3 has been specified and may not be specified again Unlike the previous flat plates layer 4 is curved and some triangles may indeed illuminate other triangles with the same layer However not all other triangles will be illuminated this is only possible for a doubly concave surface such that we cannot specify any information for label 4 December 2002 FEKO User s Manual 8 106 DESCRIPTION OF THE GEOMETRY CARDS 8 2 41 WG Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ry Ra mo ae aes No NT REAL REAL REAL REAL REAL REAL REAL REAL With this card a wire grid in the shape of a parallelogram can be generated In figure 8 59 a sketch is shown S S Figure 8 59 Ske
313. nd type of vertex is a linker 0 VERTEX 8 LAYER_02 70 128 71 72 73 74 next keyword December 2002 FEKO User s Manual 8 42 DESCRIPTION OF THE GEOMETRY CARDS which defines a triangle or quadrangle by specifying the indices starting from 1 in the order the non linker vertices are specified of the vertices which form its corner points Vertices are defined as linkers by setting a value of 128 in the group code 70 field For linker vertices the coordinates are ignored Note that some old dxf versions do not contain linker vertices they cannot be imported Usually they do not contain mesh information The four integer numbers after the group codes 71 72 73 and 74 give the indices of corners of the triangle or quadrangle In the case of a triangle one of these is absent PREFEKO divides each quadrangle into two triangles along the shortest diagonal Note that the dxf specification does not require the group codes to be in any specific order However PREFEKO requires that the group codes 71 72 73 and 74 follow group code 70 If these extracts are taken from the file geometry dxf both the line meshed as segments and the two polyline triangles may be imported with the commands rad 0 001 seglen 1 IP rad seglen IN 4 geometry dxf 1 2 e FLAG 5 Read geometry from a NEC input file PREFEKO also supports importing wire geometry from NEC models Note that NEC models usually consist o
314. ng FEKO 7 2 1 Running the sequential version When FEKO is not executed from EditFEKO or WinFEKO it can be started in a DOS window on PC or a shell in UNIX by executing the command runfeko example_08 where example_08 pre must be an existing input file RUNFEKO executes PREFEKO if the fek file is missing or older than the pre file and then executes the appropriate FEKO solver sequential parallel or adaptive sampling It accepts the following optional parameters see also section 7 2 2 for additional options to launch and control the parallel version of the solver priority x The value x specifies the CPU usage priority of the FEKO run 0 idle 1 below normal 2 normal 3 above normal and 4 high If not specified the default is 2 This option might not be available for specific systems or specific FEKO versions then it is just ignored prefeko options All options following this if one is used up to the next xxx options are passed to PREFEKO feko options All options following this if one is used up to the next xxx options are passed to FEKO adaptfeko options All options following this if one is used up to the next xxx options are passed to ADAPTFEKO The optional command line parameters for FEKO specified after feko options are check only If this option is used FEKO processes and checks the geome try but does not start a solution This is useful to test an input f
315. ng PIM 18 TFQMR using PIM 19 Parallel LU decomposition with ScaLAPACK solution in main memory or with out of core ScaLAPACK solution with the matrix stored on hard disk This is the default option for parallel solutions and normally the user need not change it 20 QMR using QMRPACK MAXIT The maximum number of iterations for the iterative techniques December 2002 FEKO User s Manual 9 44 DESCRIPTION OF THE CONTROL CARDS PCFLAG Determines the type of preconditioning 0 No preconditioning is used 1 Scaling the matrix A so that the elements on the main diagonal are all normalised to one 2 Scaling the matrix A A so that the elements on the main diagonal are all normalised to one 4 Block Jacobi preconditioning with block size BLOCKNB for a PIM method The inverses of the preconditioner are calculated and applied during every iteration step For performance reasons PCFLAG 64 is recommended 8 Block Jacobi preconditioning of the matrix with block size BLOCKNB before beginning the iteration with a PIM method i e before executing any matrix multiplication For performance reasons PCFLAG 64 is recommended 16 Symmetrisation of the matrix in FEKO a Galerkin tech nique is used with different integration algorithms so that the resulting matrix is non symmetrical 32 Neumann polynomial preconditioning 64 Block Jacobi preconditioning where for each block a LU decomposition is computed in advance and
316. ng electrical contact with the end point EIR1 Amplitude J in A of the current at the start point 7 EIR2 Phase of the current at the start point in degrees December 2002 FEKO User s Manual 9 40 EIR3 EIR4 EIR5 EIR12 EIR2_2 EIR32 EIR42 EIR52 EIR62 The following restrictions apply when using the impressed current elements making elec DESCRIPTION OF THE CONTROL CARDS x coordinate of the start point 7 in m Note that all the coordinate values are scaled by the SF card if SKALFLAG 1 y coordinate of the start point 7 in m z coordinate of the start point 7 in m Amplitude J2 in A of the current at the end point Fa Phase of the current at the end point in degrees For ULA 0 x coordinate of the end point 72 in m see comment for EIR1 For ULA 0 y coordinate of the end point 7 in m For ULA 0 z coordinate of the end point 7 in m This parameter is optional If specified and different from zero this value gives a finite wire radius for the impressed current element FEKO then assumes that the current is uniformly distributed on the wire surface and uses the exact wire integral If the parameter EIR6_2 is not specified the current filament approximation is used This value is scaled by the SF card if SKALFLAG 1 trical contact with conducting surfaces e All the restrictions given in the discussion of the AI card also apply in this case e The start point of the impressed current segment may b
317. ngs for the line series available on the active graph The details will not be discussed here Most if not all of the options are self explanatory Support on any of the settings can be obtained from feko_support emss co za 5 3 3 3 Copy graph Copy the current graph to the Windows clipboard such that it can be pasted into another application The graph is copied in the enhanced Windows metafile format EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM GRAPHFEKO 5 19 5 3 4 Tools menu gt Line arithmetics The Line arithmetics item under the Tools menu allows simple arithmetics using two lines on the current graph If the current graph contains more lines they must be deleted or made invisible see the discussion of the Main graph settings in section 5 3 3 1 The two lines must have the same x values they are added on a point by point basis without checking the x axis values The result is added as an additional line on the current graph 5 3 4 1 Add two lines This gives the sum of the two lines on the graph 5 3 4 2 Subtract two lines This has three sub items Line A refers to the visible line with the lowest number and line B to the other line One can plot the second line subtracted from the first the first from the second or the absolute value of the difference 5 3 4 3 Multiply two lines This gives the product of the two lines on the graph 5 3 4 4 Re Im gt Amp This takes the magnitude of th
318. ngth to give the normalised radiation pattern For example if one computes the full horizontal cut of the radiation pattern for an antenna to be optimised vertical polarisation and at the FF card in FEKO computes the field December 2002 FEKO User s Manual 10 8 THE OPTIMISER OPTFEKO for Y 90 and y 10 20 30 360 p 0 has been excluded since it is equal to p 360 the values would be M 1 vertical pol Ng 1 and Ng 36 If one wants to design for example a sector radiator which gives zero radiation in the angular ranges y 0 90 and y 270 360 and maximum radiation in the angular range y 150 210 and a linear increase decrease in the angular ranges p 90 150 and y 210 270 the definition in the opt file would be RADIATION_PATTERN 1 1 9 15 21 27 36 36 6 eo OrRrrF OO F TO O This can be used for example to determine the amplitude and phase of four impressed Hertzian dipoles to get the best possible approximation of the pattern discussed above The pre file will then contain something like 1 0 3 lambda A5 0 ttal p1 1 0 0 0 A5 a a2 p2 0 1 0 0 A5 1 tta3 p3 1 0 0 0 A5 1 a4 p4 0 1 0 0 Compute the horizontal radiation pattern 10 deg stepping FF 1 1 36 0 90 0 10 and the opt file will contain a variable section giving ranges for these eight variables an optimisation method and the RADIATION_PATTERN block g
319. ns Fock regions polygonal plates UTD cylinders and tetrahedral elements are processed The label criterion of specified by the parameters Jz and 3 remains in effect 1 Only metallic triangles Fock regions and wedges and edges in PO regions that satisfy the label criterion of zg and I3 are processed 2 Only metallic segments that satisfy the label criterion of Iz and I are processed 4 All dielectric triangles are processed Labels are ignored and selection with Jj and 13 is not possible This is only supported for compatibility reasons and the use 5 32 is preferred EM Software 4 Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS Ri Ra R3 Ra Rs Re R7 8 16 32 64 128 256 512 All dielectric and magnetic cuboids are processed Labels are ignored and selection with I2 and f3 is not possible This is only supported for compatibility reasons and the use 5 64 is preferred All polygonal plates are processed Labels are ignored and se lection with Jz and Jz is not possible This is only supported for compatibility reasons and the use 5 128 is preferred Only dielectric triangles that satisfy the label criterion of I gt and I are processed Only dielectric and magnetic cuboids that satisfy the label criterion of f3 and Is are processed Only polygonal plates that satisfy the label criterion of Iz and I3 are processed Only UTD cylinders that satisfy the label crite
320. nsmission line and the start of another All transmission lines ending at one wire are connected in parallel Any load impedance defined over the transmission line port segments with the LZ LS LP LD CO or SK cards are placed in series with the port parallel admittances can be defined directly at the TL card If a voltage source of type Al or A3 is applied at one of the port segments then this voltage source is assumed to be across the port i e feeding the transmission line directly with an impressed voltage Any other sources are in series with the port December 2002 FEKO User s Manual 9 96 DESCRIPTION OF THE CONTROL CARDS FEKO automatically determines the type of the transmission line network 1 no impressed voltage source at both ports 2 impressed voltage source at port 1 3 impressed voltage source at port 2 4 impressed voltage source at both ports Both wire segments for port 1 and port 2 should be located in the same medium so that the propagation constant of this medium can be taken for the transmission line If the segments are in different media then the medium of the segment at port 1 is used Note that the propagation constant and thus also the propagation loss of the transmission line is the same as that of the medium surrounding port 1 unless an additional loss factor is specified with Rg If this is free space the transmission line will be lossless For transmission lines with a propagation constant that is higher than
321. nter file or clipboard the following options are also available e Grayscale A completely new model with Grayscale colouring is printed e Reverse The background is white instead of black and all white pixels or lines are drawn in black e Project Info Information relating to the current project will also be printed When printing to a printer the Frame option is automatically enforced if this option is selected Not available for clipboard printing e Frame Draws a frame around the model Not available for clipboard printing EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 9 On printing to the clipboard select either the Bitmap or Metafile option Metafile clip board printing is vector based and the image created would not necessary appear exactly as on the rendering screen in WinFEKO Click the Preview button to get a preview and to enable the Print button The model as it will be printed to a file or printer is displayed All rendering of the model is now disabled To change the model size position or any other setting click the Cancel button and manipulate the image Select Print and Preview again to return to the previewing of the model Click the Print button to send the selected model display to a printer file or clipboard When printing to a file a Print To File dialogue box is opened Select a file name and directory path Click the Save as type drop down list to selected one o
322. nternal EMF electromagnetic force of the impressed voltage source is in the opposite direction In certain special cases there may be only one triangle connected to the edge If the edge lies in the plane of a polygonal UTD plate or a PEC ground plane specified with a GF or BO card the excitation is placed on the appropriate basis function connecting the triangle to the plate plane The positive feed direction is then towards the edge December 2002 FEKO User s Manual 9 20 DESCRIPTION OF THE CONTROL CARDS 9 2 11 AC Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 Filename INT INT INT INT INT STR STR STR STR STR This card inputs data from a rsd file containing the geometry of a transmission line and the current distribution along this line for one or more frequencies Such a rsd file is created for example by the transmission line simulation program CableMod or with the OS card in FEKO The excitation is due to the electromagnetic fields radiated by these line currents the CM card allows the treatment of electromagnetic fields coupling into lines Parameters I 0 New excitation replaces all previous excitations 1 Additional excitation add to previous excitations If the imported rsd file contains currents for several frequen cies I must be set to 0 as the AC card then results in a fre quency loop and currents with different frequencies cannot be superimposed If it is not 0 PREFEKO
323. o account when the second FE card is run Thus the first frequency pass is finished At the next frequency pass the cards FE SK and FE are read again but the losses from the SK card are still active from the first pass The SK card is thus useless and the two FE cards calculate the same things twice The correct input order is FR FR card for multiple frequencies SK skin effect switched off FE calculation of the near fields SK skin effect switched on FE calculation of the near fields EN end of the input file Then the four cards SK FE SK and FE are calculated for all the frequencies December 2002 FEKO User s Manual 9 4 DESCRIPTION OF THE CONTROL CARDS 9 2 Detailed description of the control cards 9 2 1 Card 12 6 10 15 20 25 30 40 50 60 70 80 90 100 110 xx lo lan ler lso REAL REAL REAL REAL REAL REAL REAL REAL The comment lines discussed in section 8 2 1 can also be used after the EG card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 5 9 2 2 Ax Cards This card defines the type of excitation as well as other parameters regarding the excita tion The following possibilities are available Card Type of Excitation AO A linear polarised plane wave incident on the structure A1 Excitation by means of a voltage gap on a segment i e impressed electric field strength along a segment A2 Excitation by means of a voltage gap at a node i e between two segments
324. o specify a distributed resistive capacitive or inductive loading or even a series combination of these values for a segment Parameters LAB All segments with this label are subjected to distributed loading RS The distributed resistance in 2 LS The distributed inductance in E CS The distributed capacitance in E The combined impedance of the segment with length is then Zs A A el a jwC It should be noted that CS 0 is treated as infinite capacitance such that the C term may be neglected The LD card may be combined with the LP LS LZ and the SK cards but only one LD card may be used per label If a second LD card is used it replaces the values entered by the first one This card has no significance for surface elements even when these are assigned the same label December 2002 FEKO User s Manual 9 76 DESCRIPTION OF THE CONTROL CARDS 9 2 30 LE Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 I Ig I3 R x eva lernlerglaynlerg REAL REAL REAL REAL REAL REAL REAL REAL With the LE card an edge between surface triangles can be loaded with an impedance Z R jX see the AE card for the excitation of such an edge as shown in figure 9 26 As shown in the figure the edge can consist of several single edges each of which should be common to triangles that have one of only two labels One of these labels must be unique i e only one triangle at each single edge should have this label See the AE card section 9
325. o the axis is determined by the value specified with the IP card The parameter Ra determines the maximum edge length along the curved side such that a better representation of the curve may be obtained if required If the geometry representation is accurate enough R may be left empty and the value specified by the IP card will be used also along the curved edges The direction of the normal vector is obtained through the parameter S4 First example of ZY card usage Using the following commands the cylindrical section shown in figure 8 62 is generated IP DP DP DP ZY EG EN e awe O O OGOGO wooo a ONO O oOo Figure 8 62 Example for the ZY card December 2002 FEKO User s Manual 8 110 DESCRIPTION OF THE GEOMETRY CARDS Second example of ZY card usage An elliptical cylinder as shown in figure 8 63 is generated with the following commands Example for an elliptical cylinder General parameters a 1 5 first half axis of the elliptical cylinder Hb 2 5 second half axis of the elliptical cylinder h 4 height of the cylinder Segmentation kanl 0 4 IP ffkanl Define points DP A 0 0 0 DP B 0 0 h 2 DP C a 0 0 Define the geometry ZY A B C 90 ttkanl b a End EG EN Figure 8 63 Example of an elliptical cylinder EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 1 9 Description of the con
326. ob December 2002 FEKO User s Manual 8 10 DESCRIPTION OF THE GEOMETRY CARDS define some points DP DP DP DP DP DP DP DP DP DP DP A AGA dauauy 0 0 len 2 0 len 2 0 pl_len 2 0 pl_len 2 0 0 0 tot_len 20 tot_len 20 tot_len 20 pl_len 2 0 0 0 wid 2 wid 2 0 0 pl_wid 2 pl_wid 2 0 pl_wid 2 tot_wid 2 tot_wid 2 tot_wid 2 create the geometry edge_x 1 0 edge_globti tedge_ap 2 x for diagonals BQ A B E F edge_ap edge_x edge_x BQ B C D E edge_ap edge_x edge_x BP E D G H BP J E H I BP K E J create the full plate with symmetry SY 1 1 0 1 end of geometry EG EN Figure 8 8 Example of a BQ card with an inhomogeneous segmentation EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 11 8 2 5 BT Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Ry Ra R3 T ae ey NT NT REAL REAL REAL REAL REAL REAL REAL REAL Using this card three points are joined to form a triangle This triangle will then be subdivided further into triangular elements In figure 8 9 a sketch is shown S S Figure 8 9 Sketch illustrating the use of the BT card Parameters S Name of the first point of the triangle S2 Name of the second point of the triangle S3 Name of the third point of the tri
327. of another wire where the connection points do not coincide see figure 2 2 or connecting surfaces that have different segmentation along the common edge see figure 2 4 Such errors are detected EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 25 if the parameter NOCHECK is not set to 1 The error detection routine should always be used However if the same geometry is to be used a number of times the error detection can be disabled by setting NOCHECK 1 If the surrounding medium is not vacuum one can set the material parameters with the EG card as shown above Alternatively the parameters of the surrounding medium can be set with the GF card which offers greater flexibility For example the GF card can be used to set the material parameters as an arbitrary function of frequency inside a frequency loop which is not possible with the EG card December 2002 FEKO User s Manual 8 26 DESCRIPTION OF THE GEOMETRY CARDS 8 2 13 EL Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ri R2 R3 R4 R5 INT INT INT INT STR STRI STRISTR R REAL REAL REAL REAL REAL REAL REAL REAL With this card a section of an ellipsoid can be generated see figure 8 18 Parameters S Name of the point at the centre of the ellipsoid S2 Name of a point in the direction Y 0 in elliptical coordinates The distance of the two points S and S2 determines half the axis of the ellipso
328. of frequencies at the same time One can also optimise the reflection factor of multiple different ports simultaneously The average reflection factor is minimised with the option to limit values that have a sufficiently good match to avoid that these are optimised further rather than focusing on the optimisation of other impedance values with a worse match The assignment of the aim function in the opt file is started by the word IMPEDANZ or IMPEDANCE In the next row the parameters Zre Zim and N are specified Zyre is the real part and Zim the imaginary part of the target impedance Zsou N is the number of blocks in the output file of FEKO from which the impedance Z is read Example IMPEDANCE 50 O 1 The aim function is defined as 1 y ee Zi Zsoli Zit Zso Zsolt l December 2002 FEKO User s Manual 10 10 THE OPTIMISER OPTFEKO As a modification one can specify an optional forth parameter in the line following the keyword IMPEDANZ or IMPEDANCE for example IMPEDANCE 50 O 1 15 0 The fourth parameter is the minimum reflection coefficient TB in dB and if specified min the modified algorithm to compute the aim function Z is as follows For all impedance values i 1 N define the reflection coefficient Li Zsoll Py 20 Li Zsoll rdB min and then truncate to Imin 10720 ficient in the summation i e the corresponding linear desired reflection coef 1 N Z N A ER m
329. oil requires shorter segments than those used for straight wires Thus the maximum segment length specified by the IP card can be overridden along the arc by setting Ro The windings are generated between the two points S and Sa that lie on the axis The radius of the coil is defined by the distance between the points S and S3 For elliptical cross sections this is the length of one half axis and the other one is Rs times this length Example of HE card usage The two coils shown in figure 8 21 are created with the following commands IP 0 02 0 5 DP Ai 0 0 0 0 0 0 DP Bi 0 0 0 0 1 0 DP Ci 0 3 0 0 0 0 HE Ail Bi Ci 0 4 5 0 2 DP 42 0 0 1 0 0 0 DP B2 0 0 1 0 1 0 DP C2 0 3 1 0 0 0 HE A2 B2 C2 4 5 0 2 EG EN Figure 8 21 HE card examples the coil on the right has a negative R EM Software 4 Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 31 8 2 16 IN Card This card is used to include external files These files may be other pre files which are included as if they were part of the master file or geometrical data files containing wire segments triangles quadrangles tetrahedral volume elements and or polygonal plates in FEMAP neutral an ASCII format NASTRAN meshed AutoCAD dxf NEC model Concept model or STL files The syntax for the IN card is somewhat different from the other cards The fields are separated by an arbitrary number of spaces and the general format is IN FL
330. oint of segment k s2 k Number index of the end point of segment k nnp m Number of corner points in polygon m pl m Number index of the first corner of polygon m p2 m Number index of the second corner of polygon m p3 m Number index of the third corner of polygon m Number index of the additional corners of polygon m December 2002 FEKO User s Manual DESCRIPTION OF THE GEOMETRY CARDS tl n Number index of the first node point of tetrahedra n t2 n Number index of the second node point of tetrahedra n t3 n Number index of the third node point of tetrahedra n 14 n Number index of the fourth node point of tetrahedra n String name Optional string name of the point It must be a string of up to 5 characters similar to the point name of the DP card If a point is named it can be used in any card following the IN card Label Specifying the label as the last parameter of any structure is optional If no label is specified the value defined at the last LA card will be used Note that if a label or range of labels is specified with parameters after the filename this LA card label will be used to determine if a structure is included or not The radius of segments must be specified by an IP card before the IN card It is recommended to check the geometry with WinFEKO Example The structure in figure 8 22 consisting of 5 node points and 3 triangles with label 7 no segments or polygonal plates may be generated with
331. ometric data is possible Parameters SKALFLAG Determines what should be scaled 0 All geometrical dimensions are scaled with the factor SKAL but not the coordinates for near field calculations or excita tions see the discussion below 1 All geometrical and coordinate dimensions are scaled SKAL The scaling factor for example if SKAL 0 001 all dimensions are entered in mm All geometrical dimensions and or coordinates are multiplied by the factor SKAL This is necessary when the input coordinates are not in metre but for example in cm In this case the geometry has to be scaled by a factor of 107 Only one SF card is allowed in the input file This is global and can be positioned anywhere However since it is a geometry card it must be before the EG card The mode SKALFLAG 0 is supported for compatibility with existing input files For new input files it is strongly recommended to use the mode SKALFLAG 1 In the SKALFLAG 0 mode the following is scaled e Coordinates of the corner points of the triangular surface elements e Coordinates of the corner points of the segments e Radii of the segments e Coordinates of the corner points of the cuboids Radii of the all the layers when the Green s function for a homogeneous or layered dielectric sphere is used GF card section 9 2 27 e Thickness of the layers when the Green s function for a planar multilayered sub strate is used GF card section 9 2 27 e Coordina
332. on maxalloc 100 1024 1024 will allow a maximum of 100 MByte of memory to be allocated This parameter has been replaced by maxallocm see above but it is still understood for backwards compatibility purposes 2 6 2 Other variables that are under user control In some cases memory blocks have to be allocated for data storage before FEKO knows exactly how big these memory blocks have to be In these cases it uses an estimate calculated by PREFEKO If the estimated size is too small FEKO will stop execution and give an error message The appropriate size now has to be declared in the pre file This is done by entering for example the line maxnv 100 as for normal variables see also section 6 3 anywhere in the pre file maxnp The maximum number of columns and rows which a block in the ma trix consists of in the Block Gauss algorithm which solves the matrix equation Dynamically 3 maxnp maxnp 16 bytes are allocated for 3 blocks in the matrix maxnv The maximum number of connection points between wires and sur face triangles 2 6 3 Variables that are automatically set correctly Note that normally PREFEKO estimates the following variables correctly and they should only be declared in cases where there is an explicit error message stating that larger mem ory blocks are required Under normal circumstances these variables should not be set they could have a negative impact on the FEKO performance maxaeedges The
333. on with measured results e plausibility e g negative real input impedances do not exist If these possibilities are not available then the following should be tried e After a normal calculation with FEKO run another pass with a finer mesh see IP card section 8 2 17 The number of segments should be at least 1 5 times greater than with the normal calculation If there is a large difference in the results then an error has occurred e Doing a power balance The power fed into an antenna through the power source must be equal to the radiated power The radiated power can be calculated by integrating the power flux density This is done by using the FF command see example_07 or example_08 in the Examples Guide EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM WINFEKO 3 1 3 The program WinFEKO The program WinFEKO has been developed to serve as a Graphical User Interface GUI for FEKO in a MS Windows environment WinFEKO uses the dynamic link libraries OpenGL32 d11 and G1u32 d11 which should be available on all NT 2000 XP systems and most 95 98 ME systems The libraries for Windows 95 98 ME are included on the FEKO CD in the directory utils OpenGL95 If they are not available on your system copy them from the CD to your FEKO installation directory WinFEKO also use the libraries Glut32 d11 and GLPrint ocx which are installed with FEKO In addition it calls the program GraphFEKO developed for the extraction of dat
334. ond FE card The structure of the single files is described below efe file When calculating the electric near field in Cartesian coordinates there are columns with the position in x y and z as well as the field components Ez Ey and E in complex form In cylindrical coordinate the columns consist of the following r p 2 Er Ej and E In spherical coordinates the columns consist of the following r 9 p Er Ey Ey EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 51 hfe file Same form as the efe file except that the magnetic field values are given ffe file Here the angles Y and are given Following them are the field components x Ey and E in complex form with the factor a left out as in the output file Then the gain in dB separated into the polarisation directions or the radar cross section is given os file First the triangle numbers and the centroids x y and z are given as well as the complex current densities Jz Jy and J at the centroid Then there are three values which give the absolute value of the current density at the three corner points as averaged over all triangles that are adjacent to the corner points The next three complex values are the components of the complex current density vector J for the first corner point of the triangle The following groups of three are the values for the second and third corner points of the triangles After the c
335. one node will be fed Alternatively one may set ULA 1 then the feed node is determined by specifying its Cartesian coordinates r EIR3 y EIR4 and z EIR5 EIR1 Absolute value of the voltage source Uo in V EIR2 Phase of the voltage source Uy in degrees EIR3 Only if ULA 1 the x coordinate of the feed node in m EIR4 Only if ULA 1 the y coordinate of the feed node in m EIR5 Only if ULA 1 the z coordinate of the feed node in m The values EIR3 EIR4 and EIR5 are scaled by the SF card if SKALFLAG 1 EIR6 The port impedance if this excitation is used in connection with S parameter calculation If this field is empty or 0 the value specified at the SP card is used This value is only used if the S parameters are requested with an SP card There may not be more than two segments connected to the node The direction of the vector points in the same direction as the basis function that has been assigned to this node When only one segment is connected to the node the direction is away from the segment This is the direction of the current flow through the node The internal EMF electromagnetic force of the impressed voltage is in the opposite direction EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 13 9 2 6 A3 Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 NFL ULA EIR1 EIR2 EIR3 EIR4 EIR5 EIR6 EIR7 EIR8 IE REAL REAL REAL REAL REAL REAL REAL REAL This card realises exc
336. only one medium was allowed and the parameter MED did not exist if the parameter MED is not specified i e input field is empty then this defaults to MED 1 and hence sets the material parameters of medium 1 Using MED 0 will overwrite the default free space parameters that might have been set at the EG card or at a previous GF card for the free space Green s function EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 53 9 2 23 EN Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 o NT R NT NT REAL REAL REAL REAL REAL REAL REAL REAL This card indicates the end of the input file It is essential and has no parameters December 2002 FEKO User s Manual 9 54 DESCRIPTION OF THE CONTROL CARDS 9 2 24 FE Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 FEL ANZXANZYANZZ FEL xo Yo ZO DX DY DZ R8 TYP KOR A IE REAL REAL REAL REAL REAL REAL REAL REAL This card controls the calculation of the near fields Parameters FELTYP 0 Field is not calculated 1 Calculate the electric field in free space 2 Calculate the magnetic field in free space 3 Calculate both electric and magnetic fields in free space 7 Outputs the electric field as well as the SAR values in the dielectric volume elements The other parameters e g ob servation points are not required 10 Compute the magnetic vector potential A 11 Compute the gradient of the scalar electric potential V y 12 Compu
337. onsisting of dielectric cuboids can be created Figure 8 16 Sketch illustrating the use of the DZ card Parameters S1 Name of the begin point of the cylinder s axis S2 Name of the outside of the cylinder S3 Name of a point that lies on the inside of the shell see figure 8 16 S4 Name of a point that lies on the outside of the shell see figure 8 16 Ri Angle p in degrees of the cylindrical segment R Maximum edge length of the cuboids along the arc in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used Only applicable to a dielectric cylinder R3 Relative dielectric constant e of the cylinder R Conductivity o in of the cylinder Rs The density o in me of the cylinder This parameter is only required to calculate the SAR specific absorption rate but it is compulsory and must always be defined Rg The electric loss tangent tan 0 December 2002 FEKO User s Manual 8 22 DESCRIPTION OF THE GEOMETRY CARDS Only applicable to a magnetic cylinder Re Relative permeability ur of the magnetic cylinder Rz The magnetic loss factor tan 0 No dielectric bodies with surface equivalence principle and volume equivalence principle using cuboids can be used at the same time Example of DZ card usage Using the following command the cylindrical segment as shown in figure 8 17 is created IP 0 3 DP DP DP DP DZ EG EN gt oae o a O O G O
338. op of the file the cursor must be moved there using lt Ctrl gt lt Home gt Note that there is also a fast card search By right clicking on any button on the button panel the next occurrence starting from the current cursor position of the associated card is found 4 2 6 Run menu This allows PREFEKO the FEKO solver WinFEKO and GraphFEKO to be run from inside EditFEKO Note that when running PREFEKO or FEKO the current file is saved without confirmation For WinFEKO and GraphFEKO this is not the case as they do not read the pre file This menu also allows passing parameters to PREFEKO and FEKO see section 6 for PREFEKO and section 7 2 for FEKO 43 OPTFEKO mode In this mode the OPTFEKO control blocks can be edited The cursor must be on the keyword of the specific block in order to edit it with lt F1 gt In the block of variables only the variables from the current line downwards will be edited thus the cursor should be on the first line of the variable block when editing it The comment buttons will add a comment line regarding the particular block and in some cases also captions for the different input fields in the block EM Software amp Systems S A Pty Ltd December 2002 THE EDITOR EDITFEKO 4 7 4 4 Important keystrokes The arrow keys as well as lt Pg Up gt and lt Pg Dn gt behave in the normal fashion The following keys may be different to some other applications Cursor Movements Move a word le
339. op when NFREQ points are reached of course one can set DFREQ to be the minimum allowable separation distance between neigh bouring frequency sample points The value of DFREQ must be smaller than the resolution required to solve for example sharp resonances If left empty the default is 1 0e 4 FREQE FREQO FREQE Ending frequency in Hz not optional in this case If a discrete loop with more that one frequency is required FREQF42 NFREQ 1 then either DFREQ or FREQE must specified but not both If the end frequency FREQE is specified DFREQ is calculated from e for FREQF 0 additive increments FREQE FREQO DFREQ Q NFREQ 1 e for FREQF 1 multiplicative increments 1 FREQE NFREQ 1 DFREQ Q FREQO When writing results at discrete frequencies to a isd file the frequency increment when I 0 is calculated similar to the case for FREQF 0 above with NFREQ replaced by Iz and the factor for I4 1 is similar to that for FREQF 1 If more than one frequency is to be examined then all the control cards up to the next FR card or EN card will be read into a buffer and are executed for each frequency More information can be found in section 9 1 EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 67 9 2 27 GF Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 GF I2 I5 Ri Ra R3 Ra Rs Re R7 LA TR ae eae ae NT REAL REAL REAL REAL REAL REAL REAL REAL W
340. or all processes 3 Interlaced only for testing not stable The location of the files can be set through the use of the environ ment variable FEKO_TMPDIR see section 2 7 Note that I can be set without setting J Certain parts of the program that are present for development and debugging e g the use of symmetry in the SY card without saving computational time or the parts that still are under development and testing can only be run in the superuser mode EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 91 8 2 34 SY Card t 6 10 15 20 25 30 40 50 60 70 80 90 100 110 IE REAL REAL REAL REAL REAL REAL REAL REAL Here symmetry can be used to generate the geometry and to reduce computation time Parameters I 1 Employ symmetry to save CPU time 0 Mirroring the geometry but not using the symmetry to save CPU time This option is only available during program development and cannot be activated by normal users I gt Mirroring around the plane 0 or yz plane 1 The plane x 0 represents geometric symmetry 2 The plane x 0 represents electric symmetry 3 The plane z 0 represents magnetic symmetry 3 Mirroring around the plane y 0 az plane 1 The plane y 0 represents geometric symmetry 2 The plane y 0 represents electric symmetry 3 The plane y 0 represents magnetic symmetry I4 Mirroring around the plane z 0 xy plane 1 The plane z 0 repres
341. ory where FEKO has been installed It gives a basic introduction to FEKO and the different FEKO modules It is also recommended that new users read the General Comments Chapter 2 of this FEKO User s Manual carefully Various simple FEKO examples that show the application of the various cards are are discussed in the Examples Guide Changes in this manual with respect to the previous manual of March 2002 Suite 3 2 are indicated as follows Sections that has changed from those in the previous version of the manual Sections that were newly added to this version of the manual EM Software amp Systems S A Pty Ltd December 2002 GENERAL COMMENTS 2 1 2 General comments 2 1 Structure of the input file The program is card driven similar to the thin wire MoM code NEC An input file consists of various cards high level commands which can be categorised into geometry cards and control cards The geometry and the field parameters to be calculated are specified using these cards Certain geometric cards are interpreted and filtered out by the preprocessor PREFEKO and translated into other cards The basic form of the input cards is 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 Per Ii I2 73 Ja I5 R R2 R3 R4 R5 Re R7 Rg TA R EN TE REAL REAL REAL REAL REAL REAL REAL REAL The upper numbers indicate the columns The name field in columns 1 and 2 specifies the type of the card This is followed by five integer parameters
342. ough the use of the following commands the parallelogram in figure 8 5 is created eK IP DP DP DP DP BP EG EN gt U0Q0Uu Fer OO O O O O oro oo 0 0 N Orero D O O G Figure 8 5 Example for the BP card December 2002 FEKO User s Manual 8 8 DESCRIPTION OF THE GEOMETRY CARDS 8 2 4 BQ Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ry Ra R3 R4 R ae uae No NT REAL REAL REAL REAL REAL REAL REAL REAL With this card four points are connected to form a quadrangle The quadrangle is then subdivided into triangles An example is shown in figure 8 6 S S S S Figure 8 6 Sketch illustrating the use of the BQ card Parameters S Name of the first point of the quadrangle S2 Name of the second point of the quadrangle S3 Name of the third point of the quadrangle S4 Name of the fourth point of the quadrangle R Normally the quadrangle is segmented according to the triangle edge length specified with the IP card However it is often desirable to have an inhomogeneous segmentation for example in the transition from a finely segmented region to a region with coarser segmentation If set the parameter R specifies the triangle edge length along the edge 51 52 R is in m and is affected by the SF card scaling factor R Similar to R but applies to the edge S2 83 Rs Similar to R but applies to the edge S3 S4 R Similar to R but applies to th
343. parameter Re around the x axis The rotation is identical to the rotation executed by the TG card in section 8 2 35 and the rotation matrix M is applicable to the both the TG and AR cards Finally the pattern is shifted to the location specified by the parameters R3 Ra and Rs If the AR card is used simultaneously with a ground plane BO card FEKO automati cally includes the influence of the ground plane on the radiation pattern The imported pattern must therefore be the free space radiation pattern of the antenna in the absence of the ground plane If this is not the case the influence of the ground plane is considered twice The use of the PW card to specify the radiated power is allowed The field amplitudes ESF and E will be scaled accordingly Multiple radiation patterns can be used simultaneously and also with other sources such as an incident plane wave In such a case the coupling is not considered when the radiated power is determined The AR card cannot be used with special Green s functions for a layered sphere or for a layered substrate We conclude this description with a couple of examples e Importing an ffe file Above we stated that the commands DA 0 0 1 0 0 FF 1 37 T3 0 0 0 0 0 5 0 5 0 create a complete radiation pattern of an antenna in 5 increments This can then be imported as source into another model with the command AR 0 1 1 37 73 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 file ffe December 20
344. parameters are ignored EPSRF The relative dielectric constant e of the ground SIGRF The conductivity o in of the ground MUERF The relative permeability ur of the ground TANDMUERF Magnetic loss factor tan of the ground the complex perme ability is then given by u Hokr 1 jtand TANDEPSRF Electric loss factor tan 6 an alternative way to specify the con ductivity the two loss terms are related by tan e and they have different frequency behaviour It should be noted that it is not possible to calculate the fields below the ground plane i e it is not possible to calculate the fields in the region z lt 0 In addition all structures must be in the region z gt 0 If calculations in the ground are required for example when there are structures below ground the use of the exact Sommerfeld integrals GF card is recommended When using a perfect electric or magnetic reflection coeffiecient ground plane structures can be arbitrarily close to the ground while remaining above it Note that structures cannot make electrical contact with the ground If this is required electric symmetry should be used see the SY card in section 8 2 34 December 2002 FEKO User s Manual 9 42 DESCRIPTION OF THE CONTROL CARDS If real ground parameters are used the reflection coefficient approximation is more ac curate for structures further from the ground plane Typically structures should not be closer than about F
345. ph button sends data for the selected quantities to the active graph window and the Cancel button closes the Current extraction panel and activates the Main graph settings panel Plotting the induced current as a function of frequency The induced current I gt in the specified segment can be plotted as a function of frequency in the same way as described for receiving antenna parameters in the previous section Only one excitation may be selected but multiple segments may be simultaneously plotted against frequency December 2002 FEKO User s Manual 5 12 THE PROGRAM GRAPHFEKO Plotting the induced current on a number of segments If a single frequency and a single excitation have been selected and multiple segment currents are available for this combination as written with the OS card a list of segments can be selected in the Segments list The Independent parameter field then becomes visible If the segnr is selected in this field the currents are plotted in the order they appear in the output file This order depends on the way in which the model is created and usually does not reflect an intuitive order The user may therefore elect to plot the segment currents as a function of one of the Cartesian coordinates This allows one for example to plot the current on a dipole antenna as a function of the position along the dipole 5 3 2 8 Far fields When this item is selected GraphFEKO loads the far field data if it exists from the
346. planar apertures for example the opening of a horn antenna one may use the mirror principle if the field at the edges can be neglected This results in a duplication of the magnetic current and cancellation of the electric current Thus it is sufficient to read only the electric fields and scale by the factor AMP 2 In this case any sources or structures in the region towards which the normal is pointing should also be subjected to the mirroring i e the structures should be electrically mirrored by using the SY card Further it should be remembered that the fields will only be correct in the direction that the normal vector points to The symmetric fields in the other half space will not be equal to the fields of the original problem Note that FEKO takes this into account and divides the total radiated power by two when calculating the power radiated by a planar aperture containing only electric or magnetic fields The parameter TYPE is also used to determine the format of the data file For TYPE 1 2 5 15 and 25 the fields are calculated in FEKO FE card and written to efe and hfe files on request of the DA card Note again that the position distance data in the files is not used but the angle information is used December 2002 FEKO User s Manual 9 32 DESCRIPTION OF THE CONTROL CARDS For TYPE 3 4 6 16 or 26 the data is read from an ASCII format text file Each line in the file represents one point
347. plate will create a FEKO input file without any control cards Click the Create project button A new directory will be created in the selected path The name of the directory will be the selected Project name e g dipole In this directory three files will be created with the same name as the directory or project name The three files are the FEKO input file pre file a WinFEKO project file wfp and a FEMAP model file mod 3 5 1 2 Open project Select the Open project item to open an existing FEKO project The project that is open at the time if any will first be closed The default extension when browsing for the project to open is wfp WinFEKO project extension Select a different file type if no wfp file exist For example if only PREFEKO input files pre files exist select PREFEKO file as the file type If a wfp file is selected information regarding this project is loaded for example the previous zoom factor view angles etc If a pre file or fek file is loaded and no w p file exists the default program settings are chosen for the model In such a case it is recommended that the project be saved immediately select File Save project This will create a wfp file to associate with this pre or fek file WinFEKO searches for a fek file in the current directory with the same name as the selected wfp pre or fek file If the fek file is found the model information is loaded
348. point situated on the surface on the toroidal segment It must be in the plane formed by the three points S1 S2 and S3 Ri The angle in degrees of rotation around the axis 51 53 R The angle a in degrees see figure 8 53 R The maximum edge length along the curved edge in the direction in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used R The maximum edge length along the curved edge in the a direction in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used Rs Indicates the direction of the normal vector 0 Normal vector points to exterior 1 Normal vector points to interior December 2002 FEKO User s Manual 8 96 DESCRIPTION OF THE GEOMETRY CARDS Re If this parameter is empty or is set to 1 a toroid with a circular cross section is created The parameter Rg may be used to generate an elliptical cross section in the a plane Re 2 gives the ratio of the ellipse s two half axes where a is the distance S3 S4 It is rec ommended to generate toroids where the elliptical cross section have extremely small or extremely large axial ratios with a CAD system such as FEMAP as the distortion formulation used in PREFEKO may fail in these cases A complete toroid is obtained by using the parameters y 360 and a 360 The normal vector generated by the triangles points to the outside First example of TO card us
349. pre files For example in a pre file which will be optimised with respect to the variable a one may use 11if not defined a then a 200 0e 3 lendif The order of precedence is lower levels are evaluated first is OR AND and lt gt gt lt gt and lt and and and when used as sign function calls single number expressions in brackets EM Software amp Systems S A Pty Ltd December 2002 THE PREPROCESSOR PREFEKO 6 5 Some variables are predefined in PREFEKO but may be overwritten by re assignments These are Name Value Description pi 3 14159265358979 The constant 7 epsO 8 85418781761 107 Dielectric constant o of free space mu0 471 1077 Permeability uy of free space c0 Ws The speed of light in free space zf0 on The intrinsic impedance of free space true 1 Used for logical true false 0 Used for logical false There are three other special variables x y and z which are very useful for the connection of complex wire structures The three variables specify the Cartesian coordi nates of the end point of the wire segment most recently defined This enables the correct and easy connection of a straight wire to a curved length of wire as the next extract from an input file demonstrates 0 aa DP A x ly iz z z 0 5 DP B x ly z BL A B The following example demonstrates the use of variables A dielectric sphere in the field of an incident
350. putation time To do this one may use the variable freq which is constantly changed by TIMEFEKO in the definition of the segmentation parameters Example Define some constants maxfreq 250 0e 08 minlambda cO maxfreq Define the edge length note the use of freq ttedgelen 2 0 freq maxfreq minlamdba 4 0 Set the segmentation parameters IP edgelen 11 3 The tim input file In the file tim the pulse form position and the point in time are assigned This file consists of a number of sections which are optional at present Set the pulse form with characteristic value and the time shift Set the size of the highest frequency and the sampling points Set the normalisation normalise time to the speed of light Set whether the output is written to the output file Set the time points In the tim file empty or comment lines starting with are allowed The parameters need not be entered in any particular column but they have to be in the correct order The keywords used in the tim file exist in German and English for example ANREGUNG and EXCITATION Both versions of each keyword will be given in the discussion below TIMEFEKO will recognise keywords in either language independent of the language selected by the environment variable FEKOLANG 11 3 1 Defining the pulse form The assignment of the pulse form is necessary Each pulse has a predefined name and has particular characteristic parameters The
351. quantity in dB If any of the quantities selected have negative values and either Log or dB scaling has been selected then a warning will be given and the graph will be plotted on a linear scale One may also elect to plot the input impedance on the Smith chart See the comments on setting labels and the grid density of Smith charts in the previous section 5 3 2 5 Network parameters When this item is selected GraphFEKO loads the network parameter data if it exists from the selected FEKO output file and activates the Network parameters panel Network parameters only exist if the output file contains currents on segments written with the OS card which were calculated for voltage sources The various frequencies at which the FEKO solution has been obtained are displayed in the Frequency box The Source nr field lists the sources for each frequency in the order they appear in the output file If two voltage sources are active at the same time they are listed separately The Source nr field only affects J and S11 information EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM GRAPHFEKO 5 9 The Block nr field specifies the solution blocks available at each frequency It is incre mented each time the currents is recalculated If only one source is active at a time it should be equal to the Source nr field The Cur block field allows the user to select the nh OS card for the given frequency and solution block The Segments
352. r Efficient wide band evaluation of mobile commu nications antennas using Z or Y matrix interpolation with the method of moments by K L Virga and Y Rahmat Samii in the JEEE Transactions on Antennas and Propaga tion vol 47 pp 65 76 January 1999 In that paper they considered the input admittance of a forked monopole For comparison we have plotted the input admittance scaled it to mSiemens and scaled the bottom axis to h A with h lm Since we consider a dipole while their example uses a monopole we need to multiply the admittance with a further factor of 2 The result is shown in figure 13 4 and compares very well to the published result Re Z_in Im Z_in 2 500 2 000 1500 e o Q o Impedance Ohm Al a a E ES 50 75 100 125 150 175 200 225 250 275 300 Frequency MHz Figure 13 2 Input impedance of the forked dipole EM Software 4 Systems S A Pty Ltd December 2002 THE PROGRAM ADAPTFEKO 13 5 Re Z_in e Im Z_in 500 Impedance Ohm 1 000 1 500 202 203 204 205 206 207 Frequency MHz Figure 13 3 Input impedance of the forked dipole around the resonance point The squares and circles represent values calculated at the discrete frequencies The marker at 206 2 MHz denotes the only adaptive sample point in this band 40 i i i i i i i Re Y_in 35 r i i i Im Y_in 30 25 20 Admittance mSiemens 0 2 0 3 0 4 0 5 0 6 0 7
353. r x has the following meaning 1 Wire segments 2 Surface triangles 4 Polygonal plates 8 Tetrahedral elements 16 Points 32 Quadrangles subdivided into two triangles during import 64 Points but only those used by the geometry December 2002 FEKO User s Manual 8 32 DESCRIPTION OF THE GEOMETRY CARDS It is possible to add these options i e for x 1 2 3 both wire segments and trian gles shall be imported provided they also satisfy the label criterion but no polygonal plates tetrahedral volume elements or points Quadrangles are sometimes grouped with triangles and sometimes considered separately The default when the parameter x is not specified is to include all structures but not points these must be requested explicitly that satisfy the label criterion Note that some of these options may not be supported for a given file type See the description for the different file types below Scaling An optional constant scaling factor can be applied to the imported geometry This is necessary for example if separate CAD files with different units must be imported or if the pre is for example created using mm while the CAD file is constructed using inches as unit Scaling is specified by adding the character string scaling it ends with a semicolon at the end of the card The syntax is then for example IN 2 4 filename dat scaling 0 001 IN 2 filename dat 7 scaling 0 001 IN 1 filename neu 0 3 scaling 0 001
354. ral settings tabs Then click the Save button and save it as winfeko cfg in the FEKO home directory The general settings can also be saved in any other configuration file for later use Such settings can be loaded by clicking the Load button and selecting the appropriate configuration file To save the settings associated with a WinFEKO project make the appropriate changes under all General settings tabs hit the Apply or OK button and save the project The different general settings options will now be described 1 Display Under Element info Offset Direction select Normal to display element information at a fixed 3D position next to the element e g with triangles this position is in the direction of the normal vector associated with the triangle Select View to display element information always in the direction of the user s view point This last option is useful when element information is hidden behind geometric elements in the model Under Request Field Info select the colour in which the requested near and far fields must be displayed on the screen This is not the result data but the positions of the requested fields as defined by the FE and FF cards Under Axis Length set the length of the axis With this values set to zero a default axis length will be calculated and used by WinFEKO The AP card is converted to dipole sources These are normally rendered as arrows which may require a large amount of RAM and rendering time
355. rd layer Conductivity in of the third layer Electric loss factor tan 6 of the third layer an alternative to the conductivity a the loss terms are related by tan 52 Magnetic loss factor tan of the third layer the complex per meability is then given by y our 1 j tand For GFFLAG 4 the GF card must be followed by three additional lines with the characteristics of the second and first layers as well as the core in this order December 2002 9 69 FEKO User s Manual 9 70 DESCRIPTION OF THE CONTROL CARDS for GFFLAG 5 Ri Sphere s radius in m is scaled by the SF card Ra Relative dielectric constant p Rs Relative permeability pr R Conductivity o in g Re Electric loss factor tan an alternative to specifying the con ductivity o the two loss terms are related by tan 27 Rz Magnetic loss factor tan 6 the complex permeability is then given by u Hor 1 jtand for GFFLAG 6 R Radius of the outer most layer in m is scaled by the SF card R Relative dielectric constant of the second layer Rs Relative permeability ur of the third layer R4 Conductivity o in aof the third layer Rs Electric loss factor tan of the third layer an alternative to specifying the conductivity the two loss terms are related by tand 525 Rz Magnetic loss factor tan of the third layer the complex per meability is then given by y our 1 j tand For GFFLAG
356. re defined in the frequency block FREQUENZ FREQUENCY Example FREQUENCY Upper frequency limit Number of frequency points 250 OE 06 34 The maximum frequency fmaz should be large enough such that the whole spectrum of the exciting pulse is covered For example for the Gaussian pulse GAUSS of section 11 3 1 we find faaB ly Inv2 x 0 187 a T with a as defined in equation 11 1 One should select approximately fmaz 4 fap The number of frequency points N is then selected such that the total time T is long enough for the exciting pulse and all included currents radiated fields etc to have de cayed Once one has determined the total time the number of samples may be determined from the relation 1 Fried SSB Waa or N 14T finaz 11 8 EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM TIMEFEKO 11 7 Finally let P be the smallest power of 2 which is larger than or equal to N 1 For example for N 10 P 16 for N 33 P 32 and for N 50 P 64 Then the time stepping will be At aa TPP With the relation lt N 1 lt P we get the bounds lt At lt 4 Ima 2 tivas 11 3 3 Definitions of the normalisation Using the keyword NORM NORM the time can be normalised to the speed of light in a vacuum co The normalised time then has a unit of lm light metre tnorm t Co Example Normalising time with respect to the speed of light NORM 11 3 4 Definition of
357. re running a parallel job MPICH NT must be configured properly A default ma chines file see section 7 2 2 was created during installation This may also be configured for the local user Select Solver Parallel version Configure from the main menu to open the configuration window The configuration window allows the user to specify the host names and the number of processes to run on each host FEKO must be installed in the same location on each host Usually one would run one process per CPU which de termines the number of processes for each host for example 2 processes for a dual board machine One may also use this for a crude load balancing running more processes on hosts with faster CPUs or more RAM The Add hosts line button creates room to specify additional hosts We recommend that the parallel job is started from a PC that forms part of the cluster and that this host is listed first If the Check node performance and Check network performance options are selected FEKO will also print a table giving the performance of the various nodes It is rec ommended that this is used during setup to ensure an optimum configuration These checks are repeated each time FEKO calculates the solution so it may require a signif icant amount of time if the test file contains multiple frequencies One would not keep these options selected after the initial setup except for debugging purposes It is possible to launch the job wit
358. rent of the two waves propagating along the line It does not specify any losses Ra Real part of the shunt admittance at port 1 in Siemens This admittance is across the port connecting the two wires of the transmission line Rs Imaginary part of the shunt admittance at port 1 in Siemens Rg Real part of the shunt admittance at port 2 in Siemens R Imaginary part of the shunt admittance at port 2 in Siemens Rg Losses of the transmission line in dB m Note that since the propagation constant is taken as the propagation constant of the medium in which the start and end segments are located the attenuation specified by Rg is added to any losses of this medium This factor is not affected by the scaling factor spec ified with the SF card i e if a scaling factor which reduces the length of the transmission line is added the total loss through the line will be less as the loss is still Rg in dB m For Iz 1 or 3 1 follows a second line Ri x coordinate of the centre of the port 1 segment in metres The scaling factor of SF card applies R y coordinate of the centre of the port 1 segment Ra z coordinate of the centre of the port 1 segment Ra x coordinate of the centre of the port 2 segment Rs y coordinate of the centre of the port 2 segment Re z coordinate of the centre of the port 2 segment An arbitrary number of transmission lines can be used also one wire segment could be for instance the end of one tra
359. rge axial ratios with a CAD system such as FEMAP as the distortion formulation used in PREFEKO may fail in these cases The circle s plane is perpendicular to the line S S3 This length is arbitrary The radius of the disc is given by the length between the points S3 and Si The area that is to be subdivided the shaded region in figure 8 29 is generated by sweeping the edge S3 S around the axis S S2 through y degrees in the mathematically positive sense For y 360 a circle is obtained The fineness of the mesh is determined by the maximum edge length specified by the last IP card prior to the KR card Along the arcs accurate modelling of the geometry may require finer segmentation and the values Ra and Rg specify the maximum edge length along the outer and inner if applicable arcs respectively If either of these values is not specified the length specified with the IP card will be used on the corresponding arc The normal vector of the triangles on the disk all point in the direction from S to S2 First example of KR card usage Using the following commands the circular disc shown in figure 8 30 is created IP 0 4 DP A 0 0 0 0 0 0 DP B 0 0 0 0 1 0 DP C 1 0 0 0 0 0 KR A B Cc 360 0 0 35 EG EN Second example of KR card usage Using the following commands the circular disc shown in figure 8 31 is created IP DP DP DP DP KR EG EN O O 0 0 O 0 0 0 gt U0Q0ur WoOodddw oo OF Oo
360. rion of Ig and I are processed Tetrahedral volume elements that satisfy the label criterion of I and 13 are processed Is can assume the tabulated values directly It is also possible to add the options in a binary fashion For example setting J5 1 2 38 all metallic triangles and segments with the correct label are processed Angle of rotation a around the x axis in degrees Angle of rotation a around the y axis in degrees Angle of rotation a around the z axis in degrees Translation A in the x direction in m scaled by SF card Translation A in the y direction in m scaled by SF card Translation A in the z direction in m scaled by SF card The scaling factor y with which the structures must be scaled if the parameter R7 is not specified it defaults to y 1 For wire segments the wire radius is scaled as well as the coordinates of the start and end points 8 93 When an SY card symmetry is used before the TG card the TG card resets the sym metry if the new structures invalidates the symmetry Cases where the symmetry is not reset is when for example the plane z 0 is a symmetry plane and the TG card spec ifies rotation about the z axis for a symmetrical selection of elements In this case the symmetry is retained With a TG card the simultaneous rotation around multiple axes as well as translation in multiple directions is possible A point a y z for example the corner point of a December 2002
361. rol the model rendering 1 Normalise to extent With this button the zoom factor is set such that the complete model will fit into the display window The extent is calculated from all geometrical elements in the model including the node points DP card and the axes as well as the requested field points in the model 2 Isometric view and normalisation The same as Normalise to extent but the view direction is set to the default 0 65 p 35 3 Zoom to window Click this button to zoom to a specific rectangular window After clicking the button do the following left click hold down and drag on the display to select the window to zoom to Release the left mouse button to execute the zoom to window December 2002 FEKO User s Manual 3 6 THE PROGRAM WINFEKO 4 Previous view Returns the display to the previous view Zoom factor view angles and pan positions are remembered 5 Zoom in by a constant factor The default constant factor is 25 but it can be set under Transformation control Zoom see section 3 5 7 2 6 Zoom out by a constant factor The default constant factor is 25 but it can be set under Transformation control Zoom see section 3 5 7 2 7 Pan left by a constant factor The default constant factor is 10 100 represents panning horizontally across the display screen 8 Pan right by a constant factor The default constant factor is 10 100 represents panning horizontally across t
362. rrectly for PREFEKO to start successfully from the WinFEKO environment This should have been done automatically by the FEKO installation program See the Getting Started manual 3 5 2 5 Display FEKO model The fek file associated with the current project is loaded and displayed when this item is selected A FEKO model file e g dipole fek is created as output when the program PREFEKO is executed If no fek file with the project name is available in the current project path a standard open dialog is activated This allows for the selection of any other fek file If WinFEKO experiences problems on trying to load the selected fek file no FEKO model will be displayed An error or warning should appear and this will give a hint to what might be wrong with the fek file On successful loading and display of a fek file an identification legend FEK File is drawn at the bottom of the display window 3 5 2 6 Clear This item clears all information associated with the geometry and output data of the current project The project is not closed but no FEK or NEU model will be displayed Effectively this command releases all memory allocated when loading the FEK or NEU file geometries or the output file data It is recommended to use this command before running the FEKO solver from within WinFEKO on large FEKO problems 3 5 3 Solve menu 3 5 3 1 Run solver Select the Run solver item to execute the sequential FEKO solv
363. s an ohmic connection This is shown on the left side in figure 2 2 The line AB is divided into four segments and the point C is not on a node To resolve this problem three wires have to be defined AC CB and CD Then there will be an ohmic connection at point C as shown in figure 2 2 on the right D A B C Figure 2 1 Example of a wire structure EM Software 4 Systems S A Pty Ltd December 2002 GENERAL COMMENTS 2 5 Figure 2 2 Incorrect left and correct right subdivision into segments A similar rule has to be followed when surfaces are to be subdivided into triangles If the surface in figure 2 3 has to be meshed there are a number of possibilities The surface can be subdivided into the rectangles ABFG and CDEF This can result in the mesh shown in figure 2 4 on the left hand side In this case there is no ohmic connection at the line BF because the triangles vertices are not connected in the sense that the triangles do not have common edges The correct subdivision of the surface shown in figure 2 3 is shown in figure 2 4 in the middle Here the rectangles ABFG CDHB and BHEF were used Another subdivision is possible using rectangles ABEG and BCDE figure 2 4 right side BE is now a common edge and the surface will be meshed correctly G F E A B H c D Figure 2 3 Example for a surface SAN SSR Figure 2 4 Incorrect left and correct middle and right subdivision into triangles
364. s column then a symmetric edge does not exist The same applies to the next columns xz and xy concerning the planes y 0 and z 0 The last column with the heading STATUS has the following meaning If unknown appears in it the edge has an unknown status The applicable coefficient of the current basis function cannot be determined from the symmetry but has to be determined form the solution of the matrix equation If 0 is present in the STATUS column then the coefficient of the current basis function is 0 due to electric or magnetic symmetry and does not have to be determined If there is any other number in the STATUS column then this number indicates another edge whose coefficient is equal to positive sign in the column STATUS or the negative of negative sign in the column STATUS of the coefficient of the current basis functions From symmetry the coefficient of the current triangle does not have to be determined The data of the dielectric triangles surface current method differ only slightly DATA OF THE DIELECTRIC TRIANGLES no label xl inm y1 in m zl inm edges medium x2 inm y2 inm z2 inm medium x3 inm y3 in m z3 inm nx ny nz area in m m 1 O 1 0000E 01 2 0000E 01 8 5000E 01 1 2 3 1 1 0000E 01 4 0000E 01 8 5000E 01 1 0000E 01 2 0000E 01 8 5000E 01 0 0000E 00 0 0000E 00 1 0000E 00 2 0000E 02 2 O 1 0000E 01 4 0000E 01 8 5000E 01 1 4 5 1 1 0000E 01 2 0000E 01 8 5000E 01 O 1 0000E 01 4 0000E 01 8 5000E 01 0 0000E 00
365. s of each keyword will be given in the discussion below OPTFEKO will recognise keywords in either language independent of the language selected by the environment variable FEKOLANG A documentation file example opt containing more detail is provided with the FEKO installation in the doc optfeko subdirectory The file is also located in the same directory on the FEKO CD 10 3 1 Definition of optimisation parameters The optimisation parameters are defined in tabular form Each optimisation parameter has a name a symbolic variable used but not numerically defined in the pre file For each parameter a start value as well as a minimum and maximum value have to be given Example The optimisation parameters follow Name Begin value Minimum Maximum ttalpha 20 80 80 ta 0 75 0 25 2 0 Normally the minimum and maximum values of the optimisation parameters as spec ified in the opt file are only used for the normalisation of the parameter space In order to ensure that the parameters stay within certain limits a penalty function see section 10 3 2 can be added This will result in a smooth aim function for the optimisa tion In some circumstances however sharp boundaries must be enforced to avoid invalid geometries for example the distance between points cannot become negative If the keyword ERZWINGE_MIN_MAX or ENFORCE_MIN_MAX is found in the opt file then the provided boundaries are strictly enforced when OPTFEKO
366. scaling offset and limits of the bottom axis Auto is selected by default but this is unselected if the user changes the axis limits Note that one must press lt Enter gt or exit the field after changing it before the changes will take effect If the current graph was created with ADAPTFEKO results it will contain markers showing the frequency samples along the bottom axis If these markers are present they can be hidden by unchecking the Show sample frequencies box One can also change their length and colour on this panel e Zooming in on graph details Zoom in on a specific region on a graph by clicking and dragging the mouse pointer on the graph top left to bottom right A rectangular window appears and when releasing the mouse button only the zoomed windowed region will be displayed on the graph Unzoom by clicking the Reset button that appears in the top left hand corner of the graph when zooming This option is only available for line graphs e Panning a graph Pan a graph by right clicking with the mouse on the graph hold down the right mouse button and move Unpan by clicking the Reset button that appears in the top left hand corner of the graph when zooming This option is only available for line graphs 5 3 3 2 Advanced edit This menu item will activate the GraphFEKO Advanced editor Various graph properties can be set here under the Chart tab top left The Series tab top right can be selected to edit the line setti
367. screte search GRID_SEARCH 20 20 Select the aim function Gain horizontal and vertical polarisation 1 data block GAIN 0 1 End The gain the negative aim function can be displayed graphically In figure 10 2 one can see a clear maximum in the area a 10 and 0 8 1 1 Distance a A o oO o N Gain in dB mox 0 6 0 5 60 40 20 0 20 Angle a in Deg 60 Figure 10 2 Gain as a function of the optimisation parameters EM Software amp Systems S A Pty Ltd December 2002 THE OPTIMISER OPTFEKO 10 19 The general position of the optimum is now known A new search can now begin with e g the simplex method by using the input opt below Input file for the optimiser OPTFEKO For a bent dipole in front of a reflector geometry in dipole pre Define optimisation parameters Name Begin value ttalpha 20 tta 0 8 Define penalty functions outside the optimisation region PENALTY_FUNCTION 100 100 10 10 Optimisation with the Simplex method SIMPLEX_METHOD 0 15 0 5 1 Optimise the gain GAIN 0 1 End OE 4 Minimum 20 0 7 1 0E 4 Maximum 40 0 9 both polarisations only 1 data block The extract from the log file reproduced below shows that the procedure a T and 0 78 No alpha 0000e 001 8693e 001 2329e 001 6364e 001 7671e 001 1307e 001 3636e 001 5653e 001 2471e 0
368. se the arrow buttons Select the Selected labels option under Label visibility to display entities associated with the selected labels Unselect any of the options under Element visibility to hide specific types of entities These options work together with the options available in the Main display options panel Select one of the options under Colours to determine how colours are used with the model display Select the Legend option in the Main display options panel for colour code identification The options are e Element type Use colour codes associated with wire segments metallic triangles dielectric triangles cuboids and UTD polygons This item is the default colour selection e EM properties Display entities associated with specific EM properties in different colours For example perfectly conducting metallic segments and loaded segments will be displayed in different colours e Label number Display the different fek file labels in different colours e Medium Display the different media in models using the surface equivalence prin ciple Select the More button top right to activate a panel with more FEK file display options Under Multi layer substrates select Enlarged substrates to draw the substrates at 10 times its actual thickness Select Draw lines to draw outlines on the substrates Select Show substrate no and then enter the numbers of the substrates that should be displayed in the adjacent edit box For exampl
369. se of 2 4 requires that y fe and e e where u ruo and the complex dielectric constant e 9 1 j tan jZ normally either or tan d is entered as zero A further condition is that the triangle should be geometrically thin i e d must be small relative to the lateral dimensions The mesh size is determined by the wavelength in the environment i e in the medium e He For a single layer the card consists of only one line The surface impedance as used by FEKO is then B 5 2jw E e tan 82 where 3 w ep is the propagation constant An example is given in example_32 Eramples Guide For multiple lines the card required one line per layer with the parameters of the first layer on the same line as the card name The approximate surface impedances of the different layers are added to determine the effective surface impedance I2 5 thin anisotropic dielectric layers This option is very similar to 2 4 but the layers are anisotropic The principle direction in each layer is defined by the angle a relative to the projection of the vector onto the plane of triangle Here a is measured in the mathematically positive sense with respect to the normal vector of the triangle WinFEKO can be used to display the fibre direction and visually check that the input file is correct In this case the card line is followed by an additional line for each layer If no SK card has been defined FEKO assumes idea
370. sible If geometrical symmetry is used then for POSYMFLAG 0 full ray tracing is done but for POSYMFLAG 1 symmetry is utilised It is possible to e g define half a plate and create the other half through symmetry An asymmetric object may then placed in front of the plate In this case only POSYMFLAG 0 will function correctly FEKO User s Manual 8 82 DESCRIPTION OF THE GEOMETRY CARDS PONOCOUPL 0 usual option coupling between MoM and PO is considered 1 The coupling between the MoM region and the PO region is neglected The implication is that the currents in the PO region has no effect on the current distribution in the MoM region This option which should lead to some saving in computational time and storage space is especially useful when the PO region and the MoM is not directly adjacent POMAXREFL This parameter determines the number of reflections to be taken into account for triangles with labels in the specified range For example POMAXREFL must be at least 2 to calculate the scattering from a dihedral and at least 3 for a trihedral R3 If Rg is empty the PO is applied to all triangles with label PO LAB If Ra is set the PO is applied to all triangles with labels in the range from POLAB to Rs both end values included R4 The ray tracing required for the physical optics is accelerated by recursively subdividing the problem domain a so called multilevel tree It must balance memory requirement against speedup
371. smaller than where A is the free space wavelength 10 gt e The area A of each triangular element should be smaller than 45 For an equilateral triangle with side length s the area is given by A v3 owe Using Ha formula it is found that the edge length s should be shorter than obrante gt According to the geometry and the need for accuracy more or less triangles may be needed If the memory constraints allow it a segment length of 9 is preferred e When modelling a surface by means of a wire grid the radius should be chosen so that the wire area in one direction is approximately the same as the area of the surface to be modelled as a wire grid From the approximation 2rr 1 1 one finds the wire radius to be i rx 277 where defines the segment length December 2002 FEKO User s Manual 8 48 DESCRIPTION OF THE GEOMETRY CARDS e The length on dielectric cuboids has to be small in comparison with the wavelength A in the dielectric as well as the skin depth Er E WUT e In some cases accurate modelling of the geometry requires significantly finer trian gles and segments than specified by thie guidelines above For low frequencies in particular the segmentation rule of 2 7p is often much too coarse to yield a reason able representation of the geometry Another case where finer discretisation may be required is where a wire runs parallel to a conducting plate If the wire is closer than to the plat
372. specified in bytes but in terms of the number of type DOUBLE COMPLEX numbers These require 16 bytes each For example 400 MByte is specified by set ting nmat 400 1024 1024 16 The same effect can be achieved by setting the variable maxalloc such that it is unusual to assign a value to nmat npuf The maximum number of control cards that may occur in a loop for example in a frequency sweep 2 7 Environment variables This section lists the environment variables that may be used to control the execution of FEKO See also the discussion of the installation the script initfeko or the batch file initfeko bat in the Getting Started manual This script and batch file is usually automatically created by the FEKO installation program and the environment variables are set correctly Therefore the user does not need to set environment variables manually The following environment variables may be set FEKO Must be set to the path where the FEKO executables are located which normally is FEKO_HOME bin December 2002 FEKO User s Manual 2 16 GENERAL COMMENTS FEKO_CMDINFO If this environment variable is set to the value 1 FEKO writes additional data concerning the number and the value of the received command line parameters to the screen This can be useful to trace errors in the parallel version of FEKO used in connection with some implementations of mpirun mpiopt mpprun etc FEKO_LITE If this environment variable is set to
373. t of this layer in the principal direc tion R The loss factor tand tand 27 of this layer in the orthogonal direction Rg The relative dielectric constant e of this layer in the orthogonal di rection EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 91 Having both triangles and segments with the label J should be avoided Separate labels and a distinct SK card for each label should be used In addition all wires with the label J must have the same radius If this is not the case a unique label must be introduced for each radius The application of the card depends on the value of Jz It should be noted that the skin depth is given by skin E where the radial frequency w 27 f and the permeability H HrHo e 5 0 No further parameters e 1 high frequency skin effect approximation The required parameters are y tan and g and for surfaces also the thickness d A good conductivity is required i e o gt wey For wires a further condition requires that skin lt o where 0 is the wire radius 1 jop in et Pa The surface impedance is given by Z Ing For metallic surfaces the condition dspin lt g must be met The surface impedance is given by Zs 4 y EL e 2 ohmic losses The required parameters are ur tan and g and for surfaces also the thickness d A good conductivity is required i e o gt w o For wires a further con
374. t If the mouse is clicked anywhere inside the list area the text in the input field is replaced by the item under the cursor This highlights as the mouse moves over it The lt Enter gt key replaces the input field by the currently highlighted item The list of suggestions may be closed by pressing the lt Esc gt key or clicking outside it If the list is longer than 10 lines it may be scrolled using the scroll bar or by clicking on an item and moving the mouse down or up outside the list border while keeping the mouse down Releasing the mouse button places the current item in the input field 4 2 3 Variable editor The button on the top left corner of the button panel launches the card editor to edit variables This is useful as it presents a list of functions and operations understood by FEKO and calculates the value of the variable as it would be evaluated by PREFEKO at this point Note that EditFEKO does not expand FOR loops Thus variables depending on other variables defined inside FOR loops will not be evaluated correctly The functions variables or operations may be selected from the three drop down boxes and a special group for the FILEREAD function The selected item is automatically placed at the current cursor position Note that variables and functions are highlighted after insertion but operations are not If a function is selected while some part of the variable string is selected the selected text will be ins
375. t It should be remembered that it is not possible to specify a wire radius in FEMAP Thus the wire radius must be specified by an IP card preceding the IN card Simi larly when specifying the surface of a dielectric the IN card must be preceded with the correct ME card completely analogous to the case without FEMAP The following illustrates the use of the IN card to include FEMAP neutral files Set wire radius IP Include a metallic structure all structures in the model IN 1 phone neu December 2002 FEKO User s Manual DESCRIPTION OF THE GEOMETRY CARDS Translate or rotate the above geometries TG Include an additional dielectric structure only layers 3 to 5 ME 1 0 IN 1 head neu 3 5 Some additional geometric data DP A DP B ssa BL A B WinFEKO should be used to verify the included geometry FLAG 2 Read geometry from an ASCII data file With the syntax IN 2 part_1 dat IN 2 part_2 dat 5 IN 2 7 part_3 dat 7 10 scaling 0 1 the IN card reads the geometry data from a data file whose structure is described below Both label and type selection and scaling are supported The type selection parameter x may have the following values Wire segments Surface triangles Polygonal plates o e N Tetrahedral volume elements Dielectric triangles or metallic triangles which form the surface of a dielectric are created by preceding the IN card with the appropriate ME card In exactly the s
376. t The maximum number of points considered for the near field com putation with the FE card when FELKOR 6 irregular separately specified field points The maximum number of areas that are described by using the Fock theory The maximum number of entries in the interpolation tables for the Green s function of a planar substrate The maximum number of HA cards used internally to set up micro strip ports that may be present in the fek file The maximum number of internal edges also the number of basis functions per triangle It may be larger than 3 if more than two plates share an edge The maximum number of nodes that may lie against a segment The maximum number of L4 type loads The maximum number of labels The maximum number of LE cards which specify a load on an edge between triangles The maximum number of edges between two surface triangles that can be loaded with a single LE card Dimension of the interpolation table used for the planar multilayer Green s functions This variable determines the maximum number of sample points in the z direction The maximum number of different media used for the treatment of dielectric bodies in the surface equivalence principle The surround ing free space medium 0 is not counted i e with maxmedia 1 one dielectric body can be treated The maximum number of triangles The maximum number of edges between two triangles The maximum number of edges in the physical opti
377. t there are N sources such as in an array antenna with open circuit voltages Up before the scaling operation where the parameter v lies in the range 1 N At each source there is an antenna input impedance Za as calculated during the FEKO solution to which power Pa is transferred EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 87 e PWFLAG 1 When PWFLAG 1 all the source power is delivered to the respective antennas i e Pro Pav as shown in figure 9 29 Thus the total power can be scaled to Py with the factor M E N N 2o Pow S Pov The currents on the structure are scaled with the factor y s There is no power loss e PWFLAG 2 When PWFLAG 2 the internal impedance Z of the voltage source is considered as shown in figure 9 29 Since the same current flows through the internal source impedance and the antenna input impedance the power dissipated in the impedance of the v voltage source is given by the relation Re Zi Piv Pay ReZav and the scaling factor s to scale the total power supplied by the sources to Pp is Po Po Po F Os Pav 1 PX Mz Mz Poy Pay Piv al v 1 v Mz v 1 The combined loss caused by the mismatched antennas oul E Re Zi Poss 8 2 Paw S Pow eaa reduces for example the antenna gain but not the directivity e PWFLAG 3 When PWFLAG 3 each antenna with input impedance Za is considered to be excited by
378. t SAR The SAR will be calculated as discussed in section 3 5 5 9 Maximum SAR calculation options do NOT have an effect on ortho slice contour or grid displays of the near fields See section 3 5 5 9 for a discussion on Mazimum SAR calculations using iso surface Hit the Back button to return to the main Near field options panel The ortho slices and model geometry can be made visible invisible by selecting unse lecting the Ortho slices and Geometry options in the Main display options panel 3 5 5 11 Near fields Animation For vector arrow and colour ortho slice plots of near fields animation is available First select and plot the required ortho slice scaling etc see 3 5 5 10 With instantaneous selected under Component the Animation button on the Near field option panel will become active Click the Animation button The Animation control panel is activated This is a modal panel and the Close button must be clicked before control is given back to the main WinFEKO window Decide on the animation format by selecting either Gif or Bmp under the Format option Gif Animation Gif animation takes longer to prepare but uses less resources memory than Bmp animation Animated gifs can be saved to be viewed in most browsers and some viewers With Gif animation the number of steps speed and continuous or not continuous settings must be decided on before preparing the animation Bmp Animation The preparation of Bmp animatio
379. t direction is defined from the segment ISEGP to the segment ISEGM The column KNOP indicates whether the begin point KNOP 1 of the segment ISEGP connects to the node or if it is the end point KNOP 2 The following four columns contain the data about the symmetry and are the same as for the metallic triangles described above If there are any connections between triangles and segment then the following data is given GEOMETRIC DATA OF CONNECTIONS SEGMENTS TRIANGLES Data of triang data of segm info of symmetry no DRENUM DREPOI SEGNUM SEGPOI angle yz XZ xy status 1 11 1 360 0000 0 0 O unknown 15 1 45 0000 33 1 45 0000 55 1 45 0000 Each connection point is assigned a consecutive number which is given in the first column The number of the triangle at the connection point is given in the column DRENUM with the connecting vertex 1 to 3 in the column DREPOT Likewise the connecting segment s number is given in the column SEGNUM and the connecting end in the SEGPOI column If the begin point of the segment is connected SEGPOI 1 else the end point is connected and SEGPOI 2 The column angle gives the angle that is formed by the triangle at the connection point in radians The meaning of the symmetry information in the last four columns is the same as that of the metallic triangles given above EM Software 4 Systems S A Pty Ltd December 2002 DESCRIPTION OF THE OUTPUT FILE OF FEKO 14 5 If a dielectric volume element has been
380. t may also be negative The aim function is now defined as Ng Ng Ng i 1 j 1 i 1 j 1 Example NEARFIELD xk E field H field T 10 1 1 0 10 1 376 73 Near field values This aim function enables one to optimise either the electric or the magnetic near field or both with respect to certain defined field strength values Since the absolute field strength is just scaling linear with the amplitude of the excitation this extra degree of freedom is removed by supplying a normalisation of the near fields with respect to one point whose amplitude after normalisation will then be one and then phase will be zero The optimisation parameters follow the keyword NAHFELD_WERTE or NEARFIELD_VALUES If only the electric or the magnetic near field is to be optimised to have a certain shape then the line following this keyword contains the parameters M Np Ng Nnorm Neomp fi fo f3 M is a flag and has the following meaning M 1 Use the electric near field 2 Use the magnetic near field Np gives the number of blocks containing electric or magnetic near field strength values to be read and Ng gives the number of lines to be read from each of these blocks The value Nnorm must be in the range 1 Ng Ns and indicates which field strength value shall be used for the normalisation Each field strength vector either electric E or magnetic H has three components E1 Ez Ez or H H2 H3 respectively For instance in a Cartesian coordinate system the ass
381. tch illustrating the use of the WG card Parameters S Name of the first corner point of the parallelogram S2 Name of the second corner point of the parallelogram S3 Name of the third corner point of the parallelogram S4 Name of the fourth corner point of the parallelogram R 0 Only the wires inside the parallelogram are generated 1 All the wires are generated This option is important when two adjacent parallelograms are generated because the sides must then not be generated twice R The maximum segment length is given by the IP card The parameter Ra is an integer number and represents the length of the gaps in the wire grid For Ro 1 the gaps are one segment in length for Ra 2 two segments etc EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 107 Example of WG card usage Using the following commands the wire grid seen in figure 8 60 is generated IP 0 02 0 2 DP A 0 0 0 0 0 0 DP B 0 0 0 0 1 2 DP C 1 2 0 0 1 2 DP D AD 0 0 0 0 WG A B C D 1 1 EG EN TE NOS o A MS CA A ee Ma MM A cod C D L D a a A e i Li A HH Figure 8 60 First example for the WG card December 2002 FEKO User s Manual 8 108 DESCRIPTION OF THE GEOMETRY CARDS 8 2 42 ZY Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 S S2 S3 Sa Ry Ra R3 TR ae aes INL NT REAL REAL REAL REAL REAL REAL REAL
382. te the electric vector potential F 13 Compute the gradient of the scalar magnetic potential V y Negative sign only the scattered part of the field potential no source contribution is written to the output file Positive sign The total field potential the sum of the scattered and source contibutions is written to the output file Values for FELTYP 4 5 and 6 are obsolete and should be replaced with 1 2 and 3 respectively ANZX Number of field points in x or r direction see FELKOR below For FELKOR 6 ANZX and ANZY are not used ANZY Number of field points in y y or Y direction ANZZ Number of field points in z p x or y direction For FELKOR 6 this parameter specifies the total number of points FELKOR indicates the coordinate system used in which the near field is to be calculated 0 Cartesian coordinates x y 2 Cylindrical coordinates r p z Spherical coordinates r J p Cylindrical coordinates r p x around the x axis Cylindrical coordinates r y y around the y axis Conical coordinates y z around the z axis aor W NH Irregular points in Cartesian coordinates x y z EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 55 X0 x orr coordinate dependent on FELKOR of the first observation point YO yor yor Y coordinate of the first observation point ZO z or coordinate of the first observation point DX Increment size in x
383. ted by CADFEKO These models are already meshed The syntax of the IN card is then IN 8 part_1 neu IN 8 part_2 neu 5 IN 8 7 part_3 neu 7 10 scaling 0 001 As for a number of import options label selection is allowed Also scaling is sup ported The type selection parameter x is supported and may have the following December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 45 values 1 Wire segments 2 Surface triangles 8 Tetrahedral volume elements 16 Node points If the parameter x is omitted wire segments and surface triangles are imported but node points are not Points can be imported similar to the case when importing neu files All points defined in the CADFEKO model are then available in PREFEKO as if they were defined with DP cards with the names as defined in CADFEKO This may be used for example to attaching additional structures to the geometry using PREFEKO cards Unlike the case for FEMAP and NASTRAN the coordinate values are not defined as variables If these are required the user should use the x_coord y_coord and z_coord functions WinFEKO should be used to verify the included geometry e FLAG 9 Read geometry from a PATRAN file PREFEKO also supports importing PATRAN files Only the following PATRAN neutral packet types are imported 01 Node data all coordinates are interpreted in the global rectangular frame local coordinate frames are not supported 02 Element data The shapes 2 bar 3 tri 4
384. tems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 39 9 2 16 AV Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 INT INT INT INT INT STR STR STR STR STR With this two line card an impressed current source is specified similar to that of the Al card but with the AV card the end point makes electrical contact with a conducting surface as shown in figure 9 16 The current varies linearly between the value at the start point and that at the end point At the connection point special singular functions are used for the surface current density on the triangles to allow continuous current flow J metallic 2 triangles pa N Figure 9 16 Impressed line current with a linear current distribution and electrical contact to conducting triangles Parameters ANFL o New excitation replaces all previous excitations 1 Additional excitation add to previous excitations ULA 0 The coordinates of the end point 7 are known and specified with EIR32 EIR4_2 and EIR5_2 This point must coincide with a corner point of one or more triangles 1 The coordinates of the end point r2 are not known In this case the input fields EIR3_2 EIR42 and EIR5 2 are not used FEKO searches through all the metallic triangles for the corner point that is closest to the start point 7 of the current element This is then the end point Fa For both ULA 0 or ULA 1 FEKO automatically searches for all the triangles maki
385. tes of the corner points of the polygonal plates e Coordinates radii and dimensions of UTD cylinders EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 89 Coordinates of the corner points of tetrahedral volume elements Thickness of dielectric surface elements SK card section 9 2 38 Radius and thickness of a wire coating CO card section 9 2 20 Coordinates of wedges and edges in the PO region Coordinates of the Fock region Transmission line length and end point coordinates TL card section 9 2 40 The dimensions of the aperture used in the AP card and the amplitudes of the A5 and A6 dipoles which depend on the incremental areas The variable EPSENT specified with the EG card section 8 2 12 which controls whether two points are considered to lie at the same point is space In the mode SKALFLAG 1 all geometrical dimensions and coordinates are scaled This includes in addition to the parameters listed above the following The coordinates of the source point specified in the excitation cards Al A2 A3 A4 A5 A6 A7 if the selection is not made by label Coordinates of the origin of the radiation pattern specified with the AR card Coordinates of the start and end points of the impressed currents for the AI and AV source cards as well as the wire radius specified with these cards Radii of the coaxial feed in the A3 card Radius of the approximated connecting segment in the A4 an
386. tesian coordinates R1 R and Rs in a second line immediately following the TL card These coordiantes must be at the centre of a wire segment Label of the segment which represents the end of the transmis sion line If more than one segment with this label exists then the last segment with this label is used In the special case I3 1 the end point of the transmission line is defined by specifying its Cartesian coordinates R4 R and R in a sec ond line immediately following the TL card These coordiantes must be at the centre of a wire segment The positive port voltage definition is according to the direction of the segment that it is connected to from the start to the end point of the segment Thus the input and output ports of the transmission line have unique orientations For I 0 or empty the transmission line connecting the ports is not crossed for 4 1 it is crossed The length of the transmission line in metres In the special case R 1 FEKO determines the length based on the geo metrical distance between the start and end points Ry is scaled with the scaling factor of the SF card December 2002 DESCRIPTION OF THE CONTROL CARDS 9 95 Ra Real part of the characteristic impedance of the transmission line in Ohm R3 Imaginary part of the characteristic impedance of the trans mission line in Ohm Note that the characteristic impedance only defines the ratio between the voltage and cur
387. than one PO card may be used The parameters NOSHADE and POMAXREFL can be specified for each label but the parameters POSYMFLAG PONOCOUPL R4 and SAVEVIS are global For the global parameters the values of the last PO card will be used A basis function that has been assigned to an edge between two triangles will only be solved with the PO if the PO approximation has been declared for the labels of both triangles The metallic PO region must be perfectly conducting i e no losses are allowed December 2002 FEKO User s Manual 8 84 DESCRIPTION OF THE GEOMETRY CARDS 8 2 30 PY Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 A B Cc D E F G ma ae ae ney ae REAL REAL REAL REAL REAL REAL REAL REAL This card defines by specifying the corner points a polygonal surface to which the UTD or PO formulation is applied The UTD is applied unless the PO is specified for the label of the polygon A sketch is shown in figure 8 49 A Figure 8 49 Sketch illustrating the use of the PY card Parameters A Name of the first corner point of the polygon B Name of the second corner point of the polygon etc A maximum of 26 corner points are allowed The points are connected in the order in which they are entered in the PY card The corner points have to be defined prior to the PY card by a DP card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 85 Example of PY card usage The commands
388. the U U H Hy components U Es Ey E se the Hy Hy H QO 0 gt 0 N e se the H H components The magnitude of the field strength is evaluated in each case Ng gives the number of blocks containing electric or magnetic near field strength values to read and Ng gives the number of lines to read from each of these blocks For this case the aim function Z is defined as i Ne Ns I N Ne pr 2 Es y using the magnetic near field A when M is 4 5 or 6 The negative sign ensures that a minimisation of the aim function maximises the near field Example NEARFIELD 3 10 1 If a linear combination of the electric and magnetic fields must be maximised it can be minimised by using negative factors the keyword NAHFELD or NEARFIELD is followed by the parameters M NE N FF NE NE and F in this order The flag M is similar to the previous case 7 Use the E Hy E H E H components M 4 8 Use the E Hy E H Ey Hy components 9 Use the E H E H E H components As before only the magnitude of the field strength is evaluated in each case N gives the number of electric near field blocks to read and N ES the number of lines to read from each of these blocks Similarly N a gives the number of magnetic near field blocks and N E the number of lines for each block December 2002 FEKO User s Manual 10 12 THE OPTIMISER OPTFEKO The parameters F and F are arbitrary proportionality constants tha
389. the coil s axis S3 Name of the begin point of the windings Sa 0 Create connections from the two ends of the coil to the axis at points S and S2 See also left side of figure 8 21 1 The connections are not generated this means that the point S3 is a connection point See also the right side of figure 8 21 Ri Amount of windings If negative a left handed coil is created R Maximum length of the segments that are used for the windings in m is scaled by the SF card If this parameter is left empty the value specified with the IP card is used R Normally the wire radius is set with the IP card Setting R3 overrides this radius for the current helix without affecting the default for later segments Rg is in m and is affected by the SF card scaling factor December 2002 FEKO User s Manual 8 30 DESCRIPTION OF THE GEOMETRY CARDS Ra A helix with a tapered radius can be created by setting both R3 which then specifies the radius at the start point 51 and R4 which specifies the radius at the end point S2 The segments connecting to the axis see S4 are not tapered and have radii Rg and R4 respectively Rs If this parameter is empty or is set to 1 a helix with a circular cross section is created Setting Rs allows within reasonable limits gen erating a helix with an elliptical cross section R5 2 gives the ratio of the ellipse s two half axes where a is the distance 51 83 Quite often modelling the geometry of the c
390. the convergence criteria If the basis of the Simplex is smaller than this value then the optimisation is stopped The fourth parameter is also a convergence criteria If the standard deviation of the values of the aim function in the corner points of the Simplex is smaller than this value then the optimisation is also stopped Example SIMPLEX_METHOD 0 15 0 5 0 001 0 001 The simplex method by Nelder Mead This method is similar to the above mentioned method but it is implemented according to the Nelder Mead variation In this case seven parameters are specified after the keyword SIMPLEXVERFAHREN or SIMPLEX_METHOD The first indicates the basis of the Simplex in the normalised space If the Simplex starts rotating around a minimum its basis will be scaled down by the factor given by the second parameter The third parameter is the convergence criterion If the basis of the Simplex is smaller than this value then the optimisation is stopped The fourth parameter is also a convergence criterion If the standard deviation of the values of the aim function in the corner points of the Simplex is smaller than this value then the optimisation is also stopped The last three parameters represent reflection contraction and expansion With contrac tion the Simplex is changed similar to reflection but becomes either smaller negative contraction or somewhat larger positive contraction than its original size Contraction is executed when norma
391. the excitation output The keyword ANREGUNG EXCITATION indicates whether the time variation of the excit ing pulse is to appear in the output file Example Output the excitation pulse EXCITATION 11 3 5 Definition of a time point With the keyword ZEITPUNKTE POINTS_IN_TIME the near fields surface currents and line currents can be calculated at certain points in time Using time points has no effect on the calculation of source currents or far fields If normalisation has been set NORM then the time points must also be given in normalised form y Example Specifying the time points time has been normalised POINTS_IN_TIME 5 0 10 0 15 0 20 0 December 2002 FEKO User s Manual 11 8 THE PROGRAM TIMEFEKO 11 4 Running TIMEFEKO Firstly the input files pre and tim have to be created During execution new input files pre are continuously generated by adding the string _tim_ and a sequentially incremented number to the file name If for example the input files cube pre and cube tim have been created TIMEFEKO is executed with the command timefeko cube On the command line the following parameters can be added a Here an FFT is only performed on the already available data r The pre and out files are deleted after each iteration This saves disk space np x If this option is given the parallel version of FEKO if it is avail able in the installation is used in the solution The parameter x specifies
392. the following data file 5 3 0 0 3 0 0 0 1 0 4 0 2 0 1 0 2 5 3 0 2 5 0 0 3 0 4 0 1 0 0 0 3 0 1 2 3 0 7 1 3 5 0 7 3 4 5 0 7 FLAG 3 Read geometry from a NASTRAN file PREFEKO supports importing column based NASTRAN files Only the keywords GRID CTRIA3 CQUAD4 CBAR CROD and CTETRA for nodes triangles quadrangles divided into two triangles along the shortest diagonal segments and tetrahedral volume elements are processed All other keywords are ignored In this case the syntax is IN 3 part_i nas IN 3 part_2 nas 5 IN 3 35 part_3 nas 7 10 scaling 25 4 The label selection uses the NASTRAN properties which are converted to FEKO labels Note that scaling is supported EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 37 A 1 3 0 1 P4 P2 4 2 1 y P3 2 5 3 2 5 P4 0 3 4 P5 1 0 3 P2 Figure 8 22 Example for IN card The type selection parameter x is supported and may have the following values 1 Wire segments 2 Surface triangles 16 Points 32 Quadrangles divided into triangles 64 Points but only those used by the imported geometry As when importing neu files the wire radius must be set with the IP card preced ing the IN card and an ME card must be used when specifying dielectric surfaces in the same way as when the IN card is not present The user can also import points from the NASTRAN file similar to importing points
393. the near field calculated for each frequency the input file may look as follows AG aua Read the rsd file PEO sds k Calculate the near field EN End December 2002 FEKO User s Manual 9 22 DESCRIPTION OF THE CONTROL CARDS However if one wants to analyse for example a metal plate which is excited first by an impressed line current and then also by a plane wave in each case the near fields and the currents on the plate must be written to the output file the input file would be Excitation by a line current AC sua Read the rsd file EE sas Calculate the near field OS Qutput the currents Excitation by a plane wave ER was Set the frequency and terminate AC loop AO Specify plane wave excitation FE oa Calculate the near field OS sare Output the currents End EN EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 23 9 2 12 AE Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 I I2 I3 14 EIR1 EIR2 EIR3 IE REAL REAL REAL REAL REAL REAL REAL REAL This card specifies an excitation at an edge between triangular surface elements similar to the A7 card The AE card however has the advantage that the location of the feed point and the positive feed direction are substantially easier to specify In addition it is possible to specify a feed edge which contains a number of triangle edges as shown in figure 9 5 Label I2 LabellB _
394. the separate sources The user should remember that this is then the resulting input parameters in the active environment which is not the same as exciting the sources one by one If additional sources are added after the first calculation this represents a new environment and the original sources will be listed again Click to highlight a frequency and select a source for this frequency The corresponding Source data is displayed This information has been extracted directly from the FEKO output file P_s gives the available source power and P_m the power lost due to mismatch Under Scale the user can select a linear or logarithmic scale to use a logarithmic scale the plot parameter must remain larger than 0 or he can plot the quantity in dB If any of the quantities selected have negative values and either Log or dB scaling has been selected then a warning will be given and the graph will be plotted on a linear scale One may also elect to plot the input impedance on the Smith chart Some antenna parameters can be plotted as a function of frequency if more than one frequency solution is available To enable the Plot options select a range of frequency values in the frequency block by clicking and dragging over the required range The Zo ohm field gives the system impedance which is used for 511 and VSWR calcu lations In some cases such as when calculating coupling the source segment is loaded with the system impedance FEKO calculates an
395. the two arguments called as min ta b FMOD this function also has two arguments fmod a b and returns the remainder of the division a b RANDOM This function returns a random value in the range 0 1 If the argument X of RANDOM is 1 then a random number is returned For any other argument X in the range 0 1 this value is used to set the seed and then a random number is created using this seed Using the same seed allows one to create a deterministic and reproducible random number series If RANDOM 1 is called before any seed is set in the pre file then the returned values are random and not reproducible The internal seed is used based on the time when PREFEKO is executed X_COORD This function returns the x coordinate of a point previously defined by a DP card The name of the point in quotation marks is passed as an argument to the function for example DP PNTO1 1 234 0 4567 Hz x x_coord PNTO1 will set the parameter x equal to 1 234 Y_COORD Returns the y coordinate of a previously defined point similar to the function X_COORD discussed above ZCOORD Returns the z coordinate of a previously defined point similar to the function X_COORD discussed above The FILEREAD function reads a numerical value from an arbitrary ASCII file The general syntax is fileread Filename Line Column and contains the filename the line number to read from and the column to read The data in the respective colu
396. these toolbars are associated with menu items and their functionality will be described in the corresponding menu item section The functionality of speed buttons not associated with menu items will be discussed in more detail in this section 3 4 1 FILE control toolbar Used for WinFEKO file control and printing 1 Create a new project see section 3 5 1 1 2 Open project see section 3 5 1 2 3 Save project settings see section 3 5 1 4 4 Print the model see section 3 5 1 6 December 2002 FEKO User s Manual 3 4 THE PROGRAM WINFEKO 3 4 2 FEKO control toolbar Used for execution of FEMAP and the different FEKO modules Run FEMAP section 3 5 2 1 Run EditFEKO section 3 5 2 3 Run PREFEKO section 3 5 2 4 Display model section 3 5 2 5 23 4 b 6 7 Display field points section 3 5 6 7 Display excitation section 3 5 6 8 Run FEKO solver section 3 5 3 1 NO oT FP Ww YP KF 3 4 3 DISPLAY OPTIONS control toolbar Used to quickly go to the different model display option panels available in WinFEKO Go to Main display options panel see section 3 5 6 1 Go back to previous options panel see section 3 5 6 2 Go to FEK file display options panel see section 3 5 6 3 Go to NEU file display options panel see section 3 5 6 4 Go to Cutplane options panel see section 3 5 6 5 Go to Advanced visibility options panel see section 3 5 6 6 Go to Transformation
397. time instant value in degrees can be selected Check the Multiply data with linear scaling or Add to data dB scaling box and enter a value to scale the data as required One may for example add the negative of the maximum dB value to normalise a graph to 0 dB SAR calculations from near field data Select the More button for more near field options The only extra option applicable to iso surface displays is the SAR options Thus Transparency Lines on surface plot Contour options and Other options do NOT affect the iso surface display For SAR calculations the correct material parameters must be set Enter the medium density in the edit field The conductivity is read from the out file Note that one cannot use the old format near fields to extract SAR December 2002 FEKO User s Manual 3 18 THE PROGRAM WINFEKO The SAR will be calculated from SAR 1212 With SAR selected as near field quantity the Maximum SAR calculation options can be set Enter the weight in gram over which the maximum SAR must be averaged Select Iso Vol or Cube as the shape over which to calculate the maximum SAR With Iso Vol selected an iterative process of iso surface calculations will begin A closed iso surface with weight approximately equal to the specified value will be searched for and the SAR in volume enclosed by this iso surface will be calculated The maximum SAR as averaged over any continuous volume of appropriate size and
398. tion does not have to be resolved The user must ensure that the geometry does not change between the two calculations FEKO does not check for any differences It often happens that one for example runs a calculation on a workstation with large amounts of RAM and saves the currents in a str file Then one may use a PC with less storage space to do further calculations such as post processing FEKO will try to allocate memory for the complete system matrix out of core if required but the currents will be imported from the str file If the parameter PS2 or PS3 is set the PS card may occur only once in the input file It is advisable to place it right after the EG card EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 85 9 2 37 PW Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 PW PWN WPOWE R2 R3 LAG CPL A IE REAL REAL REAL REAL REAL REAL REAL REAL When defining the excitation of an antenna the source is normally specified as a complex voltage The PW card allows the user to specify the radiated power instead In addition it is possible to consider a mismatch between the antenna input impedance and the internal impedance of a voltage source or the characteristic impedance of a transmission line feed Parameters PWFLAG 0 PW card is not activated i e the specified value Uy of the voltage source is used 1 PW card is activated and all the currents are multiplied by a scal
399. tment of the dielectric magnetic coatings on wires or multilayer dielectric magnetic coatings on surface triangles These are e DOCOVR 1 method using Popovic s formulation In this case the radius of the metallic core is changed internally to model the change in the capacitive loading of the wire and a corresponding inductive loading is added The following restrictions apply The loss factor tan of the layer which is calculated from the conductivity o and the relation tand 27 has to be identical to the loss factor of the WEr surrounding medium specified with the EG card usually free space Due to the change in the radius of the metallic core no SK card should be active for the same label otherwise the skin effect and or the ohmic losses refers to the wire with changed radius For pure dielectric layers i e the relative permeability uy of the layer equals that of the surrounding medium the option DOCOVR 2 rather recommended DOCOVR 2 method using the volume equivalence theorem Here the radius of the metallic wire is retained The effect of the dielectric layer is accounted for by a volume polarisation current The only restriction of this method is that the layer may not be magnetic in nature i e the relative permeability ur of the coating must be the same as that of the surrounding medium EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 49 e DOCO
400. to the use of the equivalence principle AP 0 3 Pi P2 P3 1 5 3 2 0 0 0 Guide dat which will generate nine x directed magnetic dipoles of the correct magnitude in the fek file December 2002 FEKO User s Manual 9 34 DESCRIPTION OF THE CONTROL CARDS 9 2 15 AR Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 NFU Ig 13 I4 Is Ri Ra R3 Ra Rs Re R7 Rg A IE REAL REAL REAL REAL REAL REAL REAL REAL With this card the radiation pattern of an antenna is used as an impressed source The pattern is read from a data file or defined in the pre file below the AR card This card has a variety of uses for example importing measured radiation patterns synthesising arrays from the individual patterns of the elements realising radiation only within certain sectors etc In the MoM UTD hybrid it is possible to simulate for exam ple the antenna on its own and to save the far field in a ffe file This field is then imported and used as source in the UTD part which may greatly speed up the ray tracing computation as there is now only one source point Parameters ANFL 0 New excitation replaces all previous excitations 1 Additional excitation add to previous excitations Iz 1 Read the radiation pattern from an ffe format file which may be created with the DA and FF cards 2 Read the radiation pattern from an ASCII file the format of this file is described below 3 The radiation pattern is specified in the J4 5 lines fo
401. traction panel uses the same templates as from the Network parameters panel If the user selects Save template while the panel from which the graph was created is still open GraphFEKO will suggest the correct template name If not the user has to December 2002 FEKO User s Manual 5 4 THE PROGRAM GRAPHFEKO specify the type of graph by selecting the appropriate options The templates are saved in the directory specified by the environment variable FEKO_USER_HOME If a new graph is created with GraphFEKO and the appropriate template file is not available GraphFEKO will use internal defaults for the graph 5 3 1 8 Load data Use this command to plot data from a text file It can be added to the current graph or a new graph can be created The data must be in columns separated by one or more spaces no commas The data in the second and higher columns are plotted against the first column The table below shows an example of a text file with data for two lines ready for import into GraphFEKO The first line consists of the x axis caption associated with the first column followed by a legend for each of the remaining data columns Note that the captions must be in the first row and each caption must be between quo tation marks If no caption row is present GraphFEKO will still import the data first column on the x axis subsequent columns on the y axis If any column except for the first column does not have the same number of data en
402. tries as the first column the empty data points must be represented by the text NAN Frequency MHz mag S_11 mag S_21 1 00000E 02 4 74462E 01 2 83472E 01 2 00000E 02 1 46055E 00 2 66604E 01 3 00000E 02 7 46769E 00 2 06073E 01 4 00000E 02 2 19462E 00 NAN 5 00000E 02 6 12814E 00 NAN After selecting Load data a Data import options window is opened By default a new graph window will be created The data can also be imported onto the current active graph window by selecting On current Ensure that the correct graph window is active before selecting Load data For a new graph the user can also select between polar or line graphs For polar graphs the first column specifies the angle in degrees For Smith chart data the first column must contain the phase in degrees and the next columns the amplitude 5 3 1 9 Save data Export the data associated with the active graph window to a text based data file using the Save data option The data will be saved in the GraphFEKO column format described in the previous section Only the visible lines will be exported and a maximum of ten lines 11 columns in total can be exported EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM GRAPHFEKO 5 5 5 3 1 10 Print The Print option invokes the GraphFEKO printing preview window The user can specify the margins and page orientation Changing the Detail setting towards More reduces the font size of all text and thus incre
403. trol cards 9 1 Overview of control cards and remarks on execution sequence The following table summarises all the PREFEKO and FEKO control cards These cards should not be used in the geometry section of the pre input file i e they should only be used below the EG card The control cards are used to specify for example the frequency and the type of excitation They also determine the required calculations such as the locations for near field calculations and the directions for far fields calculations etc Card Description characters used to indicate a comment line Ax type of excitation e g an incident plane wave or a voltage source BO through the use of the reflection factor coefficient a ground plane can be inserted CG the algorithm used to solve the matrix equation is selected CM Field calculation for CableMod coupling into transmission lines CO inserts a dielectric and or magnetic surface on the elements DA creates additional files for the results DI enters the properties of the dielectric when using the surface current method EN indicates the end of the input file FE calculates the near fields FF calculates the far fields FR sets the frequencies at which the calculations are to be carried out GF sets the Greens functions L4 add a load between a metallic triangle and the ground plane for the planar multilayer Greens function LD defines a distributed series circuit load consisting of
404. tromagnetic force of the impressed voltage source is in the opposite direction It should be noted that the edge between the surfaces with labels Jz and 3 for I4 0 does not have to be straight One may for example excite two half cylinders against each other If an impedance must also be applied to the edge the AE card can be combined with the LE card For J 0 more than two triangles may be connected to each edge section as shown in figure 9 6 However one of these triangles must have a unique label and all the other triangles connected to this edge must have the same label In figure 9 6 there is one triangle with label 2 at each edge between triangles and all the others have label 1 One may therefore specify an edge between labels 1 and 2 The edge in figure 9 7 cannot be used as a feed edge as there are more than one triangle of each of the two labels involved The edge shown in figure 9 8 cannot be used as a feed edge either as there are triangles with three different labels connected to each edge Correct feed edge Figure 9 6 Example of a feed edge where more than two triangles are connected X Wrong feed edge Wrong feed edge Figure 9 7 Disallowed feed edge there is Figure 9 8 Disallowed feed edge triangles no triangle with a unique label at the edge with three different labels join at the edge EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 25 9 2 13 AI Card
405. try Plane x 0 declared as electric plane 198 2 56 MByte 8 9 of symmetry plane y 0 as magnetic plane of symmetry and plane z 0 as geometric plane of symmetry This example has relatively few unknowns Most of the computational time is therefore used to determine the matrix elements in comparison to the time taken to solve the matrix equation For applications with more unknowns the reduction of unknowns could make a considerable difference in the time and memory required December 2002 FEKO User s Manual 2 10 GENERAL COMMENTS 2 4 5 Special enforcement of symmetry Even odd method The table in the previous section demonstrates the advantage of using electric and or magnetic symmetry For very large structures which have only geometrical symmetry it may be worthwhile to consider two separate problems with electrical and magnetic symmetry as described below a Figure 2 10 Separating a problem with geometrical symmetry into two problems with electric and magnetic symmetry respectively Figure 2 10 a shows the original problem It consists of a dipole antenna with a passive wire below it This is admittedly a very simple problem normally this procedure would only be applied to much more complex structures The structure in figure 2 10 is symmetric about the plane z 0 but the excitation is asymmetric and thus only geometric symmetry can be applied in FEKO This problem may be separated into the two sub problems s
406. tual coupling is not considered This is acceptable for sources which are relatively far away or when no accurate power values are required Since gain directivity are based on power they are then also possibly not very accurate PWPOWER The total power Po in Watt i e the total power supplied by all the voltage sources or in the case of transmission lines the total power of all forward travelling waves R For PWFLAG 2 Real part of the source impedance Z For PWFLAG 3 Real part of the characteristic impedance Zr Of the transmission line R3 For PWFLAG 2 Imaginary part of the source impedance Z For PWFLAG 3 Imaginary part of the characteristic impe dance Zz of the transmission line Details of the various possibilities with the use of the PW card are shown in figure 9 29 PWFLAG 1 PWFLAG 2 z Po Ps Z Na mn Je e lz oe A z PWFLAG 3 Transmission line Po gt with characteristic Pa Z impedance Z P eo A Figure 9 29 Possible applications of the PW card to determine the total power The options PWFLAG 2 and PWFLAG 3 are only allowed for voltage sources the A1 A2 A3 A4 A7 and AE cards For models containing other sources such as dipoles and impressed currents the option PWFLAG 1 should be used For plane waves PWFLAG must be 0 The power equations for different cases are discussed below Consider in general tha
407. ual 9 60 DESCRIPTION OF THE CONTROL CARDS e FELKOR 4 Cylindrical coordinates around the y axis r p y Zz A y Figure 9 22 Field calculation in the near field FELKOR 4 Observation Point r cosy r y r sin 9 Unit vectors of the coordinate system cos yp sin p 0 f 0 0 1 sin p cos Y 0 e FELKOR 5 Conical coordinates around the z axis y 2 This option is similar to the field calculation in cylindrical coordinates around the z axis where the radius r changes with the height z A r z ro 2 20 and z lies within the range zo zo nz Az The parameters are defined in the following fields ro XO Po YO 20 ZO EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 61 Ar DX Ap DY Az DZ np ANZX ny ANZY nz ANZZ It should be noted that n ANZX must be 1 Observation Point ro 22 2 20 cosy r ro 22 z 20 sing z COS P sin p 0 r sng p cos Y z 0 0 1 Z A z x y Figure 9 23 Field calculation in the near field FELKOR 5 December 2002 FEKO User s Manual 9 62 DESCRIPTION OF THE CONTROL CARDS e FELKOR 6 irregular points in Cartesian coordinates This option allows computation of the near fields at arbitrary points defined in Cartesian coordinates If this is the case only the following parameters of the FE card are of any significance FELTYP as described above ANZZ th
408. ual Select User s manual item under Help to load the FEKO User s Manual in the PDF viewer associated with pdf files on your system If nothing happens when this item is selected then an Acrobat Reader has probably not been installed on your system The Acrobat Reader can be installed from the FEKO CD 5 3 7 2 About GraphFEKO Select this item to get the GraphFEKO version number and development information December 2002 FEKO User s Manual THE PREPROCESSOR PREFEKO 6 1 6 The preprocessor PREFEKO 6 1 Description The surface of the structure to be analysed with the program FEKO has to be subdi vided into elementary surfaces in this case triangles Wires have to be subdivided into segments The mesh size is dependent on the wavelength in the medium surrounding the structure The program PREFEKO can do all the meshing It automatically generates the geometric data in the form required by FEKO from the data given by the user The mesh density is controlled by a couple of parameters This section describe the principle workings of the program The user first defines the location of points in space with the DP card Structures are then defined in terms of these points For example two points may be joined to form a line BL card or four points for a parallelogram BP card 6 2 Running PREFEKO If for example a file example pre has been created using a text editor PREFEKO is started using the following command prefeko examp
409. ul with large models Lead lines Add lead lines to entity numbers when Element Info is selected Legend Display a legend The type of legend that will be displayed depends on other selections e g with surface and segment currents loaded a legend associated with the colour coding will be displayed Node labels When selected the FEKO DP card node labels will be displayed Normal vectors Normal vectors associated with triangular and polygonal element directions will be displayed The direction of the normal vector is defined according to the right hand rule Under Display the following options are available Geometry When selected the geometry associated with the current project fek or neu files is displayed if the geometric data has already been loaded Unselect this option to hide not delete the model geometry display Excitation When selected the excitation associated with the model is displayed if the geometric data has already been loaded Unselect this option to hide not delete the excitation display Currents When selected the segment and surface currents obtained from the FEKO output file are displayed if the current data has already been loaded Unselect this option to hide not delete the segment and surface currents display 3D patterns When selected the 3D far field patterns obtained from the FEKO output file are displayed if the far field data has already been loaded Unselect this option to hide
410. ular elements Figure 8 4 shows a sketch S S Figure 8 4 Sketch illustrating the use of the BP card Parameters S Name of the first point of the parallelogram S2 Name of the second point of the parallelogram S3 Name of the third point of the parallelogram S4 Name of the fourth point of the parallelogram R Normally a parallelogram is segmented according to the edge length specified with the IP card In some cases e g when creating small microstrip lines it may be desirable to use a finer segmentation in one direction If set R specifies the maximum edge length of the triangle elements along the edges S S2 and S3 S4 they have the same length Ri Similar to Ri but applies to the edges S2 S3 and S4 5 The points that have been previously defined in the DP card are connected in the order in which they appear in the BP card Thus the user has to ensure that the points describe EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE GEOMETRY CARDS 8 7 a parallelogram If this is not the case then PREFEKO will abort with the appropriate error message The BQ card is used to generate quadrangles The direction of the normal vector A of the subdivided triangles is determined by the right hand rule through all the corners This direction only has meaning when used with the Physical Optics PO card section 8 2 29 or with dielectrics ME card section 8 2 24 Example of BP card usage Thr
411. umber Time in 1m 0000000e 000 0916097e 001 1832194e 001 2748292e 001 2366439e 000 5458049e 000 8549658e 000 PrRPrPODWO oo0ooooo Figure 11 8 shows the response of the excitation x m 3 5 00000E 01 y m JX 00000000000e 000 00000000000e 000 00000000000e 000 00000000000e 000 00000000000e 000 00000000000e 000 00000000000e 000 the back scattered electric far field Ez 1 Normalised Ez Figure 11 8 z m 5 55556E 02 2 22222E 01 JY 87039561714e 009 10165720719e 008 92248537619e 009 95306492829e 008 20307013697e 009 97321161834e 008 39083930925e 009 JZ 55875015522e 007 96750870513e 006 37781030380e 006 84072619127e 007 89929184543e 007 24837047986e 006 53916294269e 006 E t in the time domain and figure 11 9 10 12 14 Time in light metre are a 3 0 108 s71 ty 20 ns December 2002 Time response of the excitation FEiz The parameters FEKO User s Manual of the Gaussian pulse 11 14 THE PROGRAM TIMEFEKO 0 3 Etheta in V 0 3 Time in light metre Figure 11 9 Response of the back scattered far field E of the cube EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM LFFEKO 12 1 12 The program LFFEKO 12 1 Description The acronym LFFEKO is derived from low frequency FEKO LFFEKO is not a special program but rather a special execution mode of FEKO where special basis functions for metallic
412. urces for example other Hertzian dipoles in an array antenna when calculating the power radiated by the Hertzian dipole EM Software 4 Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 17 9 2 9 A6 Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 NF EII5 EIR1 EIR2 EIR3 EIR4 EIR5 EIR6 EIR7 A E REAL REAL REAL REAL REAL REAL REAL REAL This card specifies excitation by an elementary magnetic dipole Parameters ANFL 0 New excitation replaces all previous excitations E Additional excitation add to previous excitations EII5 0 Use the model of an electric ring current for the magnetic dipole loop current I enclosed surface A 1 Use the model of a magnetic current element magnetic line current Im length 1 EIR1 Absolute value of the complex amplitude T A in Am for EII5 0 or Im l in Vm for EII5 1 EIR2 Phase of the complex amplitude I A or Im 1 in degrees EIR3 x coordinate of the dipole position in m EIR4 y coordinate of the dipole position in m EIR5 z coordinate of the dipole position in m The values EIR3 EIR4 and EIR5 are scaled by the SF card if SKALFLAG 1 EIR6 Orientation of the dipole in space Angle Y in degrees from the z axis analogue to the incidence direction in figure 9 3 EIR7 Orientation of the dipole in space Angle y in degrees is the pro jection of the dipole onto the plane z 0 opposite the x axis analogue to the angle of incidence in figure 9 3 The d
413. urrent values in the triangles the columns containing the data for the segments follow For each segment a segment number is given the centroid x y and z as well as the current I Iy and J flowing in the segment cgm file In this file the number of iterations is given and the resulting residue from the iterative solving process of the matrix equation SnP file The Touchstone S parameter filename contains the number of ports in the model The extension is s1p for a l port s2p for a 2 port and so on For 10 port and larger structures the p is dropped for example s12 for a 12 port The file contains a header following the character which specifies the frequency unit the parameter type the data format and the normalising impedance for all the ports This is followed by the data lines which may be repeated for multiple frequencies l port f Sii 251 2 port f Sy 5 ZS S21 5 4S2 S12 2512 S22 L S22 3 port f S1 ZS 5 S12 1513 S13 2513 Sa1l 4S21 S22 2522 S23 2523 S3i 453 S3al 2532 18331 4533 4 port f S1 3 ZS 5 S12 4513 S13 2513 S14 Sia Sail 4S21 S22 2522 S23 2523 S24 ZS24 Sal 2531 S32 ZS32 S33 2533 S3a 2 534 Sai 2541 Sa 2542 Sazl 2543 Saa L Sas where S11 is the absolute value and 2 51 the phase in degrees of the given parameter Note that the 2 port file is formatted on a single line and in a different order tha
414. user to select the n OS card for the given frequency and incident direction The Segments field then shows the segments available in that current block The Labels list is included for future use and is not active at present Click and highlight a frequency and select an incident angle and a single output segment The current on the segment is displayed under parameter data EM Software amp Systems S A Pty Ltd December 2002 THE PROGRAM GRAPHFEKO 5 11 Under Scale the user can select a linear or logarithmic scale to use a logarithmic scale the plot parameter must remain larger than 0 or he can plot the quantity in dB If any of the quantities selected have negative values and either Log or dB scaling has been selected then a warning will be given and the graph will be plotted on a linear scale As before the New graph button plots the frequency or incident field dependent data for the quantities selected on a new graph the Add to graph button sends data for the selected quantities to the active graph window and the Cancel button closes the Antenna reception panel and activates the Main graph settings panel Induced current as a function of frequency The antenna reception data induced current Jz in a segment can be plotted as a function of frequency if more than one frequency solution are available Select multiple frequencies by clicking and dragging with the mouse in the Frequency list Now select the Scale and what to p
415. values appear in the same order as they would be in the output file lezij Phase e1 lez phase e2 lez phase e3 In the line Nnorm of this table the component Neomp which we are normalising to must be 1 in amplitude and 0 in phase So far only the case for the electric field has been discussed normalisation aim function specification of values in the opt file but the case of the magnetic field is analogous one must just replace E by H and e by h in the formulas above Example Assume that one wants to optimise the electric near field along a line to have a quadratic shape 1 2 2j over 5 evenly spaced points in the range 0 5m lt x lt 0 5m then the normalised field strength values are 0 5 0 875 1 0 875 0 5 We assume that only the z component of the electric field is required to follow this shape we don t care about the E and E components but see comment below of how to enforce them to be zero for instance Also the phase for all 5 points should be the same then 0 because for the point no 3 that we use for normalisation it has to be 0 In the pre file the FE card would look like FE 1 5 ae 1 0 0 5 0 0 0 25 and in the opt file one would have the block December 2002 FEKO User s Manual 10 14 THE OPTIMISER OPTFEKO Near field value optimisation the first line after the keyword has the syntax M NB NS Nnorm Ncomp fx fy fz and then follow NB NS lines with the syntax ex
416. w are a number of definitions that are used frequently in this manual Segment A short section of a wire short in comparison with the wavelength Node The point where two segments are joined is called a node One basis function is assigned to each node Edge The common line between two adjacent triangles If the surface is a metal then one basis function is assigned to each edge If the surface is a dielectric then two basis functions are assigned for the current density one for the equivalent electric current density and one for the equivalent magnetic current density Connection point A connection point is where a segment is joined to a triangle The end of the segment is connected to the vertex of the triangle A basis function is assigned to each connection point Cuboid A volume element used to model dielectric and magnetic solids according to the volume current method It has 90 degree corners similar to a cube but does not have to have equal side lengths Polygon A planar surface element with straight edge boundaries The segmentation or meshing is performed automatically by the program PREFEKO but there are some rules that have to be adhered to Wires can only be connected at the end points of the respective segments They are not allowed to overlap An example is shown in figure 2 1 The wires AB and CD are not allowed to be entered in this way AB will be subdivided into segments so that point C is not recognised a
417. weight will be identified and displayed The actual weight of the identified volume and the SAR as averaged over this volume will be displayed in the read only edit boxes under Maximum SAR With Cube selected the 3D data block is scanned and the cube with specified volume and weight with maximum SAR as averaged over this cube will be identified and displayed The actual weight of the identified volume and the SAR as averaged over this cube volume will be displayed in the read only edit boxes under Maximum SAR Note To perform such a SAR calculation a uniform equal increments in all three directions Cartesian 3D grid with near field data must be available in the output file requested by the FE card for near field calculations inside a dielectric region The density of the 3D near field grid must be small enough that the SAR can be averaged over the request weight for example for a density of 1000 Kg m 1g is 1 cubic centimetre In such a case a near field grid resolution of at least 0 25cm would be required Unselect Cube AND Iso Vol to calculate and display a regular iso surface without per forming iterative SAR averaged routines Hit the Back button to return to the main Near field options panel The iso surface and model geometry can be made visible invisible by selecting unse lecting the Near fields and Geometry options in the Main display options panel 3 5 5 10 Near fields Ortho slice On selection of this item th
418. will give an error I gt 0 No execution do not read the rsd file this option is used to specify the end of the frequency loop see below 1 The line geometry frequency and currents are read from the rsd file and the line is modelled with an array of Hertzian dipoles see the A5 card The number of dipoles per line segment is specified with the parameter 3 Note that this model is only valid if the line segments do not make electrical contact with any conducting surface All the segments in the rsd file must be of the type intern and not loaded 2 The line geometry frequency and currents are read from the rsd file and the line is modelled with a continuous cur rent distribution using one AI card per line segment The AI cards are created automatically by PREFEKO when im porting the rsd file If a line segment has a loaded end point it is automatically modelled by an AV card to allow the electrical contact I In the case Iz 1 the parameter I3 specifies the number of Hertzian dipoles per line segment 10T gt use the CableMod interface this module must be activated if required please contact EMSS EM Software amp Systems S A Pty Ltd December 2002 DESCRIPTION OF THE CONTROL CARDS 9 21 I4 0 Use the discrete frequency values as they are specified in the rsd file 1 Only read the minimum and maximum frequency from the rsd file and obtain a continuous solution in this frequency band using adaptiv
419. wing is an extract from the output file cube aus TEMPORAL VARIATION OF EXCITATION NORMALISED TO U_O x y Z 0 0 0 0 0 0 Time in lm Value 0 0000000e 000 2 31952283024e 016 3 0916097e 001 8 63275340216e 015 6 1832194e 001 2 65316865993e 013 9 2748292e 001 6 73356755347e 012 1 2366439e 000 1 41120603102e 010 1 5458049e 000 2 44230818918e 009 1 8549658e 000 3 49040118194e 008 2 1641268e 000 4 11922076322e 007 2 4732878e 000 4 01439061167e 006 2 7824487e 000 3 23064343845e 005 December 2002 FEKO User s Manual 11 12 POUuNNNyR r P P 2R00yY0 THE PROGRAM TIMEFEKO VALUES OF THE SCATTERED ELECTRIC FIELD STRENGTH IN THE FAR FIELD in V THETA PHI 90 00 0 00 Time in lm 0000000e 000 0916097e 001 1832194e 001 2748292e 001 2366439e 000 5458049e 000 8549658e 000 1641268e 000 4732878e 000 7824487e 000 0916097e 000 4007707e 000 7099317e 000 0190926e 000 VALUES OF THE CURRENT DENSITY VECTOR ON TRIANGLES in A m no averaging number eer OD WO 1 5 00000E 01 Time in lm 0000000e 000 0916097e 001 1832194e 001 2748292e 001 2366439e 000 5458049e 000 8549658e 000 number eere O0OOUO 2 5 00000E 01 Time in lm 0000000e 000 0916097e 001 1832194e 001 2748292e 001 2366439e 000 5458049e 000 8549658e 000 ROHS RO P QE oO oO SO Oo 00 O ooooo cj o Factor e j BETA R R not considered ETHETA EPHI 98948137392e 005 0 00000000000e 000 17873335003e 005 0 00000000000e 0
420. wt 0 is selected With instantaneous selected under Component wt will become enabled and the required time instant value in degrees can be selected Check the Multiply data with linear scaling or Add to data dB scaling box and enter a value to scale the data as required One may for example add the negative of the maximum dB value to normalise a graph to 0 dB or scale fields to mV m Check the Fired min maz field to ensure that the minimum and maximum scaling values will NOT be changed automatically for the new data This is useful when for example ortho slices at different levels are displayed and one wants to compare these for a fixed minimum and maximum Select the More button for more near field options Use the checkbox and or slide bar to set the Transparency options applicable to the ortho slice Surface display Under Lines on surface plot select Contour for the default contour line display or Grid for a 2D grid line display Select a height slide bar to associate a height in the direction perpendicular to the ortho slice with the amplitude of the quantity December 2002 FEKO User s Manual 3 20 THE PROGRAM WINFEKO Select the number of contour lines under the Contour options The default is 20 For SAR calculations the correct material parameters must be set Enter the medium density in the edit field The conductivity is read from the out file Note that one cannot use the old format near fields to extrac
421. y 3 23 normalise model 3 5 NU card 8 67 NURBS surfaces 8 67 OF card 9 80 offset for near field calculation 9 80 ohmic losses 9 89 online help 3 33 5 21 open graph 5 1 5 2 open project 3 3 3 7 list of previous projects 3 9 OpenGL 3 1 hardware test 3 30 performance 3 30 OPTFEKO 10 1 editing files 4 6 options EditFEKO 4 2 WinFEKO general settings 3 31 toolbars 3 33 origin of rotation 3 30 ortho slices near fields 3 5 3 18 set transparency 3 18 OS card 9 81 out of core 2 12 output file 14 1 viewing 3 5 3 13 pan detail settings 3 30 speed buttons 3 5 paraboloid 8 71 parallel version running in Windows 3 12 parallelogram 8 6 parameters of segmentation 8 47 PB card 8 71 PH card 8 73 phase in GraphFEKO 5 19 phase unwrapping 5 20 physical optics 8 81 picking 3 30 1 6 planar substrate 9 67 plane wave incidence 9 8 plate with hole 8 73 PM card 8 78 PO border curved 8 14 edge 8 49 wedge 8 55 PO card 8 81 PO visibility 8 103 point names see nodes polygons 8 84 definition 2 4 display 3 25 meshed 8 78 UTD formulation 8 99 power density plotting in GraphFEKO 5 14 power input 9 85 pre files opening with WinFEKO 3 7 PREFEKO 6 1 running from WinFEKO 3 4 3 11 previous display 3 26 options 3 4 return to 3 5 PRINT command 6 9 printing 3 8 in GraphFEKO 5 1 5 5 in WinFEKO 3 3 metafile 3 9 PostScript 3 9 5 5 printer setup 3
422. y a fast backward substitution has to be done for each direction of incidence If C MSEL 0 or 5 is selected then LU decomposition is done The LU decomposition is then stored instead of the original matrix It is therefore not possible to use an iterative method to solve the matrix later without having to recalculate the elements Previous experience has shown that preconditioning always accelerates convergence It is thus suggested that calculations be done with PCFLAG 1 or PCFLAG 2 The iterative procedures using PIM CGMSEL 7 to 18 only converge satisfactorily under special circumstances The use of these techniques is not recommended and it is therefore only available in Superuser Mode of the FEKO see also SU card December 2002 FEKO User s Manual 9 46 DESCRIPTION OF THE CONTROL CARDS 9 2 19 CM Card 1 6 10 15 20 25 30 40 50 60 70 80 90 100 110 Filename INT INT INT INT INT STR STR STR STR STR This card is used to couple FEKO with the transmission line simmulation program CableMod to calculate the coupling of electromagnetic fields into transmission lines The AC card is used for the case of radiation by these lines The only parameter of this card is the file name of a rsd file created by CableMod enclosed in double quotation marks and starting at or after column 91 The rsd file contains geometry of the line With the CM card FEKO calculates the electric and magnetic near field at points along
423. y the FEKO solver if the FR card requests continuous data see section 13 Note that one may select a afo file also without a out file It opens the ADAPTFEKO results panel from which one can plot the continuous frequency data By its very nature it only allows plots as a function of frequency The Parameter field lists all the available quantities in a drop down list The quanti ties are all that are also available in the out file When the quantity is followed by sol x source y it means that this quantity was calculated as part of the xth solution and the yth source A new solution is considered each time the currents are recalculated The effect of frequency to cause a new solution is not considered here Depending on the parameter the next blocks allow the user to select what he she wants to plot For impedance and admittance the Subtract option is similar to the case for the discrete frequency data Note that subtracting 0 02 Siemens from the admittance is not the same as subtracting 50 Q from the impedance When plotting S11 or VSWR one should use impedance for voltage type sources and admittance for current type source The Number of increments field indicates the number of points used in the graphical representation the data is continuous If the Log scale option after Number of incre ments is checked the bottom axis is logarithmic and frequency points are spaced with a multiplicative constant rather than a linear spacing
424. yers named n or LAYER_n where n is an integer number in the dxf model are converted to label n in FEKO For all structures for which no label is defined in this format the label specified with the last LA card preceding the IN card is used If no such LA card is in effect the default is label 0 This label is used in the label selection As for ASCII FEMAP and NASTRAN files scaling is supported In this case the type selection parameter x may have the following values 1 Wire segments 2 Surface triangles and quadrangles Presently there is no provision to import polygonal plates or cuboidal volume el ements from dxf models As for the other CAD models dielectric triangles or metallic triangles which form the surface of a dielectric are created by preceding the IN card with the appropriate ME card PREFEKO only processes the geometry information in the section of the file be tween the keywords ENTITIES and ENDSEC Segments are imported from blocks defined by the keyword LINE 0 LINE 8 LAYER_01 10 0 0538 20 0 0 30 8 134 14 5 110 21 December 2002 FEKO User s Manual 8 40 DESCRIPTION OF THE GEOMETRY CARDS 2 857 31 0 0 next keyword The group code 8 at some point below LINE indicates that the next line contains the layer name In this case the layer will be converted to label 1 The line will be imported and segmented if this label lies in the required range If not PREFEKO will search for the next o

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