Home

EM3DS Manual

1. 28 One final note just a matter of numerical convenience greater accuracy is obtained when mesh cells align This is not a must and may be not possible to respect this rule in a complex structure but when possible it should be respected As shown in figure 27 case a where mesh cells between adjacent shapes align should be preferred Generally in order to respect this rule you have only to set the Edge Mesh Distance x in the mesh options to the same value for shapes adjacent along z and dually for adjacency along x X Working with non Manhattan polygons When clicking over Action Add Polygonal Cond a dialog box asks if the polygon has to drawn by mouse or by specifying vertices In the first case every click identifies a vertex while pressing ESC or by right clicking and selecting Close Polygon or by clicking a second time on the Polygon button the first and the last vertices are joined forming a complete polygon In the second case a dialog box let you specify the vertex co ordinates adding removing and modifying the existing co ordinates The position refers to the Top left corner but the position of the bottom right corner is automatically calculated and shown When editing modifying any general polygon a red circle highlights the point being edited You can also select in which MKS or imperial unit information is displayed The Delete Points Closer than panel allows to remove points closer than the specified distance This
2. Antenna Measurement This measurement allows to see the calculated far field if a sense layer was previously added Basically a new panel is made available Antenna Measurement Etheta sweep theta xl phi 0 deg EER mo Right a For additional menu L on F We Excite multiple ports Fort settings Fort A Voltage i Phase ZZ Deg The user can plot either Etheta E0 or Ephi Eo as function of theta and a fixed phi or of phi and a fixed theta Theta and phi are angular coordinates in spherical coordinates see details and underlying hypotheses in the antenna section Usually the antenna is excited at one port selected by the user in the To Port list while the remaining ports are shorted to ground However the user can 75 check the box Excite multiple ports and in the new panel to select for each port voltage amplitude and phase in order to plot far field of antenna arrays In this chart field is not normalized so that the user can specify the distance note no checks against meaningless distances e g not satisfying the far field requirements are performed in the present version If 0 is inserted the distance factor e r is simply replaced by 1 Custom Measurements you can create your own measurements see next section TDR Time Domain it enables the panel for the TDR Time Domain Reflectometry When selecting this checkbox the new panel is made available see the image below Seles Frequen
3. Excite multiple ports Frequency Distance e MODE Stimulus voltage Mag Update ie Yy Plot Mode rotate copy view copy into the clipboard as BMP save view to file save view to file Background color change the background color default is black modification is stored as default Displayed Quantity Choose either magnitude Real part or Imaginary part Field Component Select the polarization of the displayed field Show Axes Display reference axes Show Scale Display a scale of values Help or F1 show the help window The view may be exported to file as Windows BMP or EMF Enhanced Metafile and copied into the clipboard More views may be added and handled by he Data Browser or the main menu View XXXIX Post Processing Broadband Spice Model Extractor EM3DS includes a simple Spice Model Extractor that can be accessed by Tools Spice Model Extractor main menu or by a button in the tool Bar 88 Aid Optimizer Tuner 2D Graphs hi hata Graph Add 30 View Rendering 4dd Data Source hei Graph 3 Add Rectangular Wetwork Graph dd Smith Chart ES Smith Chart 1 Add Antenna Polar Plot Polar Plot 2 Add Sees ae 30 Graph care 4dd Current Field 3D Graph Rendering TI Polar Plot 3 4dd Contour 3D Graph z cal 4dd Mag Force 3D Graph Polar Plat 4 Add Far Field view 30 Graph rendering Add Circuit 4dd Circuit From File 4dd Broadband Spice model extractor Add Acoustic Material Definition
4. Figure 23 is very interesting as it display a fundamental characteristic in order to define Jx x at least one intermediate vertical meshing line should be defined In fact a PWS is defined so as to have its maximum in correspondence to a vertical mesh line Hence if no vertical mesh lines were defined for the displayed conductor e g because add edge mesh x is not selected and due to the low operation frequency and the whole structure no shadow mesh lines nor frequency dependent mesh cells do exist no Jx component would be defined over that conductor In this case EM3DS would issue an Invalid Mesh Warning highlighting in red the conductor were no Jx is defined The same would happen for the dual case of Jz This circumstance does not necessarily indicate an error sometimes one current component may be reasonably neglected due to the particular sizes of the object For example a narrow line oriented along z will probably have a small x component of its current so the user can fruitfully disable the mesh of x border and suppress Jx The same happens sometimes for vias many em 2 5D simulators model them just as vertical Jy currents as the current flows mainly in the y direction at least if rather thin conductors are connected to the via The Jy current is sufficient to connect two conductors in two layers This is the case shown in figure 24 C L R R Ts R L Pff ZT V7 Wl la a 30 View io E4 Co Te Fig 24 By
5. In both MESFET and HEMT families the gate electrodes form a Schottky junction with the underlying layer but their behavior in the normal operating mode is rather different In the pHEMT of figure above the doped AlGaAs region may be assumed to be completely depleted as usually the case for normal HEMT operation in order to avoid parasitic paths between source and drain the incoming electric field over the complete AlGaAs layer controls the density of the 2DEG In the MESFET on the other hand the depletion region controls the width of the channel modulating the total current flowing from source to drain Due to the small signal hypothesis it is assumed the depletion cross sectional dimensions to be fixed while the channel current density to be modulated by the field across the depletion region An important consideration has to be made as to the shape of the depletion region its form is important as it strongly affects the static gate capacitance On the other hand in as far as dynamic effects are concerned the cross sectional dimensions are much smaller than the wavelength up to very high frequencies far beyond the millimeter range For this reason the depletion region is modeled as an insulating layer horizontally limited by the source and drain caps and having a mean depth in order to accounting for the static gate capacitance A more accurate model of the shape of the depletion region is possible indeed by accepting a severe additional c
6. Manual Release October 2011 I What is EM3DS EM3DS is an integral equation based full wave simulator using an approach called Generalized Transverse Resonance Diffraction GTRD Details about the general technique are available in a number of source including the book Advanced Electromagnetic Analysis of Passive and Active Planar Structures by T Rozzi and M Farina IEE Press 1999 and in the paper A 3 D Integral Equation Based Approach to the Analysis of Real Life MMICs Application to Microelectromechanical Systems by M Farina and T Rozzi EEE MTT December 2001 This simulator accounts for finite thickness finite conductivity real conductors dielectrics by using volume currents The structure is still layered but current appears to be arbitrarily oriented J J and J are always present in the 3D mode as consequence the total current may have arbitrary orientation even over sides of a thick conductor This allows EM3DS to fully model also dielectric discontinuities including Dielectric resonators which are out of the scope of traditional 2 5D solvers Moreover the ability to handle conductor thickness which is usually not very important in standard PCB design where substrate losses are dominant and the structures are very large with respect to the metallization thickness it may fundamentally affect results in MMIC design where strips may be a few microns thick and wide Metal thickness is also important in waveguide
7. The frequency dependent mesh cells are in this case also settled by the EM3DS by considering the possibility of slanting lines hence by considering the relative position of vertices However as we have seen this is the weak point of the currently implemented mesh algorithm and curved or slanting lines should be checked by the user more work is being devoted to this problem Playing with the Mesh Options would fix several troubles as it has to be ensured that mesh cells fill the whole shape edge assumes the more general meaning of line between vertices in general polygons so that the rectangular shapes are just a particular case of polygon XI Circles By clicking over Action Add Circular Cond circles approximated by a polygon are added EM3DS displays the window reported below Circular tem ES 629 Fig 33 The Add circle window If Set Center is selected you have to enter in the Center Coord panel the center coordinates Otherwise you are enabled to place the circle by mouse Set Center should be selected if you want to create a parametric circle otherwise parameters are converted to their assigned values Actually what is inserted is a polygon that as discussed in the previous section is modeled by staircase approximation Circle Divisions let you specify how many vertices are used in order to approximate the circle While of course more vertices enable to a better approximation of the circle the mesh den
8. var m tButton f TForm begin f TForm create nil f caption This is my form m tbutton create f m caption test m parent f f show m show m onclick Myonclick end Variable Application Tapplication It is the main EM3DS process Variable nodialogs Boolean If true EM3DS does not issues message dialogs during calculations but only events recorded in the even window Useful for batch simulations Its default value is false and should be always reset to false after calculation Function deembAvailable Boolean Returns true if also calibrated results are available false otherwise Procedure OpenFile const FileName string Open a file with name FileName NOTE this command should only be used from a GLOBAL SCRIPT as when opening a new project project related scripts are de allocated Execution from a local script of this command will cause an Access Violation Error Procedure BrowseFile Opens the Browse file dialog in EM3DS Procedure SaveFile Save the current project Procedure SaveAsBrowse Browse to select a name for a file to be saved Procedure Analyze Analyze the current project Procedure Optimize Run the optimizer Function GetCurrentY RawMatrix indexOfFreq integer var success boolean TSComplexMatrix 98 Provides the uncalibrated Admittance matrix for the calculated structure at the frequency in position indexOfFreg in the frequency list Use function Frequenc
9. Add Script 4dd Script From File 4d Global Script Export EM Results to Touchstone File 4dd a Multimedia Player p y Circuits Delete 3D View 3D view Rendering 1 a Help JE Tools Special Maternals Misc I Symmetry Wizard Several extractors may be allocated by the user in order to allocate a Spice model Extractor you can either select Tools Add Spice Model Extractor or select Add Spice Model Extractor from the Data Browser every Model extractor may be hence accessed by clicking over its symbol in the Data Browser in the Circuits Set 4 i 3D Graphs Spice Model 1 ERK Spice Netlist generated by Spice Model Extractor 2 0 by MEM Research 2005 SUBCKT DR_Ny 3 1 2 L113 1 6399456E 11 R130 0 96160426 L21 4 2 1102775E 1 R2 40 1 184607 L315657123E 11 R350 16585894 L416 4535 965E 1 1 R46 O 6384 7 561 Rb 70 1671 2602 C1 706 51305686E 13 Fig 94 Spice Model Extractor 89 The model is described as a set of nodes and a set of lumped elements between the nodes that can reproduce the electrical behaviour of electromagnetic structure The new spice model extractor allows extracting a lumped model for arbitrary structures The model is described as a set of nodes and a set of lumped elements between the nodes that can reproduce the electrical behavior of electromagnetic structure In order to extract the model all frequencies are used the order of the circuit 1s related to the number of frequency points s
10. Press button Create Circuit response with new ports and a new touchstone file is automatically created and link made available in the Ext Data Folder and in any chart as data source XXVII Variables In the Variable parameters panel accessible either from the toolbar from the menu View and from the Data Browser you enter global quantities that can be used anywhere in the EM3DS Geometry can be parametric so that coordinates can be expressions involving parameters modification of the parameters will automatically modify the geometry click on Load Update Variables to make changes effective If a quantity cannot be parametric the parametric value or the expression is resolved immediately replacing the parameter with its value The optimizer uses the defined variables to perform its task If a coordinate is entered as parameter but the user moves the item either by the mouse or the keyboard arrows parameter is replaced with its numerical value and that coordinate is no longer parametric XXVIII Macromodel builder Ay This form is accessible either by the main menu gt Tools gt Macromodel builder or the button Ln the same icon in the Data Browser i MacroModel Builder Ver 1 0 Bounds wi Varable Bo o ates 3 Humber of simulations 150 Upper Interpolated points in Macromodel 250 Refresh List of Varnables Create Macro Model Help M Apply Correction relative comection thereshold 1e 3 W Linear Interpolatio
11. Re le T fi Of course if frequencies are equispaced include the DC term and the minimum frequency is equal to the interval between the different frequency points we are basically doing a Fourier transform The key is that the EM3DS choice let you explore more possibilities taking under control what is going on In the case of a Fourier Transform you are seeing in time the response to a pulse with finite bandwidth basically a convolution between a pulse and a sinx x function The larger the upper frequency the narrower is the pulse The lower frequency define the range namely the maximum time after which you get a replica of your pulse 1 fmin In order to reduce the ripple it is possible to weight the spectral content by some windowing function making smoother the transition in frequency at the edge of the band EM3DS implements internally the Kaiser Beta function so that when Kaiser Beta is enabled the response is s f Fe S LEA lal pire f The ripple is reduced but the stimulus results larger in time The more the Beta factor the smoother is the response Actually EM3DS let you define also your own weighting function u f so that you can evaluate the response e f Re Sle Alef el f to the stimulus sH Re Y lulh jet T f You can always see the stimulus and the response which are evaluated in real time When looking the TDR response in a chart remind that by default S parameters are normalized at 50 Ohms your
12. The first step is hence to set the size of this waveguide To this aim either click over Settings Box Dimensions menu or over the Box Size button in the toolbar The window shown below appears Here you also select the units used to draw the structure Box Dimensions Units mm M Metric Apply Cancel Fig 6 Box dimensions FAQ 1 How do I select the size of the enclosure There are a few rules to be respected when setting up the size of the enclosure Certainly the box must be larger than the structure itself However a major factor affecting the computational time and load 1 e required memory is the ratio between the size of enclosure and the size of the smaller part of the structure Large circuits should be broken down to smaller circuits and the results combined at a network level As a rule of thumb to minimize the interaction between the circuit analyzed and the waveguide walls lateral walls should be placed at a distance twice the substrate thickness It is approximately the same rule that may be applied to evaluate the distance at which two parts of a circuit may be considered standalone If you analyze devices supposed to radiate in an open environment like antennas you should follow the guidelines laid off in detail in the paragraph Antenna modeling Select the composition of the substrate the substrate is a multilayered possibly lossy dielectric stack By clicking over the Analysis and Substrate Settings button
13. f shor end procedure myMenuezcClick sender tohjyect begin Analyze end begin mi tmenuitem create mainENsDSmenu gt mi caption My Menu wi onclick GmyMenucLick mi wisihble true maLlnENsDSmenu items add mil fi tform create nil m TmainMenu create tft miz tmenuitem create im miz onc lick SmyMenue CLick miz Visible true tig caption analyze m items addi mizi Fig 98 Script Compiler ig Iv Scripting will always be in the source format and stored separately in a file linked to the project local or to EM3DS itself global It is compiled and then run For debugging purposes one can add break points by the popup menu right click or execute step by step see menu or compile etc A complete menu and new toolbar is made available So far there are some restrictions uses clause is not yet implemented pointers are not allowed and is not possible to create new classes But a number of classes are already implemented They include see Borland Dephi or the online help for reference about their use Classes TSPEEDBUTTON TCUSTOMGROUPBOX TGROUPBOX TCUSTOMLABEL TLABEL TCUSTOMEDIT TEDIT TCUSTOMMEMO TMEMO TCUSTOMCOMBOBOX TCOMBOBOX TBUTTONCONTROL 94 TBUTTON TCUSTOMCHECKBOX TCHECKBOX TRADIOBUTTON TCUSTOMLISTBOX TLISTBOX TSCROLLBAR TRADIOGROUP TSHAPE TIMAGE TPAINTBOX TBEVEL TTIMER TCUSTOMPANEL TPANEL TFORM TAPPLICATION TPOPUPME
14. or it will be neglected When switching from 3D to 2 5D mode all 3D views are updated in order to make apparent this set of conventions this makes possible to identify problems Also when defining layers a red note will remind if the layer being defined has an actual dimension in space or it is just a dummy layer used to define planar conductors When switching from a 2 5D mode to a 3D mode it may be necessary to remove empty dummy layers and for thick metals contacting in different layers so producing vertical discontinuities to introduce a slicing Ny gt 1 possibly non uniform see below Ver 6 3 may automatically do the job but it will do it in the safer yet possibly time expensive way EM3DS after requesting confirmation will set Ny 3 non uniform in odd layers in any case where even layers via layers contained some objects If EM3DS is used as server for AWR Microwave Office that embeds a 2 5D editor layers are automatically added in order to preserve the correct meaning in the 2 5D mode so that the user has not to be concerned with the translation Fig 7 displays a simpler case of a 2 layer structure default you have layer 2 as labeled and layer 1 for drawing For example in a microstrip circuit layer 1 could be the path layer while layer 2 the substrate where via conductors could be placed Layer Parameters Dielectric permittivity 12a 2 Bulk conductivity 5m OO Cancel tand OO Help Magnetic permeability PO
15. or over the menu Settings Analysis and Subst Settings the Substrate Information window is displayed here you define the cross section of your structure namely number and composition of the dielectric layers filling the waveguide where object are drawn Items e g conductors defined within a layer have the same thickness of the embedding hosting layer Substrate information and e penera options Layer 0 air no object can be plac Layer 1 air path layer AN Layer 2 Gass via layer ayer T ar path layer pave 2 Gas via layer fe ie Add new layer bottom a Delete Layer Pa Perfect Electric PEC Conductivity Insert new layer tand Perfect Magnetic PMC Mag perm E Surometry plane Top stack wal gt Bottom stack wal Lower z b wal i Perfect Electric Conductor top PEC i Perfect Electric Conductor bottom PEC f Perfect Electric PEC Approx Open top Approx Open bottom Perfect Magnetic PMC Material Infinite Waveguide Material Infinite Waveguide C Symmety Plane Perfect Magnetic Conductor top PME Perfect Magnetic Conductor bottom PMC ig Substrate Information window Enclosure Dielectrics Therefore by assigning the thickness of a layer one automatically assigns the thickness of each conductor defined in that layer Figure 7 shows a simple case of a 2 layer structure default you have layer 2 as labeled and la
16. parameters Results may have no meaning Event Error while computing network parameters X lt message gt There is some case where EM3DS is not able to compute the network parameters mainly due to numerical properties of the calculated Y matrix Event Error while computing Network parameters for de embed structure X GHz lt Message gt Error in calculation of the network parameters for the calibration standards Calibrated results may not be available or miss some points but raw results are calculated Message Dialog The MoM Matrix may be incomplete do you want to proceed in computing Network parameters with the available matrix You have aborted calculation when EM3DS was filling the system matrix namely not all modes according to the number of selected modes were used to fill the matrix If you believe that the number of used modes was enough e g because computation was going to terminate network parameters may be calculated from the available incomplete matrix Event Error while loading de embedding files lt message gt Files DL DR etc are where error networks are saved These files are needed in order to re calculate calibrated results If there is some error in loading these files de embedded results may be not available Note that if these files cover just a sub range of the available raw results calibrated results will be available in that sub range in spite of this error message As a general rule de e
17. the de embedding plane distance should not exceed A 4 if this is the case the displayed parameters are unreliable Some minor tests are performed in order to provide a warning message but the user should check after the simulation Note that even if this condition is not respected the de embedding algorithm does not fail as de embed does not assume any pre defined topology only the line parameters will probably be useless Additionally the user can edit the trace properties and the plot area option In this graphs only one trace is currently allowed Feeding Line parameters Mela f Angle Deg Sek Axis Limits Edit T F ti i IK race Properties Line Parameter Plot Options Zo r Crrl C Copy view to clipboard as Bitmap Copy view to clipboard as Metafile At Port Save view to File Left Po Export to File as text Help xi 10 69507 GHz y 56 309036 Fig 86 Feeding line parameters When more than one port is define at the same side characteristic impedance for any of the quasi TEM modes is calculated and can be displayed by selecting Data for Mode However in these conditions the propagation constant and the effective permittivity are only an average value over the different modes To Probe Further The Touchstone Data File Format EM3DS imports and exports data file in Touchstone format Touchstone files are ascii files having a particular extension for example s2p means a 2 port network parameters
18. Available Simulators C AWR EMSight Simulator In Process Ji MEM Research EMS05 Description Electromagnetic 3D Solver Fig 116 AWR Microwave Office 6 adding an EM3DS structure LI The form Preferences This form is accessible either by the main menu gt Settings gt Preferences Aim This is to set up some general preferences in EM3DS The preferences are stored in a file Shapeed9 prf which can be removed and is automatically re created Sle x a Preferences Editor Computation Mesh Humber of Undo Levels Auto Resize Rect for overlap 1 0 Create a 30 view with rendering for new projects iw issue a Warning before unning a script Change Background Color Editor Preferences Auto resize rect for overlap Up to ver 4 2 when drawing conductors having some common parts the program deformed the design so as to guarantee the needed continuity conditions If 2 conductors were in contact one of them was resized in order to overlap the second one the amount of overlapping was selected according to the border ratio of the larger conductor When working with polygons such an overlapping was not automatically performed and the user had to do the work In the current version this is no more necessary Consider that in EM3DS positions are not constrained over any grid so that establishing if two items are or not in contact is a primary issue By right clicking over an item the command
19. Complesso double Modulus of Cl Procedure CSUM a b complesso var c complesso Complex sum c a b Procedure CSUB a b complesso var c complesso Complex subtraction c a b Procedure CMULT a b complesso var C complesso c a b Procedure CRMULT a complesso b extended var C complesso same but b is a real Procedure CIMULT a complesso b extended var C complesso same but b is purely imaginary Procedure CDIV a b complesso var c complesso c a b Procedure CRDIV a complesso b extended var C complesso same but b real Procedure CSIN a complesso var c complesso c sin a Procedure CCOS a complesso var c complesso c cos a Procedure CEXP a complesso var c complesso c exp a Procedure CTAN x complesso var tangent complesso tangent tan x Procedure CTANH x complesso var tangent complesso tangent tanh x Procedure CATANH x complesso var Atangent complesso atangent arc tanh x Procedure CSINH x complesso var C complesso c sinh x Procedure CCOSH x complesso var C complesso c cosh x Procedure INVrp x complesso var modulo fase double modulo magnitude x fase phase x Procedure INVpr modulo fase double var x complesso for a given mag and phase give x Procedure CSQRT x complesso var y complesso y complex square root x Procedure CLN x complesso var y complesso y
20. Copy CTRL C Cut CTRL l 3D View Rendering 1 Paste Ctri Delete Object DEL FG Circuits Mesh Structure Now Ctrl E k Merge Shapes Ext Data Files Translate Copy Move All Objects in layer Ctrl T Help Layer1 Layer 2 x 3750 um z 3125 um Dimensions 1250 1250 Fig 20 Selecting the Mesh Options from the popup menu A denser mesh will provide a greater accuracy only if sharp spatial gradients of the currents actually do exists If this is not the case most probably denser mesh will only mean a waste of resources time and memory Tips press CTRL E or select Mesh Now from the popup menu to see Mesh From the Action menu you can also enable Auto Mesh in this case any click in the editor with enable refresh of mesh When placing a shape depending on the kind of shape being placed e g spiral slanting line etc a set of mesh options is selected as default The set of default mesh options may be user defined by the menu Settings Preferences Mesh There are several general considerations for requiring a user judgement In several cases the structure may display an over mesh as the automatic mesh is selected adopting a worst case approach In some other cases the wavelength may be much shorter than it could be argued by looking at the dielectric stack this is the case of slow wave structures like Metal Insulating Semiconductor MIS structures or more generally whenever losses are involved
21. EM3DS is able to handle this way the following files EMS EM3DS project the action is opening the project GDSII GDSII file the action is importing file in EM3DS S P Z P Y P Touchstone files EM3DS imports them as External Data Files NET circuit EM3DS creates a circuit window and imports the file XLVII Antenna modeling As highlighted at the beginning of this manual the structures analyzed are enclosed in a waveguide that may be either infinite in the vertical y direction possibly filled by any lossy or lossless material hint using lossy material allows rigorous modeling of lossy ground planes in microstrip backed CPW etc closed with perfect conductors so as to form a closed box or terminated over absorbing boundaries approx 377 Ohm the characteristic impedance of plane waves see p 6 This particular assumption poses some limitation on the class of antennas that can be modeled Nonetheless antennas may be simulated by using some care A large box may be used to model the open space The matter is what we mean by the term large 102 Leaking power Enclosing Wavguide Bottom Wall Ground Fig 105 Modeling radiation Let us refer to a radiating patch schematically shown in fig 05 In order to model radiating energy we need power leaking in the vertical direction this way if we draw a 2 port some energy is lost in spite of having selected a lossless structure Such a leakage is
22. For broadband analysis a better choice would be to obtain asymptotic data in the middle frequency This is possible by running a simulation from middle to upper frequency and then by changing the frequency band for the remaining part however you have to select NO when EM3DS asks you if updating mesh as consequence of having changed the upper frequency of analysis or the asymptotic part is discarded This way the time required for a full 3D simulation is dramatically reduced while preserving the accuracy Settings about the asymptotic estimator enabled by default are available within the Project Data window namely by clicking over the Settings Analysis and Substrate settings menu If the check box Asymptotic Approximation is selected EM3DS computes and stores information about the frequency behavior of the Green Function and uses this information to dramatically speed up the simulation over the remaining frequency range where only the modes indicated in the Involved modes panel are used The lower the Involved modes the lower the simulation time More modes mean more accuracy however generally no more than 10 modes both in x and z direction are needed to obtain excellent results In some cases 3 5 modes may be enough If the number of involved modes is lower than the minimum suggested a warning message is added into the event window Results may lose precision in the higher frequency range Some care is only needed if a conductor is placed
23. Functions now available in the toolbar port numbering highlight of the active layer in the 3D view and much more Version 8 2006 already included several breakthrough features some of them summarized here e Magnetic walls top and bottom cover may be magnetic wall namely tangential H vanishing by the same token two of the 4 side walls may be magnetic e Symmetry wizard magnetic walls may be used to simulate half a symmetric structure so saving large amount of time When there are ports by replacing in a two step procedure the symmetry plane by means of a magnetic and then an electric wall the response of the whole device may be obtained by suitably superimposing the two half structures each one featuring one half of the total number of ports The symmetry wizard is a simple post processor generating the correct superposition of the two simulations recreating the full port solution e Batch planner it allows creating a queue of simulations optimizations to be automatically ran and saved e Differential ports a new post processor allows to renumber ports connect ports together and creation of response to even excitations evaluate the differential balanced or odd response of the circuit etc e Enhanced editor now you can select multiple objects and change their properties all at once resistivity mesh move by arrows etc Each layer can be labeled e g Gallium Arsenide copper etc so that it becomes easier to identify t
24. If the specific property does not support parameters e g the box size in the plane direction in the present version the parameter is immediately resolved for and only its current numeric value is used Note also that parameters will be the mean to modify your structure via your own script see the Script section for more information Coming back to our structure the rectangle is placed in layer 1 and has thickness of layer 1 as you were in layer 1 when entering the shape We have not yet specified the material composing such a shape To this aim select from the popup menu available when right clicking over the rectangle resistivity Material Specifications or simply Resistivity from the same dialog where you have entered the coordinates Set the resistivity to 2 5e 8 Ohm m remember this is resistivity not conductivity in contrast to the specifications of the embedding dielectrics However we have deliberately left layer 1 and any of its object to have a very reduced thickness fraction of microns Hence any conductors having non 40 zero resistivity would have a very high total resistance In order to avoid this problem the resistivity has to be scaled to the actual wanted conductor thickness namely 2 microns hence select scale resistivity and enter into the scale to thickness 2 microns We can also select Force skin effect as we are considering very thin conductors in this layer no skin effect would appe
25. In this case it is likely your structure require a mesh denser than automatically settled Due to the lack of a grid mesh lines may be generated that would require a large number of modes General polygons or slanting lines are where user insight is absolutely needed see next paragraph FAQ 3 I have drawn a very simple structure and in spite of this it seems to require a large computational time Where I m getting wrong The most common error producing a large computational time is a wrong setting of the mesh options see the previous paragraph In the present version much work has been devoted so as to reduce this source of error However the user should be careful as well Mesh lines may be settled by selecting click by mouse a shape right clicking so as to display the popup menu and by selecting the Mesh Options The time needed for a simulation rises very fast with the number of box modes displayed by clicking over Settings Analysis and Subs Settings from the main menu The suggested value for the number of modes is directly related to ratio between the enclosure dimensions and the minimum distance between two mesh lines in the same conductor 24 EM3DS Electromagnetic 3D Solver File Edit view Settings Action Tools Window Help 7 Editor OK 3D View Rendering O x Frequency dependent Mesh lines Le Data Browser BAA gt HE Tools Special Materials Misc g Ext Da
26. Information Window Here you can also Enter as start frequency 2 GHz stop frequency 40 GHz and num Points 20 at the upper right corner a small message informs you that the selected frequency step is 2 GHz there are other parameters to be selected in this window but you ll need to change those parameters after editing the structure If you want you can also select Invoke automatically SmartFIT in this case EM3DS will use SmartFIT namely an adaptive calculation of the frequency points the final number of points is the one selected in SmartFIT so that in such a case the Num Points info is not used In the same window select the panel Enclosure Dielectrics 37 lt EM3DS Electromagnetic 3D Solver Bag el Editor a DD 3D View Comp options Enclosure dielectrics Dielectrics Layer 0 air no object can be plac K Layer 1 air path layer Layer Parameters Dielectric permittivity 112 9 Bulk conductivity Sm fo tand fo Layer 2 GaAs via layer Magnetic permeability f Add z Data about Layer 2 Gads via lay Layer thickness mm fi new __ Add new layer bottom ottom thickness 1 000E 0 mm Layer name comment Gas SS aie Delete Layer Porm Te 0 000E 0 Sm sigma Insert new layer tand 0 000E 0 mag perm 1 Top stack wall Bottom stack wall k Perfect Electric Conductor top PEC Perfect Electric Standard 3D View Approx Open top C Approx Open be Material Infinite Wavegui
27. Layer display currents for the selected layer Current Component Displayed Currents select if displaying Jx Jy Jz or the total current 82 density Termination Ports it is activated for 2 or more ports if Short is selected short circuit currents are displayed otherwise currents are calculated for the selected port impedance In order to change this impedance just double click over the port Values Graph Options shows the max and min values for the displayed plot these values are automatically updated unless the Set fixed Range box is selected Keep Aspect Ratio Graph Options if selected the x z dimensions are displayed respecting their real ratio default Right click over the plot to handle it namely to rotate it move it or zoom Operations are performed by dragging mouse over the graph You can hide the lower control panel by deselecting from the popup menu Display Setup panel Operations are performed by dragging the mouse over the image The current view may be exported to file as Windows BMP or EMF Enhanced Metafile vectorial By the same token view may be copied into clipboard In the Animation Window also accessible by menu View you can select start and stop frames and save animation as AVI or GIF files The size of the surface plot is changed by changing the window size The animation produced has the same size of the surface plot From the Data Browser or from the menu View you can add several standar
28. Start Frequency GH Material Name Zn0_FBAR45 mas Stop Frequency GHz 61 Num steps Step 0 01 GHz Create Reference to Material Analyze Fig 111 Form used to define acoustic properties of a BAW You can add several forms of this kind and access them by double clicking over icons in the Data Browser in the folder Tools Special Materials Misc In this form you specify the acoustic properties of the material composing the bulk acoustic wave resonator There are a few assumptions beneath the performed analysis the analysis only accounts for pure mode either longitudinal or shear and the propagation properties have to refer to the considered modes Mode coupling due to imperfect crystal orientation is not accounted for only one piezoelectric film may be specified for a resonator the piezoelectric film is the only one having non zero bulk electromechanical coupling k The number of the additional materials is on the other hand completely arbitrary and the mechanical loading effect is rigorously accounted for While generally piezoelectric materials are generally anisotropic so far material is handled as isotropic and considering permittivity on the direction orthogonal to the piezoelectric film this is generally acceptable in pure mode thin film structures FBAR You can add a material always added on the bottom of the list or delete any selected material Not all parameters are independent e g by modifying the densi
29. a reference to where arguments highlighting how to solve the problem if any may be found Message Dialog indicates a dialog box where the message is displayed while Event indicates that the message only appears in the Events Messages window silent messages Fatal messages are the only one interrupting calculation while any other message does not necessarily indicate errors in results Message Dialog The highlighted conductor seems to contain too many mesh cells mesh procedure may take a while However it is possible that this high number is a consequence of an error when drawing the structure Such a condition occurs if you have a very large structure with respect to the wavelength e g you may have selected wrong units either when specifying the box size or when setting the upper frequency of analysis or simply you have manually selected very small mesh cells in the Mesh Options This is a rather self explaining message before performing automatic mesh EM3DS checks if the number of cells is suspect In this case the above message is issued By clicking over Abort button mesh is not performed and the user can check if there is actually an error In order to avoid repeated display of this message disable temporarily the automatic mesh menu Action Mesh Event Warning the reference plane at the XX Hand Side should be placed after at least one mesh cell Hint Try by raising the Border Mesh ratio XX and by checking Draw Border Ratio XX Yo
30. accessed directly from the AWR Microwave Office since version 6 of MWO suite This means that AWR s customers are able to see EM3DS as an electromagnetic engine still using Microwave Office editor and post processing capabilities Refers to the section for details on how to use this feature IT What s new in Ver 12 2011 e Extended parametric features substrates can have parametric thickness e Parametric analysis define several sets of parameters and perform group of simulations Now printing of any chart graphic text is implemented Additional tutorials FreeEM3DS much more powerful Bug fixing Since version 11 2010 EM3DS featured e Time Domain Reflectometry TDR transient analysis in time domain of the signals e Time Domain animation of currents and fields analysis of current and field distributions in time e Custom Measurements ability to define and add your own new measurements Moreover in the editor automatic align of rectangular shapes Since version 10 2008 EM3DS featured Macromodeling creating macromodels which allow to see how the response of circuit is modified in real time for a modification of a parameter Macromodel optimization the optimization can either run on a macro model or a native electromagnetic structure Macromodel tuning move the tuner slider and see how the response changes Updated help migrated into HTML format and reviewed Animated online tutorials reduces the time needed to exploi
31. as tunable in the optimizer panel Variables can also be accessed through a pascal script namely by writing a pascal code directly in EM3DS As to the speed EM3DS always performed very well thanks to its Asymptotic Estimator which performs a full simulation only at the first frequency point Moreover since version 7 is available a new powerful device SmartFIT this algorithm adaptively drives the EM solver generating a frequency list within the user selected band At the end it estimate the response all over that band in tents or hundreds of points Of course it is possible to exploit a rational interpolator even in post processing but without the same guarantee to get good results An important companion to this algorithm is a wide band Spice Model extractor it generates a network which reproduces the response all over the band regardless of the electrical length of the EM circuit In the release 9 several completely new features were added such as internal planar ports antenna functions namely sense layer to see the E field and to evaluate radiated far field both in standard polar diagrams or in 3D surfaces object oriented pascal scripting tuner enhanced editing etc In version 10 you will find a first version of a Macromodel creator for a given parameter EM3DS extracts some features in order to be able to predict the circuit response in real time when such a parameter is modified This is an extremely useful tool for the desi
32. assign values e g equal to the ones of the passivation layer so that whenever we revert to the 3D mode we have not necessarily delete it of course in that case we should add lateral CPW conductors to maintain the current continuity when layer has finite thickness Now edge ports are in layer 5 which is odd then a standard conductor layer Hence ok Layer 6 the oxide substrate is an even layer hence hosting vias and substrate even in this case no modification is necessary The problem is with layer 7 that was supposed to be the silicon substrate but substrate must be in an even layer So before layer 7 we will add one more dummy layer Even in this case we can use the physical properties of layer 7 while not strictly necessary We usually recommend doing that in order to avoid confusion Now the 2 5D project is ready you should have 8 layers and you can run the whole simulation in a time which is a fraction of the one needed by the 3D simulation EM3DS Electromagnetic 3D Solver Window oe v lt EM3DS loaded D DATA AWR COM EM_Socket MEMResearch Source EM3DS 7 MEMSTutorial25Dmore EMS O X lt 3D View Rendering 1 f OR General Draw Edit tools Post Processing Sela gt 4 F measured Plot Mode rotate e F ps lt Data Browser BAA s a 2D Graphs Dei Graph 1 3D Graphs Current Density 1 T Editor 3D Views lt e Standard 3D View To Port i Net Parameters s Synch
33. available in the data browser and in any chart containing the estimated response The new data set is always saved into the HD with a unique name possibly containing a progressive number You can access it either from the toolbar or from the menu Tools SmartFIT Menu Action SmartFIT Computation directly run a simulation driven by SmartFIT SmartFIT will ever start at equally spaced frequencies defined by the Number of Starting Points usually 3 band extremes and one middle point Then it will iteratively progress until the result is within the Maximum relative error or the maximum number of iterations has been exceeded Note that if the number of evaluated frequency points is too large the estimation may be poor and no convergence is obtained while quite rare in that case consider to subsection your frequency band In any case the spot frequency response is available The prediction is performed over a number of frequency points according to what entered in Interpolated Points in SmartFitting You can also leave this number low to speed up the process and then tentatively create a new interpolated data set in post processing from the popup menu in any chart the interpolated data set will have as many points as specified in Number Of Interpolated Points In this case one should use as input Data Source the current EM simulation not the interpolated one as the number of input points should not exceed 40 50 Also not
34. by clicking the first time over the workspace while after a second click the right bottom corner is settled and the conductor is drawn The horizontal co ordinate is referred to x direction while the vertical one is z direction the design is a top view but a real time 3D view is always available where the active layer is highlighted in red The direction normal to the dielectric plane is the y direction namely the direction of the conductor thickness and of the dielectric stack substrate The axis origin is the top left corner on the screen The reference system is displayed whenever attempting to modify conductor or box dimensions When clicking over Add Polygonal cond Menu a dialog box will ask you if the polygon has to drawn by mouse or by specifying vertices In the first case every click will identify a vertex while pressing ESC or by right clicking and selecting Close Polygon from the popup menu or by clicking a second time on the Polygon button the first and the last vertices will be joined forming a complete polygon If you draw a polygon that is actually a rectangle shape is automatically converted into a rectangle namely sharing all the features of rectangular shapes as the possibility of adding ports Polygons can accept ports the only limitation is that to a single object shape no more than one port per side can be added if more ports are necessary just split the object in two or more shapes Also it is possible to add
35. can verify to some extent the validity of your calibration by e g analyzing an empty waveguide having some length more than the one used in creating standard Calibration should provide you perfect match namely S11 less 60 dB often even less 100dB The phase of S21 may be compared to what analytically expected Note that also multiport waveguide component can be analyzed in principle you should only create the above calibration files for each ports and then connect them to the multiport structure by means of the embedded circuit simulator XXIV Multimode Waveguide calibration The problem can be formulated as follows let us consider the problem of getting a the Generalized Admittance Matrix GAM of a circuit involving N ports attached to a planar circuit and N modes either below or above cut off basically you want to characterize a circuit involving both standard gap ports external ports attached to strips and some kind of internal modal ports exploiting only measurement made on the external ports There are two possible procedures You will need to build two or three standards namely additional simulations according to the selected calibration procedure 60 2d Multi mode Waveguide calibration GAM output Generalized Admittance Matrix Mia EW Files Help Thru Standard Waveguide permittivity Standard at 37 Ohm Load from file load for standard 1 Dielectric 1 Reactive Load Above is short _ Load from file
36. connect 2 thin conductors the first and the last thin slices by via the middle slice upper and lower conductors experience most of the horizontal current flow while the middle one supports a great vertical y component In ideal conductors this is generally ok as we know that currents have to flow across the surfaces but in lossy conductors this lead to a wrong resistance of a conductor EM3DS implements an internal correction for this case Ny non uniform and lossy conductors but one should be aware this is only an approximation This is why when using lossy conductors with non uniform slicing a reminder in the Message window is displayed By the way this expedient works remarkably well Coming back to the standard uniform Ny generally speaking Ny in lossy conductors has to be chosen in order to allow to correctly model the skin effect with increasing frequency hence Ny is the parameter controlling the accuracy in the evaluation of losses for high frequencies one slice should be thinner than the skin depth at the upper frequency Still it is possible to keep Ny 1 and when defining the conductor resistivity to select the check box Force Skin Effect In this case the resistivity is assumed to have frequency dependence accounting for skin effect Note that the frequency variation is evaluated by assuming that the currents penetrate only the lower faces of a strip This assumption is generally good for microstrips but may be poor for other
37. define here Then click on Add a new set button at this point in the upper list it will appear a new item showing the name of the set and its content To delete a defined set or a group of them just click and press Delete set button When you click on Run Parametric Simulation a number of simulations will be performed setting automatically the variables as required by your defined set Resulting port parameters will be saved and re imported in the project so that you will have them available for plotting in any chart and to make comparisons among different set of parameters The kind of port to be saved is selected in the bottom of the form choose which port parameters S Y Z and if either to work on De Embedded or raw data You can also request to create a separate complete project for each set of variables by selecting Save each simulation as a complete project As a result everything will be saved currents raw and calibrated data etc for each set of data XXXII Post Processing displaying network parameters and using the Data Browser EM3DS includes complete and powerful post processing abilities Network plots are accessed either by clicking over View Graph menu or the network parameters button or by the Data browser window Data Browser has been added in ver 5 0 in order to simplify post processing The Data Browser is basically a tree that can be expanded by clicking over the single leaves Some parts of the tree suc
38. described in this section The process of defining the rectangular sub domains is usually indicated as meshing while sub domains are mesh cells Mesh cells are automatically defined in EM3DS 1 e the meshing procedure is automatic However it is easy to understand how the meshing procedure is a key process in obtaining an efficient and reliable simulation Users should anyway understand some basic rules underlying the mesh process Meshing is performed automatically over any shape drawn by the user in the workspace It is a real time process so that any time you click in the blank part of the workspace shapes are meshed You can disable or enable the real time mesh by clicking over Action Mesh in complex structures especially involving curves mesh may take time Meshing is performed according to the Mesh Options Mesh options are local properties that is each shape has its mesh options that are automatically settled by EM3DS but that the user can and sometimes should access and modify To this end you have only to select a shape right click over it in order to see the popup menu and to select Mesh Options as displayed in figure below fig 20 Properly selecting Mesh Options requires some more insight about the mesh algorithm Mesh cells being rectangular domains are identified by mesh lines or intervals namely horizontal x and vertical z intervals These intervals are placed according to a few basic rules see figure 27 the
39. ee jonu xF This approach is quite good and works well at least for calculating broadside antennas Results in terms of radiation patterns however have to be interpreted knowing the above assumptions one recovers the E field radiated in presence of the perfect conductor seen above y Perfect conductor Circuit Dielectric Actual radiation conditions Stack Fig 109 One should always keep in mind that the radiation pattern is obtained considering that the radiating structure is radiating in a large cavity embedded in a metal plane The figure above shows a cross section side view of a microstrip circuit and the actual conditions used in calculating radiation patterns It is evident that the absorbing boundary position is critical if too close to the circuit there will be interaction with the near field while if too far the radiation pattern will become the one of an aperture in a standard rectangular waveguide Hence a trade off is usually needed as indicated above for a microstrip antenna and several others A 2 resulted to be a good choice While modeling an end fire antenna e g a Yagi Uda the end fire characteristic will be apparent but a null corresponding to the perfect conductor will always be present 105 EndF ire Aray EMS 160 160 Fig 110 Three elements plus one reflector and one director phase difference between elements 90 planar Yagi Uda E with 0 sweeping End fire behavior is
40. filters consider e g that in single cavity WR90 resonator neglecting the iris thickness may produce a resonant frequency shift of over 5 EM3DS is mainly aimed at the analysis of planar structures but due to its 3D nature it may be used also to address some other problems like the modeling of waveguide filters with arbitrary thick possibly lossy irises Actually EM3DS embodies in fact 2 EM Solvers 2 5D and 3D Which solver to use is rested upon the designer s choice and is a simple click to shift the mode of operation It means that by simple click onto your 3D structure you obtain 2 5D geometry and you can simulate as 2 5D and compare with your 3D simulation The speed is increased in 2 5D mode by a factor varying from 50 up to more than 300 the more the structure is complex the larger is the time saved The 2 5D mode comes as a limit of the 3D formulation keeping several attracting capabilities of the 3D mode EM3DS comes with a complete set of tools The most important is maybe the panel for global parameters variables the panel allows you to define variables and to parameterize the geometrical features of your objects This means that you can modify and optimize your design without painfully entering new dimensions shape by shape The optimization can either be manual the designer does the work or exploit the embedded optimizer Variables can be modified also accessing a tuner a set of sliders varying those variable indicated
41. first and the last slices are lum Xle 3 Inm thick Y subsections Embedding layer hinner subsections Fig 11 Meaning of parameter Non Uniform y subsect Using non uniform subsections is recommended when a finite thickness conductor in a layer is in contact with one conductor in other layer The sharp vertical discontinuity is correctly modelled with a minimum value of Ny 3 providing a powerful additional device to address problems related to such a discontinuity Moreover in ideal conductors the current should be nearly completely distributed over the surface of the conductors the non uniform vertical mesh allows to describe the current more physically with a reduced set of expanding functions 12 However in lossy conductors such a choice may constraint currents to flow in an unnatural manner for low frequencies the current is evenly distributed across the conductor section and adopting the non uniform vertical sub sectioning is equivalent to do a possibly wrong assumption about the current distribution An internal device automatically compensates this related phenomenon so as to provide accurate results as well but the user should keep in mind that the compensation relies on a set of hypothesis Non uniform slicing should not be used if the layer hosts for example a dielectric resonator Uniform y subsectioning allows to get the physical behaviour of current density as a function of the frequency describing the skin effect
42. force B to have its z edge mesh line and A to have its x edge mesh line for example in the middle to this aim be sure that Add Edge Mesh options are checked and raise the value of the edge mesh distance at least up to the ratio between the z box dimension and the width of conductor B dual for A However it is apparent as in this case the number of required modes to build the solution is doubled in both directions as the minimum distance between close mesh lines including the rectangle sides is reduced to one half A more economic solution is simply to completely overlap conductor A to conductor B as this way there is at least one cell having contemporarily both Jx and Jz so as to guarantee the correct boundary condition Figure 26 displays one possible case where optimization of the mesh by the user will save a large amount of time One Shadow mesh line in the middle conductor due to the conductor on the left hand side is very close to the one due to the conductor on the right Most probably displacing vertically one of the two conductors up to merge the shadow mesh lines will not affect the accuracy as in order to be a problem the two positions have to be very close while substantially reducing the number of required modes in the z direction Remind that this number is directly proportional to the ratio between the enclosure dimension along z and the vertical distance between the closer horizontal mesh lines As it is apparent th
43. from the graph in pixels used to define the frame they can be changed in order to keep space for the captions X Format and y Format allow to specify the format number for abscissa and value The value of x y Format is a string that encodes the formatting of numeric data using the specifiers in the following table Specifier Represents 0 Digit placeholder If the value being formatted has a digit in the position where the 0 appears in the format string then that digit is copied to the output string Otherwise a 0 is stored in that position in the output string Digit placeholder If the value being formatted has a digit in the position where the appears in the format string then that digit is copied to the output string Otherwise nothing is stored in that position in the output string Decimal point The first character in the format string determines the location of the decimal separator in the formatted value any additional characters are ignored Thousand separator If the format string contains one or more characters the output will have thousand separators inserted between each group of three digits to the left of the decimal point The placement and number of characters in the format string does not affect the output except to indicate that thousand separators are wanted E Scientific notation If any of the strings E E e or e are contained in the format string the number is formatted using sc
44. ideal transmission line between nodes 1 and 2 1 cm long 50 Ohm and 4 as effective dielectric permittivity You can add references to external data or em simulation as subcircuits The syntax is X lt n1 gt lt n2 gt lt nn gt subckt lt name gt The name is one of the names appearing in Data Browser window in the Ext Data Files folder For example X1 123 subckt circuit y3p Is the circuit circuit y3p connected to nodes 1 2 and 3 You can simply add a subcircuit by menu by selecting add subcircuit and hence by clicking over the desired subcircuit in the Ext Data Files folder of the Data Browser An additional particular kind of subcircuit the Negate multi port is included in order to allow manual calibration procedures Such a component allows to remove the effect of the given subcircuit see figure below The syntax is the same of subcircuits but the are labelled with string beginning with N For example N1 123 subckt circuit y3p 91 NEG S1 S2 Fig 96 Effect of connecting a NEG component If a given circuit may be considered as the interconnection of S1 and S2 and we have an evaluation of S1 by connecting Neg S1 to the circuit we can recover S2 This works for arbitrary multiports Calibration of via ports that are not automatically calibrated may be performed by using this strategy S1 in this case would be the em simulation of the only via port NOTE about using NEG whenever you have n ports
45. indicated in the post processing sections To this aim one has to add a Sense Layer menu Action Add Sense Layer When selecting Add Sense Layer EM3DS 1 sets the top enclosure to Approx Open namely the top cover of the metal box enclosing the circuit is replaced by an absorbing boundary which mimics the 377 Ohms seen by a plane wave in free space This approximation is a good approximation for open space if the lateral metal wall are kept far enough from the structure and the absorbing boundary is at a distance so as not intercepting the radiated near field 2 adds two layers 1 and 2 on top of your structure the first one touches the absorbing boundary ad is labeled as sense layer while the second one is a spacer between the absorbing boundary and the structure Layer O is settled to 0 thickness and labeled as null layer basically is the same as 103 if we were removed that layer 3 Inserts in layer 1 a thin lossy conductor the conductor is so thin and so lossy that it nearly does not affect the calculation of the network parameters basically transparent However owing to Ohm s law induced currents are proportional to electrical fields and this way EM3DS recover the field distribution in the sense layer without the explicit need of the Green s function Such a field is available in any current plot The thin conductor cannot be edited by the user however the user can modify its mesh properties This is im
46. internal ports are not automatically calibrated in the present version so that the port discontinuity is included in the results even though it can be removed manually by using negate sub circuit in the circuit Note that in 2 5D mode planar currents are only defined over odd layers As a consequence planar internal ports may only be defined in odd layers In 3D mode there is no such a restriction Select ports by mouse then access additional properties by the popup menu e g port impedance calibration plane Press DEL to remove the selected port Via ports either ground referenced or internal off ground are impulsive field generators applied at the bottom of a given conductor hence no via is actually added and if needed the user should add a via conductor Results in terms of network parameters are either ground referenced or off ground internal depending on the position of the conductor to which the via port is associated Refer to the section describing the circuit simulator to have more information on how correctly using results obtained with off ground ports If the conductor is in the lower layer and a perfect conductor plane is selected as bottom plane results are ground referenced No automatic de embedding is implemented for via ports in the present version In order to add via port simply click over the via port button and then over the desired conductor In 2 5D working mode via ports can only be added to conduc
47. its lines of force as straight lines in the depletion region and by imposing continuity of the electric flux density across the boundary between the two regions one obtains Fomb TE ripi l a aale aee Hl 2 side T 2E mb f depl The total gate capacitance per unit length is obtained by adding to eqn 1 twice the value of eqn 2 For T shaped gates some further usually minor correction may be needed Its amount is evaluated by calculating the capacitance of the upper part of the T gate alone The needed differential static gate capacitance as function of the bias point may obtained by using the non linear models Note that this way the present model is able to completely predict performances of a device simply starting from structural parameters virtually avoiding any fitting However to this aim a detailed knowledge of the physical parameters is needed these parameters are often not available or at least they are not known to the degree of precision necessary for a reliable simulation On the other hand measurements on a given sample may be available in this case the static gate capacitance is derived by fitting at the bias point measured low frequency S parameters to the lumped equivalent circuit for the device The advantage of the latter approach is that one does not have to distinguish between MESFET and HEMT devices as the equivalent circuits share the same topology and the present method may still be used in order to anal
48. may be useful in order to reduce the complexity of a polygon used to approximate e g a curve To this aim once settled the distance press the Delete Pts button Changes will take effect only after pressing Apply or OK The Round Dim button allows rounding of the vertex positions all at once Displace allows moving the whole object of a given amount In any case changes are only effective when pressing Apply or Ok Polygon Properties Paints Delete Points closer than 1 Vertes number 8750 as ooo ooo Displace 3125 U distance Mesh Op Add Port Delete Current Point Hela area Resistivity Units fv Metric Delete Collinear Paints Caed Heb Round Din Fig 28 Polygon dialog window IHE Note that in any co ordinate you can enter parameters or expressions involving parameters not the frequency This allows you to create a parametric geometry Manhattan polygons are those polygons that you can directly draw by combining rectangles you can use the Add Polygon button for both Manhattan and non Manhattan Polygons However shapes drawn this way are subjected to a few restrictions ports may only be added to rectangular conductors so if you have to add a port you have to add to your structure a rectangular shape Polygons that are actually rectangles are automatically converted in rectangles so that ports may be added In the present version a number or rectangular domains model slanting lines namely b
49. merged e g rings but overlap should not be over the line cutting the ring every polygon with holes has a cutting line has polygons are defined by connecting first and last vertex Fig 39 Example of circular Wilkinson power divider in EM3DS the structure has been obtained by merging curves and slanting lines 34 XVII A simple step by step example a MEMS Switch There are several way to learn about using EM3DS the most effective are the animated tutorials In the following we will describe step by step how to enter a MEMS switch Start EM3DS by clicking over EM3DS 12 exe icon By moving the mouse over the upper button toolbar hints are displayed about the button functions In the following we will assume these hints to be the name of the buttons 1 The first step is selecting the enclosure dimensions Your structure is enclosed in a metallic box the walls being the four sides the upper and the lower planes may be actually open of the windows where you draw the structure work area To this aim select the General panel and the button Box size or by the main menu Settings Box Dimensions Ws D DATA AWR COM EM_Socket MEMResearch Source EM3DS 7 Untitled EMS C X 3D View Rendering General Draw Edit tools Post Processing Box Dimensions Dimensions gt HE a Plot Mode rotate Data Browser Paramete Units Jum l V Metric i Apply Cancel rail
50. mesh cell size one obtains an acceptable mesh Usually slanting lines are better meshed by using the uniform mesh option default for add slanting line By recalling what we have said in the previous section To probe Further a horizontal current is only defined over a rectangle if at least one horizontal division vertical mesh line of the rectangle appears Dual reasoning for vertical currents it is straightforward understanding as this is the simpler mesh accounting for the correct continuity of the currents The schematic path of the current is displayed in fig 32 30 oe ee lt 7 eee oe alee FAs i ll 4 hase A C i CEA EEE I RAA Fig 32 Schematic of the current path To Probe Further How polygons are meshed Meshing rule for polygons are slightly different actually only a super set than those described in the previous section Mesh lines if uniform mesh is not selected are in fact associated to each polygon vertex This explains why sometimes reducing the number of vertices e g convert a circle into a polygon with a reasonable number of vertices may be necessary Also consider that each vertex touching an other shape produces a shadow mesh line see previous section Additionally each vertex belonging to polygons in other layers will also produce shadow mesh However the latter can be avoided 1f in the mesh options the checkbox no shadow mesh cell is selected
51. new computer needs a new license User Code Required Please send the installation code to infotimemrresearch com lt click here a valid user code will be sent as soon as possible a pone Help Floating License host addr 62 11 74 61 Fig l Request for code EM3DS also supports an alternative licensing scheme namely floating licenses This means that you can run a license manager in a computer where EM3DS has been installed and enabled by the user code and use such a license from a second computer connected via network The License Manager is a program that is installed along with EM3DS and that you have to run in the license server S EM3DS 8 License Manager BR Number of available licenses 0 TCPVIP Allowed Client 12 199 208 130 107 mooo Post Processing a SD ee Bel Dave Clients using licenses User Code Required Remove License from this PC Shark server Install License Manager Service Uninstall License Manager Service Cancel Help tae e host addr 127 0 0 1 Fig 2 License Manager Note that License Manager coming with versions 12 will also work with versions 7 to 11 while EM3DS 12 needs License Manager version 12 Moreover licenses generated for version 12 will work also for versions 7 11 but the contrary is not true Hence owners of EM3DS 7 11 will need to update their license The first thing to do is to insert the TCP IP address or its name in the network in t
52. of different structures be automatically built and calculated the standards so as to be able to extract any effect due to port discontinuity and feeding lines Whenever the device under test DUT is placed in an open waveguide or an infinite waveguide along y it may happen that the different structures are enclosed in waveguide having different modes above cut off If this is the case each structure has a different amount of energy leaking toward infinity or free space The calibration algorithm assumes this energy be the same if this condition is violated you may find even reflection coefficients gt 1 in a calibrated passive circuit note that the raw results are ok The remark highlights that there is such a possibility A different position of the de embedding plane produces different calibration structures and this is the reason of the suggestion Of course if the structure is completely boxed no problem of energy leakage may arise Event WARNING no active brick should be defined between the port and its de embedding plane this happens at XX port s the standard being defined for de embedding may lead to wrong results Active regions cannot appear in calibration structures hence you cannot place active regions between a reference plane and a port Message Dialog Cannot start computation in 2 5D mode either a vertical via port is connected to a shape in an odd path layer or a horizontal edge port is is connected to a sha
53. only possible if at least one mode of the waveguide is over cut off over the whole frequency range Multi mode leakage and large box allows simulating several kind of planar antennas more than satisfactory The upper boundary may be either infinite waveguide or approximately open In this last case care has to be used so to ensure that the absorbing wall be placed far enough so to not directly interact with the near field of the antenna The approx Open boundary is helpful in that sometimes it allows to reduce the size of the box relaxing the need of over cutoff modes we know from the previous sections how reducing the size of the box may substantially save a large amount of computation time The absorbing boundary are hence placed according to the trade off between reducing interaction with near field and providing power leakage even with relaxation of constraints about over cut off modes Usually half a wavelength is OK for most structures Fig 106 L band patch antenna fed by coaxial probe Excitation of patch antennas by coaxial feed is usually well modeled by adding a via port as shown in figure If de embed is enabled and edge ports are used with non zero de embedding planes the use should be careful about the problems discussed in section XXII Radiation pattern can also be calculated and visualized either as polar cuts selecting one of the angular coordinates in the spherical set see section about polar plots or as surface plots as
54. representing Scattering matrix Em3ds handles S Z and Y network parameters with an arbitrary number of ports When exporting a simulation form a network graph the current visualization settings are used in order select which parameter to export Hence if z parameters of the de embedded structure are displayed file of z type is exported including calibrated results Comments are inserted in files by an exclamation point Comments persist until the end of the line Before data header has to be specified The header is indicated by a character Hence the accepted 78 headers are HZ KHZ MHZ GHZ THZ S Y Z MA DB RI R x Where the character is used to separate different choices and the brackets indicate an optional entry Coming to the meaning of the entries Beginning of the header HZ KHZ MHZ GHZ THZ Specifies the frequency units of the data file choose one S Y Z Specifies the parameter type of the data file choose one MA DB RI Specifies how the complex data are presented choose one R x X is areal number that specifies the reference impedance optional Example Headers MHZ S MA R 50 GHZ S DB HZ Y RI Notes 1 The reference impedance is only needed when the parameter type is S scattering coefficients 2 MA and DB means the complex data are in polar form mag angle the angle of which is always in units of degrees DB further specifies that the magnitude has been transfo
55. seen but maximum is not at 90 where it should be and where there is a null due to the ground plane The figure above represents a 3 element planar Yagi Uda plane xz E with o 0 plus one reflector and one director phase difference between elements 90 sweeping O End fire behavior is seen but maximum is not at 90 where it should be and where there is a null due to the ground plane Radiated field is plotted in spherical coordinates Note that actually the above system maintained for backward compatibility issues would not be right handed Hence in calculation of the far field x axis and hence 0 is actually inverted see the dotted axis XLVIII Modeling Bulk Acoustic Wave devices EM3DS allows the coupled acoustic em analysis especially developed so far for pure mode bulk acoustic wave resonators 106 In order to perform this kind of modelling you have to create an Acoustic Material Analysis form This may be done either from the popup menu in the Data Browser or from the main menu Tools E Acoustic Material Analysis 1 L al 2 063e4 3200 E Ber 17763 0 O 1e 6 1 5600 6340 3 55e7 2500 7 07100 1 05e 2 8 Add Material 2 0b3e4 3195 2244 E beF 17763 0 O 1e 6 l Delete Material 3270 11000 35970000 0 2e 6 1 gt comments Link to Electromagnetic analysis Lumped Elements Analysis Assigned Variable Permuttivity EZnO_FBAR45 sard5e6 Sif Assigned Variable tand TZn0_FBAR45 mz
56. specified the default planes are the ones of the ports Results calibrated at port plane will ever be available along with the ones at the specified plane Calibration is necessary to remove the effect of port discontinuity In a 50 Ohm microstrip line this is roughly 0 1 pF shunt capacitance While such a capacitance may not be important for some electrically large structures such as filters of switches in actuated position in our case it may be even larger than the bridge capacitance Hence calibration is mandatory If you want to displace calibration planes appearing as green lines you can either double click over the port or access the calibration plane from the popup menu In our example we ll leave the reference at the port plane Note that via ports and internal ports are not calibrated in this version The structure is now ready You can see in the 3D window how it appears By dragging the mouse over the 3D window you can rotate the structure and by accessing to the popup menu you can zoom in and out the 3D window All you have to do now is to select the General panel and click over the Go button Or menu Action Computation or simply press F9 In versions up to 7 a warning message is displayed the number of required modes to build the solution has not yet been selected In version 8 and above a checkbox in the Substrate Information and General Options namely Always use suggested values allows to skip
57. structures e g striplines If this is the case one should either resort to Ny gt 1 or write his own frequency dependent resistivity remind EM3DS allows to write parametric expressions when defining the structure Finally we have seen that there are cases such as the via contact which may require Ny gt 1 even at low frequencies As a general rule Ny should be greater than unity whenever variations of the current densities along the conductor thickness are expected The problem about the parasitic capacitance may be solved by using 3 possible approaches l By raising Ny the number of y subsections is available when defining the composition of the dielectric stack The possibility of defining non uniform vertical slices provides one more tool to circumvent such a limitation 2 By evaluating the parasitic capacitance and by manually removing de embedding such a capacitance the user should build up a structure involving only the junction and try to evaluate the parasitic capacitance Once the capacitance is known a serie negative capacitance may be added to the network in order to cancel out the above effect see fig below 14 DUT Network parameters Calibrated net If the whole via has to be manually calibrated the user can analyse the via and connect the resulting network as a Negate network to the network resulting from the simulation of the whole structure by using the embedded linear circuit simulator of EM3DS 3 mos
58. the process t Ide W Remember this priority C Moral i High AE C Automatic selection m E e Set Priority lw Auto Corect calibration at resonances f Cholesky Solver f Same enclosure as Device Under Test C Gauss Solver Use SrmartFit as default Show Panel for Advanced setting Computation Preferences Solvers Cholesky Solver this is the method used to solve the final system Is the faster and lighter one even if in order to make faster the solver the number of controls is reduced to a minimum It works only for reciprocal structures when modeling active devices EM3DS will load the Gauss solver regardless the user s selection If this solver fails the user can try with the alternative Gauss Solver Gauss Solver Its is a robust routine but much slower and heavier than the previous one For complex structures it may be several times slower than the Cholesky solver and the peak memory occupied may be as high as double of the one needed by the Cholesky solver Use SmartFIT as default if selected any new project will automatically invoke SmartFit when running an EM simulation Box Size for calibration standard select the default settings for the calibration standard needed when de embedding a simulation at the port plane See Standard calibration for more information Same considerations apply for Auto Correct calibration at resonance Show Panel for Advanced Setting if selected a panel is shown this has to do
59. the right expansion functions Continuity violation has very evident effects nearly no signal transmitted e g S12 nearly zero a null over the contact plane in the graphic of currents is apparent etc so that you can easily locate and fix the problem About the previous note it is easy to explain why the problem may occur Let us consider the following figure X Conductor A Conductor B 21 Fig 25 Two conductors are in contact no overlap in spite of this results seem to indicate no contact This happens as conductor B has only Jx while conductor A has only Jz Let us suppose that conductor B has no z edge and no other z mesh line and dually for conductor A This may happen e g because either you have not checked Add Edge Mesh z in the Mesh Options of conductor B or its Distance z value is too small so specifying a distance that can not fit into the shape Up to a certain extent the mesh algorithm inserts any way the mesh line in the middle but if the conductor is very narrow with respect to the specified border ratio the border mesh line is suppressed According to the previous explanation conductor B has no Jz while conductor A has no Jx Generally this fact would be acceptable as conductor B is narrow in z while A is narrow in x However this way no continuity is enforced and the conductors behave as being close but not in contact the above mesh is unable to model current turning at the edge A solution is to
60. this message and EM3DS will automatically perform the following steps Choose yes from the dialog and the project data window is once more displayed Select the button Use Suggested Val An additional recommendation there is the panel Number of involved modes These are the modes used to build up the asymptotic part of the Green s function Strictly speaking the engine will use the number of modes selected above only at the first frequency point while exploiting the number entered in the Number of Involved modes at any other frequency This is what makes EM3DS so fast This number is usually very small independently from the aspect ratio There is a suggestion also for those value and you have to manually enter a number slightly greater than the minimum suggested e g if suggested are 3 for x and 3 for z enter 5 and 5 If however the structure involves quite lossy substrates the suggestions may be currently underestimated and a good rule to get broadband results is to with a value significantly larger than the suggested one e g for a suggested minimum value of 3 use 8 or 10 Typically this correction is necessary for substrate with losses larger than 0 01 S m 43 In our case we have a substrate with conductivity 0 033S m so well in the range where some care has to be used Set the involved modes to 8 in x and 8 in z directions Substrate information and general options BHA Comp options Enclosuredielec
61. walls are only shown if Show WR Walls is selected in the 3D view Keep Ratio allows seeing the figure in its real aspect ratio while otherwise size is automatically scaled to fit the window Real Time Refresh allows to update in real time the image when rotating the structure This can be a slow operation in some old computer in such a case disabling this option may be useful 99 D r f Mag Rotate view zoom view bY mouse i zoom In Ctri h zoom Ck Chril 0 Move view Auto Rotate Ctrl F E Draw Ares no action on view i 5 Heal Time Refresh Copy View As Metafile SS Copy View 45 Bitmap ctrl E AEA Auto view Set Magnification Factor s pgrammi ME MR esearch E MaD Background Color Save view to File 2D Graphs gee ey gp om 30 Graohs Fig 100 3D View By the editor View or by the popup menu in the Data Browser you may also create very special 3D views the actual look of the structure being edited These additional windows include visual processing and rendering very effective for presentations but hardware dependent they may not work well on all graphic cards Current densities may only be displayed over 3D views with rendering The 3D view can be exported to file Save View to File either as bitmap or Windows Metafile It can be copied Copy View into the clipboard as metafile Sometimes a real structure may have dimensions
62. with layer 3 where the passivation substrate is being a substrate whose thickness is very important it must be a via layer hence an even index layer Consequently we open the Substrate Information window and we add before layer 3 a dummy empty layer say 0 01lum thick actually being an odd layer its value will be zero so for any practical purpose it does not play a role in the simulation as far as we do not introduce objects in it vt j ari 5 a ae Substrate information and general options Comp options Enclosure dielectrics JLISSS ALES SLL Dielectrics Parameters for the new Layer Layer 0 ayer 5 path layer Dielectric permittivity fi Bulk conductivity S m fo tand 0 0 Help Magnetic permeability fi Where To Insert Layer thickness um fo 001 Cancel ddi Layer 6 via layer Add new layer bottom F Delete Layer j Ok Top wall C Perfect conductor top Before Layer C After Layer Pl NOTE The layer you are editing has an odd index in 2 5D mode layers having odd index have ZERO THICKNESS Hence you can either use them as dummy layer as they have no effect remember to delete dummy layers if you switch to 3D mode or to iii C Approx Open top Material Infinite Waveguide Fig 54 Layers in 2 5D mode a planar layer 46 Being a dummy layer its permittivity and physical parameters are not relevant but we can
63. 0 IX Mesh options things to know for an efficient use Of EM3DS ee eeeeeeeeeees 22 To Probe Further what mesh cells are used fOP cee eeeeeeseeseeseeeeeeeeeeeeeeeees 26 X Working with non Manhattan polygons sssssssseeeeeececcceeeeeeseeeesssssseeeeeeeeees 29 To Probe Further How polygons are meshed cccccccccecesenssssseseeeeeeeeeees 31 PIRS a5 cose eeisesontiso E EE A E EET 31 PU e E EE E E EAE AE AE N 31 PE S en o a e E A E J2 PIRLO e E E E E E E E 33 a a E E 33 AVIL MOm ing AS esiin a e a E 34 XVII A simple step by step example a MEMS SwWitCch esssssssssssssesesereessssssssssssees 35 XVIII Dielectric Bricks and resonators material specifications sssseeeeeees 47 ALA DOS FCS acdc wszctccn ene senteratanvesuewseonndewanectnenenotedenseetueue Hw sdewsexeweues 50 XX Asymptotic Estimator saving large amount of time with limited or no loss of NE T T sca pect arcs den E E ies TE ease E I T TT 53 A Eveni ster Smaa T erari EERE TERE 54 AAH Automatic De EmDed rsrsrsr ereenn ri Erann EC EEEN 54 To Probe Further Meaning of error network file 0 0 0 0 cccsssssseeeeeeeeeeeeees 57 XAH Wy ave side cOMpPONEMS ceasar pani EN EE E E 58 XXIV Mul mode Waveguide calibrations adna 60 a PO EO a T tase E E E E E O A 62 XXVI Post Processing Diferential MOS vacinecsnerdsndsnacascchaasduncanatestrannedandss e 65 ee e e a T E ee E E A soe dees eeeaoaees 66 AA V UL Macromodel DONE sciri kai e O ae
64. 0 Note extra zero field will always show two decimal places 00 006 00 01 Note extra Os tor right of decimal point and rounding to two decimal places 74 To allow different formats for positive negative and zero values the format string can contain between one and three sections separated by semicolons One section The format string applies to all values Two sections The first section applies to positive values and zeros and the second section applies to negative values Three sections The first section applies to positive values the second applies to negative values and the third applies to zeros If the section for negative values or the section for zero values is empty that is if there is nothing between the semicolons that delimit the section the section for positive values is used instead If the section for positive values is empty or if the entire format string is empty the value is formatted using general floating point formatting with 15 significant digits General floating point formatting is also used if the value has more than 18 digits to the left of the decimal point and the format string does not specify scientific notation The graph on the screen may be copied into the clipboard as Metafile or as Bitmap in the first case it may be edited by tools as Microsoft Word and when changing its size no loss of details occurs in the second case the graph is stored bit by bit The graph may also be saved as
65. 02 XLVI Antenna modeling eee eeesesssssseseeerreressssssssssssssssecccreeeesssssssssssseeccrreeeessssss 102 XLVII Modeling Bulk Acoustic Wave CeVICES ssseeceececcccceeeaeeessssseeeeeeeeees 106 XLVIII Creating queues of simulations the Batch Planner et eeeeeeeeeeeeees 108 XLIX Accessing and using EM3DS from AWR Microwave Office eee 109 Me oe arc tise EEEE boat eter SEEE EE EEE 111 Appendix H Solyer Mess AO CS xed ince ostcusaenenotscintscnnuneddansearicesachelicnsanetccwegsetpeesvesiace 115 NOTE areare een eeeteien unesaeud wade EE E EE 120 PU T i AEI E A T A TEE A AT A IE E T ET T 121 122
66. 66 AALA O TEI ccoir E EE S ESEE S 67 A ITD a E E vesoeu seb Gpceee ne toe tes eeate vse ees 68 AAALP anoe S mOi e basser se dan bab dehnenaunecnabaunenees 69 XXXII Post Processing displaying network parameters and using the Data Browser e E E A 70 To Probe Further The Touchstone Data File Format eeeeeeeeeeeeeeees 78 XXXIII Post Processing Creating Custom Measurements csessssssseeseeeeeeeeees 80 XXXIV Post Processing Time Domain in EM3DGS i eeeeeeeeeeeeneereeseeeseeneeees 80 XXXV Post Processing displaying volume current distributions in surface plots 81 XXXVI Post Processing displaying volume current distributions in contour plots 83 XXXVII Post Processing Magnetic Force DeMnsIty ccccccccecccseeceeessesseeeeeeeeeees 86 XXX VIII Post Processing Far Field 3D View ccccccceecccccsseeessecsseseeseeeeees 87 XXXIX Post Processing Broadband Spice Model Extractor eeeeesseeeeeeeeeeees 88 XL Post Processing Linear Circuit SI AGO icc scnssncescussnecseesnnesssecsswensdienewseenweseuss 90 XLI Post Processing Object Oriented Pascal Script cccccccccccssseeesssssssseeeeeeeees 93 ALU PANE eres x wsandiaenenaa ronan eecedsiansesaaeaancnadnctmeneseousosatieenwsanaes 99 Pe TM AI V E EA A E acer 99 XLI Project Description sassis nantia a aeaa 101 XLIV Translators importing and exporting DXF and GDSIHI files 101 XLV Using EM3DS with command line files that can be associated to EM3DS 1
67. Computation and a great number of modes that will affect nearly only the first frequency point if the asymptotic estimator is enabled If e g the box is mm wide and two vertical mesh lines are only Sum apart building the Green function will require roughly 1mm 2um 500 modes in the x direction In order to give an idea of what should be considered sound and what probably wrong About unknowns related to the number of mesh cells 200 unknowns are a small system 1000 unknowns are a medium system 2000 unknowns are a large system and 5000 unknowns may be to date hard to be solved in a PC the number of unknown affects in the same way the analysis at any frequency point About modes related to density of the mesh cells 30 modes in each direction are a small number 100 modes are a medium number 200 are a large number 400 starts to be hard to be solved the only advantage being that the computational effort is limited to the first frequency point 23 EM3DS Electromagnetic 3D Solver File Edit View Settings Action Tools Window Help Editor Sela Rendering 1 aaa General Draw Edit tools Post Processing Close Polygon ESC Delete Last Point Dimension and Position izi Graph 1 Resistivity Material specif ig as Specify de Embedding plane 6 3D Graphs Bring to Front i Send To Back i Current Density 1 Mirror x Pa i I Editor 3D Views Mirror z Highlight contact shapes l Standard 3D View
68. Draw Axes 4 POLO OS OS EGOS E EE EEA a Plot Mode rotate Keep Ratio 7 DA ESIES EE ELIG IAN ee a O pee GA E lt Data Browser D r A Frere pA kapau T Taa AAAA p gt aS DP PS w aaa SS 2 PAD DPT a T a h E S in ao k h a 4 4 4 L gt 4 x EEF D DATASAWA COMSEM Socki Current Density Rendering 1 Ul ot Mode rotate wy Wey ey 3D View Renderir Layer1 NS Layer 2 gt Layer 3 Z N Layer 55 Layer E 20 View Renders x 156 um z 308 um Editing mode 3D Mode i BS uu 2 iil gt Fig 53 Screen shot several kind of current visualisation Now you have correctly simulated and processed your switch in the 3D mode Yet we have seen that most of the 3D features were not used as we have left thin most of the layers witnessing that in this case a 2 5D mode would be ok We can run the simulation in 2 5D mode very quickly and just a few modifications are necessary to fit into the conventional assumption than odd layers are infinitely thin So we have to add some dummy empty and thin layer here and there to ensure that the geometry is the one desired As first step let us check Settings 2 5D mode Immediately any 3D window is updated to highlight that all odd layers have virtually disappeared Now layer 1 odd is where is the bridge so it is ok it is a thin conducting path The same for layer 2 which is a via layer and there we find the anchors The problem is
69. Ext Data Fig 40 Size of the box Check the Metric checkbox Select units as um enter the horizontal x dimension 160 the vertical z 420 Note that in any point you can enter expressions instead of numbers e g in x 280 160 where needed If this was an antenna and we were interested to the antenna plots we should have selected Add Sense Layer from the main menu Action but this is not the case You can find more information in the Antenna section 2 While EM3DS does not require the design to fit into a grid a grid is available in order to simplify entering the structure Hence select the Drawing Edit tools panel and click over the button Fit in Grid 35 lit tools Post Processing Flot Mode rotate E L Data Browser I Fit in Grid Show Grid Mum cells Hum 2 cells Cancel Fig 41 Grid Enter e g 80 cells for x and 105 for z this will only affect editing and you can change these parameters as you want during the editing process 3 EM3DS supports two working modes the full 3D mode and the 2 5D mode default In the remainder of the example we will first consider the full 3D mode and then see what has to be modified in order to correctly run the example in 2 5D mode The 3D mode assumes that each conductor has its thickness which is the same of the layer in which the conductor is placed Hence there is no distinction between normal planar conductors and via conductors i
70. Highlight Contact Shapes in the pop up menu gives an answer to this problem by verifying if several items visually close are or not in contact In fact sometimes the round off on the screen may give false impressions Hence in the present version no overlap is needed even if overlapping is possible Overlapping usually results in a denser mesh that may or may 111 not be desired by the user The older editing mode namely the automatic resize to overlap may be enabled if desired by selecting this check box Note the resize to overlap mode should be selected when creating your project Avoid to create a project partly developed with this selection enabled and partly disabled the editor may not be able to reopen calculated data Create a 3D View with rendering for new projects Requires to create automatically at least one enhanced 3D View when defining a new project Change Background Color modify the editor background color Number of Undo Levels Storing information for roll back undo may require some time so that in complex structures it may be necessary to reduce the number of undo levels in order to keep editing fast enough The user can select the number of undo levels according to its exigency Issue a Warning before Running a Script if a global script is defined in EM3DS see Tools Script Editor issues a warning before running it Preferences Editar Computation Mesh solver Box size for Calibration Standard Priority of
71. In x Procedure CACOS x complesso var y complesso y arc cos x A static matrix of complex numbers is also used to exchange results with the solver TSCOMPLEXARRA Y array 0 maxstaticsize of complesso TSCOMPLEXMATRIX lt array 0 maxstaticsize of TSCOMPLEXARRAY The constant maxstaticsize is available to the user Also a constant indicates the script library version namely LIBRARYVER which is a string Library will be often enriched with new functionalities A number of functions allow to interact with the solver Function FrequencyIndexExists f double var index integer boolean After a calculation if one passes the value of the frequency GHz as f the function returns in index the position in the solution array the function returns FALSE if the solution wasn t calculated f Procedure LoadNetMatrixFromFile FileName string var errorString string Load in EM3DS Touchstone file named Filename ErrorString is empty if successful otherwise it returns an error message NOTE in order to make accessible to the user the loaded file Procedure LoadNetMatrixFromFile should be ALWAYS followed by the instrucion AddSourceOnList Procedure AddSourceOnList namesource string Adds a previously loaded Touchstone file named nameSource to the list of available external file in the Data Browser and in any chart ALWAYS needed after loading a Net matrix from file Procedure SaveTouchStoneFile FileName string AlreadyOpen boolean KindMa
72. Layer thickness mm oC Layer names comment Gass number of y subsect 3 Hon uniformity Factor 1 e d Fig 9 Setting the properties of a dielectric layer This same window can be accessed from the main popup menu of the editor Edit Properties of the current Layer The meaning of the items appearing in that window is straightforward Dielectric Permittivity relative permittivity of the selected layer Bulk Conductivity S m conductivity of the selected layer S m tand dielectric frequency independent losses 1 Magnetic Permeability relative permeability of the selected layer u In the 2 5D mode those parameters are not used for layers having odd index and they appear gray nonetheless setting sound values is recommended in order to simplify a possible switching to the 3D mode Note the above parameters dielectric permittivity and conductivity refer to the host dielectric layer and NOT to the conductors or the dielectric bricks defined within that layer The properties of the latter are accessed by first selecting the object via mouse and selecting Resistivity Material specifications from the popup menu If thick conductors are defined in that layer the dielectric layer properties specify the properties of the dielectric outside the conductors Any parameter may involve expressions Reference to frequency may also be inserted in material definitions by using symbols f or F in the expressions F is in Hertz F
73. Microwave Office The structure can be further edited directly in EM3DS by selecting the popup menu Open in Native Editor A few notes should be considered mesh options in EM3DS are still basically different from the ones of Microwave Office mostly because in EM3DS there is not grid constraining the design A good effort has been made to map some of the options of Microwave Office into sound mesh in EM3DS and more work is in progress While meshing structure only involving Manhattan polygon should be already robust general non Manhattan or curved structure should be checked for correct mesh into EM3DS Microwave Office is 2 5D so the structure is imported in 2 5D mode as default If and when switching in 3D mode check if there is any dummy layer to be deleted Moreover if there are via connection it may be necessary to set slicing possibly non uniform for layers hosting quasi planar parts Resistive conductors in Microwave Office MWO are so far handled by means of surface impedance When reading the structure from MWO Em3DS assigns a fictive thickness to planar conductors and a resistivity ensuring the same DC resistance If and when switching to 3D mode be sure to assign the correct physical resistivity Qm to the conductors in EM3DS Refers to the AWR s user s manual for further information about Microwave Office 110 Untitled Pr New EM Structure Enter a name for the EM Structure EM Structure 7 Select a simulator
74. NU TMAINMENU TMENU TMENUITEM TSTRINGS TSTRINGLIST TBITS TSTREAM THANDLESTREAM TMEMORYSTREAM TFILESTREAM TDATETIME TMSGDLGTYPE TMSGDLGBTN TMSGDLGBUTTONS And the functions function MessageDlg const Msg string DlgType TMsgDlgType Buttons TMsgDIgButtons HelpCtx Longint Word It includes all standard Pascal types and general routines Additionally some strings date types and utilities function EncodeDate Year Month Day Word TDateTime function EncodeTime Hour Min Sec MSec Word TDateTime function TryEncodeDate Year Month Day Word var Date TDateTime Boolean function TryEncodeTime Hour Min Sec MSec Word var Time TDateTime Boolean procedure DecodeDate const DateTime TDateTime var Year Month Day Word procedure DecodeTime const DateTime TDateTime var Hour Min Sec MSec Word function DayOfWeek const DateTime TDateTime Word function Date TDateTime function Time TDateTime function Now TDateTime function DateTimeToUnix D TDateTime Int64 function DateToStr D TDateTime string function StrToDate const s string TDateTime function FormatDateTime const fmt string D TDateTime string Complex numbers are handled via the COMPLESSO type and a number of functions are implemented Type COMPLESSO Record Re double Im double end 95 Procedure CONIUGATO C1 Complesso var C2 Complesso in C2 the complex conjugate of C1 Function MODULO var C1
75. S GB Traces Trace 1 v De Embedded From Port Data Source Curent EM Simulation M Reference to Port j Use MacroModel as source x 2 9688867 GHz y 10 235309 Fig 79 Displaying network parameters T2 If a macromodel is available when the data source is the current EM simulation you can select Use Macromodel as source and the macromodel response is displayed The macromodel response is updated in real time when you modify the macromodelled parameter The response of the macromodel for the current parameter can be exported by the popup menu Export Macromodel simulation to file creating a standard touchstone file Note that if using the macromodel the De embedded checkbox has no effect Link to Data Sources and not data sources are saved within the EMS file if the editor is unable to find a given path it looks for the requested file in the same directory of the current EMS file From any chart you can create an Interpolated Data Set Add Interpolated data Set namely a rational interpolation of the input data the new data set is added to the list of Data Sources and saved in the HD with unique name See the paragraph about SmartFIT for more information By clicking over the menu item Set Axis Limits it is possible setting the vertical y and horizontal x axis limit of the plot Bis Limits OO OOOO Y Ax Pi ARI M Fitto data Max 41 OF F5 Min fo 0225 Pore Help F1 Fig 80 Axis Limits B
76. View Rendering 1 ee General Draw Edit tools Post Processing r LL Plot Mode rotate sity Se Ce ae ee ee Sal sity Rer EE TestDREMS Current Density 1 Plot D View gt endering t ii Fig 58 A microstrip fed dielectric resonator igs lt XIX Modeling Active Devices Si N passivation Ti Pt Au Gate oe N GaAs Contact Layer LLL LLL Nt AlGaAs y AlGaAs x Spacer aAs buffer 2DEG Fig 59 Schematic view of the cross section of a single mushroom AlGaAs InGaAs pHEMT active element 50 Depleted region passivation Ti Pt Au Gate N GaAs Contact Layer Source Contact Drain Contact LL N GaAs y i ia yy yy active layer Fig 60 Schematic view of the cross section of a single MESFET active element In EM3DS volume currents model conductors dielectric bricks and active regions The very nature of such currents is specified by imposing Ohm s law to be satisfied within the conductors the Two Dimensional Electron Gas 2DEG in HEMTs and the channel current in the epitaxial layer in MESFETs to be linearly controlled by the vertical y directed field underneath the gate electrode Note that the second constraint yields a fully electromagnetic treatment of the active part Applying these two constraints yields the integral equation to be solved for the complete current distribution
77. Whenever the Asymptotic Approximation is used the argument of these functions is fixed at the lower frequency of analysis so partially loosing this attractive feature However the reliability the speed and the robustness of the Asymptotic estimator largely compensate the above drawback and its use is strongly recommended The Discard Asymptotic Info button may be used in order to discard information stored when we believe that the information is unreliable This may happens e g if we start an analysis but we stop the computation while filling the Green matrix actually its discretized counterpart the MoM matrix at the first frequency point Draw the structure The tool provides a simple editor by selecting the menu Action Add conductor or by clicking over the corresponding button on the toolbar the user can draw rectangular shapes Non Manhattan polygons namely polygons that cannot be described by drawing rectangles may be drawn by the Add Polygonal cond menu while circles are added and handled as polygons by clicking over the Add circle button Circles are approximated by polygons a better approximation usually means a higher computational load Consider that there are a few cases where such a high 17 degree of approximation is actually needed e g dielectric resonators Also Circular Spirals Curves Slanting lines and Rings are available As to the rectangular shapes once selected Action Add conductor the top left corner is fixed
78. Ytest y4p is 57 DLYtest y4p that is odd ports on the left hand side and even ports on the right hand side By connecting port 1 of DLYtest y4p to port 4 of the output network Ytest y5p and port 3 to port 5 DLYtest y4p the effects of the embedding is negate removing the discontinuity and the lines up to the reference plane so that looking into ports 2 and 4 of DLYtest y4p one obtains a de embedded measure The same holds for DRYTest y2p and to DT and DB files There are a few exceptions to the above numbering occurring whenever during editing ports are first inserted and then removed XXIII Waveguide components EM3DS allows modeling a class of 2 port waveguide components The purpose of this section is to show how to model waveguide components by means of a simple example a single cavity waveguide resonator with inductive irises In order to draw the structure you have to consider direction y namely the vertical one as the propagation direction Irises are drawn in the layers of the structure Layer i ee Layer i 1 ayer i 2 Fig 64 Drawing irises in the multilayer waveguide The structure has to be excited A possibility is a couple of strips extending up to the walls placed at the bottom and the up sides respectively of the structure The strips mimic the way you probably would do the measurement of such a device the network analyzer would be connected to the waveguide component by means of a couple of coax t
79. a panel with parameters is available Variables Parameters Seles Varable parameter Expression alue Load Update Variables Fig 5 Variables There you can define global parameters You can use them to define the geometry and the position of your objects Reference to parameters is saved when defining geometrical features and properties of materials while elsewhere EM3DS substitutes the parameter with its numerical value automatically The parametric definition is enabled only after clicking on Load Update Variables As an important note imagine that you define a coordinate of a rectangle to be a parameter x If you change x the rectangle changes its position However if you force the position of the rectangle either by mouse or keyboard arrows the reference to the parameter is lost This is important when defining complex shapes such as spirals or bends they may be completely parametric but it is necessary to specify their position via coordinates not by mouse or parameters are converted to numbers VI Getting Started Using the EM3DS is rather simple The purpose of this section is to describe the most important steps you have to follow in order to edit and to run a standard simulation Consider to use one of the tutorials to quickly learn how to set up a simulation Choose the box dimensions your structure is enclosed in a metallic box or more properly a rectangular waveguide the walls forming the four sides of your workspace
80. ae From file Ha Save Formulae to File Copy view as metafile Hz Arn Copy view as bitmap 0 Save view to File Font Display Set up Panel Additional Parametric Definitions Display Assigned Field Background color Ho 1 Animate Show Legend w Show Values w Show Magneto static Field Assign Panel Help Expressions may be parametric and the user can define parameters in the Additional Parametric definition box Expressions can make use of a complete list of functions see Appendix for built in functions They can make reference to x y and z as spatial co ordinates in meters X 0 Z 0 is the left hand upper part of the screen and of the box Y 0 is the floor of the box where usually ground is located Note that all quantities in this window are metric and not imperial units The entered formulae may be saved to text files by the popup menu Save Formulae to file Being text files they may also be edited externally Formulae may be reloaded by clicking over the item Load Formulae from file Any time the user leaves an edit box the graph is updated the tool just calculates B uH by using the magnetic permeabilities of the dielectric stack and then calculates F JxB N m where J is the RF volume current distribution calculate from the em analysis This operation is done on the floor of the selected current slice The assigned magnetostatic field may be displayed by selecting Display Assigned Field in the Assign Magnetostatic Field pa
81. al Eal ay L el Substrate information and general options Sele Comp options Enclosure dielectrics Dielectrics Layer 0 no object can be placed i Layer 0 Layer 1 WN Layer 2 Layer 3 Layer 4 E Layer Parameters Dielectric permittivity his 0000 Layer 6 C Bulk conductivity S m 0 33 Si Parame Data about Layer 6 tand 0 Hel Add new layer bottom thickness 4 000E 2 0 E 2D Gre uh Magnetic permeability Delete Layer ae ea r 1 ie tep Layer thickness um 400 Insert new layer tand 0 000E 0 Se mag perm 1 number of y subsect fi Editor lt Ok Ny 1 Circuits Top wall Bottom M Non Uniform y subsections Perfect conductor top C Perf Tools C Approx Open top C App a Ei Ext De fa hAstasrial flisfuaita tfan ela fa hast Fig 44 Layer setting Add another layer having relative permittivity 3 9 and the thickness 0 4 um this is the silicon oxide layer added to avoid contact with the silicon buffer Hence add the last layer permittivity 11 9 bulk conductivity 0 033 S m and thickness 400 um this is the silicon buffer The dielectric stack is now completely specified You can close the project data window You should have now 6 layers appearing plus layer 0 layer 0 is over your structure you cannot place objects in it but it is the only one that can safely assume O as value for the thickness which means it is removed 4 Now we have to enter the st
82. and Y7 for the four port are Yo LY O Yoa 2 Vee y Y 2 fori j 0 1 0 where _ tl fia ht 1 fiz The symmetry wizard will automate this kind of calculation for an arbitrary number of ports Note that you have to use PMC and not Symmetry Plane as boundary condition in order to have correct results If mesh of the original structure and of the two half is identical results will be completely identical If you note any difference this is usually due to the fact that meshing can change according to the different size of the side walls In order to invoke the symmetry wizard you one can either click on the main menu Tools or select the button from the toolbar or from the tools icon in the data browser 21 Sal Parameters 2D Graphs Post Processor for symmetric structures MEM Research Symmetry Wizard Ji 3D Graphs B Editor 3D Views Welcome to the MR Wizard for post processing of symmetric structures a fi Circuits i m py HAE pecial Materials Symmetry Wizard YV wa n a a per Differential ports ai Est Data Files lt iili This Wizard will guide you through steps needed to rebuild the complete network parameters of a symmetric structure starting from the knowledge of networks evaluated by replacing by a Perfect Electric Conductor PEC or odd excitation and by a Perfect Magnetic Conductor PMC or even excitation the symmetry plane You will only need t
83. and MEMS design approach 1 is generally needed Some tests over benchmark structures will give you the necessary sensitivity to select the best way Select the Frequency Range EM3DS is a frequency domain tool basically providing network parameters over a given set of frequency points Nonetheless it provides several time domain tools that will be affected by your choice of frequency points see the section about Time Domain for more information In order to set up the frequency range over which the analysis will be performed you have to access once more to the Substrate Information and General options window by clicking over the Analysis and Substrate Settings button or over the menu Settings Analysis and Subst Settings This time we select the Comp Options panel default The window appearing is shown in figure 3 There you can set the first and the last frequency points to be analyzed The parameter Num Points indicates how many points in the given frequency range are calculated the step is calculated and displayed on the right upper corner of the window Actually there is an additional device SmartFIT SmartFIT is an adaptive rational interpolation If you select to invoke SmartFIT EM3DS will decide the frequency points to be evaluated and finally will generate a complete response in a number of points decided in the SmartFIT Dialog menu Tools SmartFIT 15 interpolation SmartFlT options Frequency Interpolation post pro
84. and every related phenomenon provided that Ny is enough There is a tutorial about using the 3D mode and one about meshing also describing and demonstrating the issue here described FAQ 2 How do I select the number of subsections First of all this parameter has only to be settled in the 3D working mode in the 2 5D mode currents are either transversal x z or vertical and transversal currents are only surface currents conditions requiring slicing do not occur at all In 3D mode when selecting a number greater than 1 EM3DS acts much like the conductor being sliced in thinner parts Generally just once slice hence 1 default is necessary owing to some variational properties of the solver However more slices are needed whenever thick conductors where thick may simply be a few microns or even micron are in contact with conductors in other layers like e g with vias producing a sharp vertical discontinuity see the following To Probe Further 2 section Sometimes more slices are needed for coplanar structures having very small interelectrode spacing in order to account for the vertical current gradient Finally slices are needed in order to correctly modeling losses at higher frequencies skin effect in this case rule of thumb is that ratio t Ny where t is the layer thickness and Ny the number of subsections be roughly equal to the skin depth Note that rising this number the computational load grows very quickly The best idea is
85. ape will delete reference to the related parameter By the way let s click on the parameters button or directly in the XY icon appearing in the data browser and define some variables 39 Variables Parameters E Ed Varableparameter Expression alue i Load Update Variables Fig 45 parameters use the keyboard arrow to navigate in and add rows for new parameters If parameters are used you will later be able to use either the Optimizer or the Tuner menu Tools Just as example we have only defined 2 variables gw ground width sp line spacing but consider to parametrize every geometrical property of your objects Now draw a rectangle and set in the panel 160 and gw um while the top left corner to 0 0 click over apply button The structure is updated and the right bottom vertex is also calculated Click over oe COM EM_Socket MEMResearch Source EM3DS 7 Wntitled EMS O X lt 3D View Rendering eneral Draw Edit tools Post Processing Conductor Dimensions Dimensions k 160 Dx f0 Plot Mode rotate z gw Dz fo Data Browser __ Displace i Position Top left corner Xi ooo z o o Mesh Op P Parame Right x 160 Resistivity 2D Gral Bottom z 100 n 3D Gral Units fum 7 V Metric Round Dim Fig 46 Parametric definition of the width Note that you can reference to variables like gw not only when defining geometry but also anywhere in the editor
86. ar by selecting Force skin effect we require an approximate accounting for such an effect The above resistivity scaling will be needed only by objects in layer 1 We need to add other two rectangles we can simply copy and paste the previous rectangle so as to avoid to specify every time its parameters To this aim simply click over the rectangle select copy or CTRL C then paste or CTRL V and place where you want the rectangle You will note that even if you displace shapes either by the keyboard arrows or by mouse your reference to the variable is not lost this is only because the variable is used for the size and not the position Reference to variable is only lost if your editing conflicts with requirement imposed by your parameter Edit its dimensions and set them to 80 x and 220 z while selecting as top corner 40 in x and 100 in z Repeat those steps once more editing one more rectangle with 160 x and gw z microns as dimension and 0 x 320 z as position This way you have drawn the bridge with its upper support EM3DS Electromagnetic 3D Solver File Edit View Settings Action Tools Window Help v EM3DS loaded D DATA AWR COM EM_Socket MEMResearch Source EM3DS 7 MEMS Tutorial EMS Be 3D View Rendering 1 General Draw Edit tools Post Processing Plot Mode rotate l Data Browser a Parameters 2D Graphs 3D Graphs l Se SP BE 7Sans i Editor 3D Vi
87. at least 1 port is attached to a conductor it is possible to specify the distance of the de embedding reference planes from each side of the box left right top and bottom The calibration plane is available only if the automatic de embedding check box in the Project Data window is selected Specifying the distance of the de embedding planes at each side of the box left right top and bottom is only possible when at least one port is attached to a conductor The selected plane is displayed only if the automatic de embedding check box in the Project data window is selected If de embedding is selected the additional button De embedding line parameters is made available by clicking over this button characteristic impedance effective dielectric permittivity etc of the feeding lines are displayed If more than one edge port is attached at one side of a box the eigenvalues of the characteristic impedance matrix are calculated Those eigenvalues coincide with ZoEven and Zooaa for a couple of symmetric lines and are a generalization of these impedances in the general multi port case see See the paper On the Definition and the Derivation of the Characteristic Parameters of Coupled Lines and Application to MoM Analysis by Marco Farina Antonio Morini and Tullio Rozzi in the 2005 IEEE MTT S Int Microwave Symp Dig For more info 39 Also propagation constant and effective relative permittivity are calculated Note that in order t
88. can be settled in the Substrate Information and General Options dialog accessed via menu Settings Analysis and Subs Settings When a PMC is defined the structure is somehow duplicated so that fields are the same that one would obtain if the structure was mirrored with respect to the PMC 19 Mirror structure ARRAPAR AARAA AA eee FIIRT ASIII TITT FIRRA ITIITI PERERPIPERRA PEPEPEPE PLLLLILLELLEEL ELL LESS PLLLLLLLLILL LILLIES APLLEELELLLLELALLALLLE lt PMC Fig 15 A PMC mirrors a structure A PMC wall can be hence used to solve half of a symmetric structure Note that if a port is defined coaxially to a PMC network parameter Y would have a factor 2 of difference with respect to the parameters of complete structure owing to the fact that only half a port is considered in evaluating currents flowing In this case you can choose Symmetry plane instead of PMC as this will automatically correct such a factor An example will clarify i P2 Symmetry plane Pl Fig 16 use of Symmetry plane The example above top view shows how the symmetry plane works the two structures will give exactly the same S parameters or Z Y parameters while the one in the Right Hand side will require much lower computational effort If instead of the symmetry plane the user would have selected a PMC the two structures would have exactly the same fields but the network parameters Z Y would differ of a 2 factor as they would be eval
89. ced by the finite bandwidth used The stimulus impedance is always 0 Ohm while the load impedance can be modified by double clicking over the ports of your project and by specifying different normalization impedances See the previous section about Time Domain in EM3DS for more information In Frequency Animation the first 2D plot window of network parameters is brought to front and a circle over the plot indicates the frequency being displayed Steps Graph Options lets you select the number of frames that are used in the animation vs phase starting with the starting phase When more than one expanding function is used along the y conductor thickness direction in the current layer the user can select a Slice in layer Layer namely one of the slices used to subsection the conductor over the thickness The current distribution refers to such subsection so the user can also investigate e g details of the skin effect Slices are numbered starting from the floor of the conductor see also pp 5 6 Sa Current Density E Field 1 Sel Right click to hi Plot Mode Rotate Ports Layer Displayed Cuments E Fields Frequency Animation Graph Options Animation Sheps Shaina Pee Time interval f over Phase 36 30 Deg 0 fa i c 20 Stark Stop Points iw Kaiser Beta JG C Frequency 05 ns E How showing T Time ae Animate oy i Frequency domain Stimulus ulfl Fig 88 Surface graph of the volume current distribution
90. cessing only Hep Number of Interpolated paints E M Do not use SYO SmartFlT runtime frequency interpolation corector Number of Starting points Interpolated points in SrnartFitting minimum number of evaluated F zi 3 Max Rel Convergence Err Max Humber of Iterations Med a T Fast Interpolation reduced robustness Run SmartFlT simulation Fig 12 SmartFIT dialog The number of generated points is the one indicated in Interpolated points in SmartFitting Other parameters include the maximum Relative Convergence error the Number of Starting Points usually 3 and the maximum number of Iterations See the section about SmartFIT for more information Note that you can perform several analyses spanning different frequency ranges Results are cumulated until the structure or its mesh are modified This way analysis can be performed also for unevenly spaced frequencies Only one care is needed if you change the upper frequency of analysis EM3DS ask you if updating the mesh for the new selected frequency band if you select yes old results are discarded as well as asymptotic estimations see to Probe Further 3 Hence if you want to cumulate results you have to select no This is also true if you want EM3DS to keep in memory the calculated Asymptotic Estimation so as to speed up the calculation over the new range To Probe Further 3 Additional options There are also several other items that can be entere
91. couraged as the resulting mesh may not correctly account for the structure being analyzed Output Touchstone file this is the name of the standard output function no extension the EM3DS uses for the non de embedded raw network result automatically created for backup If Save EM computation is selected the current density distribution is stored in a binary DAT file You will need this DAT file in order to access to the calculated results If automatic de embed is selected EM3DS will enable specifying non zero reference planes for the resulting network parameters solution will be referred to these planes while any discontinuity due the ports and the lateral walls is removed by an automatic calibration procedure Whichever is the reference plane selected for calibration EM3DS will also make available results for reference at the port plane feature of ver 6 3 16 Substrate information and general options Start Frequency GHz fo Step 1 GHz Stop Frequency GHz z Hum Points 2o M Invoke automatically SmartFIT Num modes direct 6e Suggestion Num modes 2 direct AE no suggestion no suggestion Default Output Touchstone File no extension t indicated W Always use suggested values Define a Frequency List Suppress wideband Mesh W Save EM computation roo limit num modes W Automatic Deembed W Asymptotic approximation Help F1 W 25D simulation Involved modes direction 5 a minimum sugge
92. cy GHz Measurement To Port 1 fe Traces Untitled EMS W De Embedded From Port i nited Data Source Current EM Simulation Reference to Port Ww TOR Time Domain Time interval lo ns ns 400 Start Stop Paints Right click For additional menu View Stimulus W Kaiser Beta le Frequency domain Stimulus ulfl 1 xi 0 61646341 GHz y 035614591 Fig 83 Additional Time Domain Panel Here one enters the time interval the number of plotted points in time there are no restrictions By default the stimulus is assumed to be 1 over the whole frequency band if frequency points are equispaced this equivalent to a finite pulse whose width is determined by the upper frequency point 1 fmax and which repeats after a time correspondent to the lower frequency point 1 fmax However it is possible to enter any frequency dependent expression to create your own stimuli The actual stimulus is displayed when checking view stimulus A Kaiser Beta windowing is applied by default in order to reduce the ripple induced by the finite bandwidth used See the document the section Time Domain in EM3DS for more information A subset of the above commands are available for Smith Charts 76 Smith Chart 1 0 2 QOX 4dd Data Source Touchstone Filet b dd Trace TAF Edit Trace Properties Trace 1 l TH Export EM Simulation To File TRE Copy View to clipboard As bitmap Ctrl C Bes a Copy View as Metafile t Save view to File A Refre
93. d on the right hand side standard structure automatically built by EM3DS and not shown to the user If the automatic de embedding option is selected the standard not de embedded output file is produced and additionally other de embedding files are saved namely error networks representing a negated form of the dicontinuity feeding lines system including the overall de embedded results EM3DS directly connects the above networks and the user should not be directly concerned with above files this is done in the Plot Window menu View Graph or button Plot network parameters or select a graph from the Data Browser by double clicking over it where network parameters are shown De embedded network as well as the standard network may be exported by this window What the user should only be aware of is that when opening a pre calculated project including de embedding EM3DS needs file DLY DRY etc possibly created during de embedding procedure File DAT the distribution of the current density this file allow obtaining the non de embedded network parameters File EMS native file describing the structure it is the only one strictly needed to perform a simulation It is the only one strictly needed to describe the structure File DES description is an RTF file created by EM3DS where design notes may be stored File GOS Graphic Options Settings storing number and formatting of network graphs When
94. d by the same dialog window These are Num Modes in the x direction as said before in order to build up the electromagnetic solution EM3DS uses the modes of the waveguide enclosure More properly modes are used to build up a Green function a preliminary step toward the solution of the problem This item let you select how many modes have to be considered More modes generally mean more accuracy of course paying with longer running time at least at the first frequency point What determine the number of modes strictly required for a sound solution is the ratio between the enclosure dimensions and the smaller discretization cell namely mesh cell Mesh cells are individuated by vertical and horizontal mesh lines hence the ratio to be considered is the ratio between one of the enclosure dimensions e g the horizontal one and the smaller horizontal interval individuated from vertical mesh lines The Suggestion box indicated the number of modes according to Nyquist theorem the values are copied in the Num Modes boxes by clicking over the use suggested values button If the checkbox Always use suggested values default is used EM3DS will automatically load suggested values when running a simulation Mesh lines requiring more than 1000 modes are automatically suppressed By selecting the Suppress wide band mesh check box and by entering the new value in limit num Modes may control this suppression However the use of this option is strongly dis
95. d in the same plot Items in the setup panel are common to those shown in other plots of the currents Additionally number and position of the arrows is selected according to the num sampling cells A value of 20 for x for example indicates that a cell is a 20 being a the box size the viewer fits any object by cells with this size and in the middle of each cell places a vector showing direction and magnitude of the current in that point You can also see and create time domain animations of the current field distribution Menu is identical to what described in other current plots See also the section about Time Domain in EM3DS for more information or the tutorial about time domain 42 3D View Rendering Seles Plot Mode rotate Fig 93 Vector plot 85 XXXVII Post Processing Magnetic Force Density From the Data Browser you can select Add Mag Force A window similar to the one described in the previous section is created In this window a contour plot of the approximate body force distribution due to an assigned magnetostatic field is displayed The underlying assumption is that the assigned magnetic field is not distorted by the existing structure or that the expression the user inserts already takes into account for that Expressions for magnets having simple shapes are known The user inserts an expression for static H Assign Magnetostatic Field panel Assign Magneto static Field Hx Asm i Hy Am Load Formul
96. d surface plots You can also add advanced 3D plots involving lights and rendering very effective for presentations Note that this kind of graph strongly interacts with your graphic card and may not work properly in any PC Fig 89 Surface graph of the volume current distribution with rendering XXXVI Post Processing displaying volume current distributions in contour plots EM3DS adds one more representation of the current density namely a contour plot To this aim just select from the data browser Add contour Graph 3D or click over the icon if your have already added such a graph A window with the current distribution within the conductor dielectric brick volume is displayed 83 Fig 90 Contour Plot of the volume current distribution Currents are displayed layer by layer hence if layer 1 is selected only currents flowing across objects in layer 1 are displayed but if All layers is selected every layer starting from the lower one is displayed in the same picture Note that in the latter case if more slices are defined for a layer only the lower one is displayed In order to control the graphic appearance select from the popup menu Display Setup Panel Several parameters are common to the standard 3D surface plot see previous section By moving mouse across the area the current density value is displayed in the status bar Note this will not work if All Layers is selected Also a legend may be displayed by selecting Sho
97. data sources in any graph either rectangular or Smith Chart in the data source list where they can be plotted If an EM3DS project contains a circuit it is automatically reopened as far as the path is preserved or the circuit is in the same folder of the EM3DS project XLI Post Processing Object Oriented Pascal Script EM3DS implements an object pascal compiler with a reduced set of commands to write scripts namely macros to be executed to customize EM3DS or to iterate some process Scripts can be GLOBAL or LOCAL if local they are only loaded when opening a given project while if global EM3DS will always look for them A script can be AUTORUN select this option by selecting the icon in the Data Browser and right clicking in that case the script 1s immediately compiled and executed when the project is open or em3ds starts if global In any case a confirmation dialog is displayed in order to avoid execution of malicious software the warning can be disabled in the Preferences A local script can be made global and vice versa by simply dragging and dropping by mouse the relative icons in the data browser under the main icons script and global script F E DADATAMAWA COMSEM_Socket MEMResea 2D Global Script 93 im testmyForm stf Bet olo 2 Bal zlee Program testiyFort Var mi miz tmenultern tform h ithutton tm CMa inne nu procedure wyMenullick sender itobject hegin
98. de Material Infinite C Perfect Magnetic Conductor top PMC Perfect Magneti s Special Materials t _ Symmetry Wizard A Batch Scheduler Ak Differential ports g f WZ Layeri SS y Layer WN Layer 2 wit Fut Masts Files x 0 125 mm z 0 mm 2 5D Mode lt m aoe measann 8 TA C a Fig 43 Dielectric stack Select check boxes Material infinite Waveguide for both top and lower walls This way you specify that top and bottom covers are removed and that the lateral walls are infinitely long in the y direction By moving the mouse over the dielectrics window information about the composition of layers is displayed By clicking over a section you can edit layer parameters Alternatively you can click in one of the items in the list beside Later you ll also have access to any active layer directly from the Editor s popup menu Every shape that will be entered later will have the thickness of its embedding layer Layer 1 is by default very thin and in this case we will leave it very thin as layer 1 contains the switch bridge whose thickness is not very important in the current structure In the 3D mode owing to the need of correctly accounting for the y directed current gradients if objects in a layer are connected to objects in different layers sometimes it is necessary to require a slicing of the current layer the number of slices is indicated by Ny as described in the manual this raises q
99. depending on the frequency range and on the overall topology such a capacitance may play a significant role L C Let us consider as example a simple rectangular via conductor via Conductor a Ground Ny The junction between the two conductors acts as an unphysical capacitance C given by C ol w Ny k t k being an empirical factor of order of magnitude about 10 Ny the number of vertical subsections of the upper conductor If the DUT is the via behaving as a few nH inductor while the feeding line is some microns thick the resulting capacitance may well lead to a resonance in the lower microwave range It appears that the capacitance is related to the thickness of the single slice a thinner slice means a higher capacitance Such capacitance may be made arbitrarily large by raising the number of y subsections Ny or by reducing the conductor thickness or by raising the dielectric permittivity of the embedding material Ny is selected with the substrate parameters as number of y subsect Actually in version 5 2 a powerful device has been added namely the possibility of using non uniform slicing the first and the last slices may be selected to be much thinner than the remaining ones allowing to circumvent the capacitance issue by just Ny 3 while keeping the actual conductor thickness see previous section However this device forces currents to flow in a way similar to the currents you would have if you
100. disabling Add Edge Mesh x and Add Edge Mesh z options of the via conductor no mesh lines are displayed in the via and the program issues an Invalid mesh warning In fact in this condition no current in the x direction neither in the z direction is defined However if the via is small the only vertical y current is sufficient in order to correctly simulate the structure reducing both the number of needed modes and the number of unknowns dimension of the system The computational load is reduced for two reasons On the one hand there is a reduction of the number of current elements to be calculated size of the system and on the other hand mesh lines may be more spaced so requiring a smaller number of box modes when building the needed Green s function MoM matrix If you are voluntarily suppressing some current components to reduce the computational load you can avoid that the warning window appears during editing by selecting Action Disable Mesh Warnings Be careful if the warning is issued after importing some DXF or GDS file positioning entities in wrong layers may produce completely overlapping object that the mesh algorithm is unable to handle According to figure 23 it can be understood that when two shapes are in contact adjacent along x in this example Jx should not vanish at the extremes where the two shapes are in contact In fact vanishing of Jx would brake the current continuity and as result no or limi
101. e Circuits Tools Speci Ext Data Fil Fig 47 The bridge Now select layer 2 The bridge structure appears yellow if you require to show all layers CTRL A In layer 2 you should enter two more rectangles size and positions have to be the same of the first and last rectangles entered in layer 1 So we can avoid to repeat the same steps by right clicking and selecting from the popup menu Translate Move Copy All objects in layer Translate Move Copy objects in layer Paramet W Make a Copy 20 G From layer To layer ak J e Apply Cancel Help A 3D Grar n Mi Editor a i ji Circuite al fools Fig 48 Copying all objects in a layer 4 Require to make a copy of objects from layer 1 to layer 2 Then press ok This way the position of the rectangles is exactly the same Otherwise you d meet problems with the mesh as any item in one layer produces some mesh in items over other layers and minimum displacement may produce very close mesh cells so as to involve large computer resources Now delete the center electrode select it by mouse and press Del on the keyboard Incidentally note that since EM3DS 8 you can select multiple objects by keeping pressed SHIFT key and clicking over the objects or by enabling Select Group from menu Edit or from the popup menu If using the Select Group option you can click by mouse to set the upper left corner of a rectangle and then click to set the lowe
102. e along which the control voltage is calculated It is a plane parallel to the gate electrode Usually the control region is the depletion region beneath the gate electrode Message Dialog Be careful the control layer should not be the same containing the channel The control plane is the plane along which the control voltage is calculated Usually the control region is the depletion region beneath the gate electrode it cannot be the channel itself Message Dialog A controlled source cannot be applied to an ideal conductor please modify the resistivity value Channel cannot have infinite conductivity Message Dialog A controlled source cannot be inserted into a layer having non uniform slicing In this version you cannot define an active region in a layer having non uniform slicing selected Message Dialog Warning the inserted dielectric brick will share the magnetic permeability gt 1 of its embedding layer This is just a reminder the relative magnetic permeability of any object defined in a layer is the same of the embedding layer Event Remark de embedded results could lose accuracy over and near XX GHz the enclosure of the structure is a waveguide having a different number of over cut off modes with respect to the calibration structure for the Left ports Hint if this is the case you could try by displacing 118 the de embedding plane or add to your structure top and bottom metal covers Calibration requires that a set
103. e from the reference plane zero not allowed used in creating the standard Alternatively you can use any kind of termination in this case you can select load from file load to load the touchstone file describing the load used in the calibration Note however that the termination load must be diagonal This is especially useful if the process is used to evaluate multi port circuit calibration or in lab for multi mode calibration from experimental data Now load the standard and click once more the button create calibration file In this case the order of the modes is the one of the cut off Actually in order to sort the ports the algorithms use the evaluation of eigenvalues of a matrix if eigenvalues are too close the procedure can fail One can look at the eigenvalue and also at the error in obtaining the network if the check box Save Data About Expected and Calculated Eigenvalues is checked In this case a file Eigenvalues txt is created Error can be due to a number of reasons most notably if there are insufficient ports namely the structure has more accessible ports in the modal side than physical ports or if there are too many ports i e you are including waveguide modes far in the cut off region so that their contribution is nearly zero In both cases the results are in terms of error boxes namely the negate the circuit if do not invert sign in results is selected the actual network is exported XXV Abou
104. e mesh have been changed hence it is often useful avoid the automatic mesh update when changing the upper frequency of analysis this way no additional time for the first frequency re computation is needed Simulation may be stopped at any time the best moment to stop is when a frequency point is completed with its calibration All partial data are available and if calibration and analysis points match the analysis may be resumed without loss of information If you use SmartFIT at the end you will have two data sources the actual spot frequency calculation and the interpolated data set usually an additional trace whose name contains symbol in this particular case standard settings of SmartFIT do not show the impressive performances of this tool in terms of time reduction Usually SmartFIT performs much better if inside your band the response has pole and or zero such as in filters The Lowpass ems example clearly shows this You can display the response while being calculated by selecting from the Post Processing panel the Network Parameters button and by selecting Refresh during Data Processing from the popup menu 7 The best way to use the post processing features is to use the Data Browser Menu View Data Browser namely a tree where charts and data are displayed By right clicking over the data browser you can add Smith Charts rectangular plots current plots etc as well as to use post pr
105. e need of the user insight is mainly due to one of the main features of EM3DS the designer has no grid constraining placement of objects Hence when the user becomes familiar with this sort of tricks he may take strong advantage of the complete freedom that EM3DS offers Yi WU y Y Shadow mesh WILL UM Yj yaaa rr ZZ Fig 26 One Shadow mesh line in the middle conductor due to the conductor on the left hand side is very close to the one due to the conductor on the right Most probably displacing vertically one of the two conductors up to merge the shadow mesh lines will not affect the accuracy while substantially reducing the number of required modes in the z direction Remind that this number is directly proportional to the ratio between the enclosure dimension along z and the distance between the closer horizontal mesh lines MN RRS Shadow atesn line 2 y a M esh cells do M esh cells do align l NOT align ZZ ZZ G27 A a A ZZ T A J pG AA ZZ Z b Yj LZ LZ p NI AW U A ZA Z N AAAA a 4 Fig 27 When possible setting a should be preferred To this aim shapes adjacent along z as in this case should have the same Edge Mesh Distance x parameter Dual for adjacency along x
106. e of a conductor in dielectric brick and vice versa If the cache Asymptotic Info check box is selected and Save EM Computation is selected data about the Asymptotic approximation are saved in a mp file when discarding the current structure and are available for future use note that mp files are usually large and saving or opening them may require a while A red light in the Involved modes panel means that no Asymptotic Information is available hence a full simulation is required at the first frequency point A green light indicates that asymptotic information is available while a yellow light means that a file containing asymptotic information has been found and is currently being loaded so that you have to wait until it becomes green Actually there is a minor price to pay using the Asymptotic Approximation requires more memory Moreover a feature of EM3DS is that currents are modeled by piece wise sinusoidal PWS functions with frequency dependent argument as a consequence physically sound results may be obtained even with very coarse mesh Whenever the Asymptotic Approximation is used the argument of these functions 1s fixed at the lower frequency of analysis so losing this attractive feature XXI Even faster SmartFIT SmartFIT is an adaptive scheme for evaluating the response within a given band EM3DS will select automatically points within the range you have specified and at the end it will create an additional data set
107. e position of conductors with edge ports attached as effect of the optimization process some port is no longer defined the conductor no longer touches the box and consequently the optimization is aborted Message Dialog no variable to optimize please indicate by Y which variable in the above list should be used in the optimization you can define variables in the variable sheet and use them for the parametric definition of geometries Optimizer needs a parametric geometry to be defined Message Dialog Attempt to connect to remote license server failed message You are using EM3DS license in floating mode and EM3DS was not able to connect to the license manager in the host computer Message Dialog Server cannot enable remote license the max number of allowed license may have been exceeded You are using EM3DS license in floating mode EM3DS connected to the license manager but did not get permission to run this may be either because the number of available licenses is zero or because the license manager was settled to filer out requests from your PC namely from you TCP IP Message Dialog License for a previous version of EM3DS xx In order to run x x version you need to remove the existing license and request an updated license code Note that the new code will keep enabled the previous version of EM3DS Do you want to remove the existing license now EM3DS 8 and more will require a new license the new license will work for previ
108. e that this post processing may be applied to any data set even imported data However while the adaptive fitting will look runtime for significant frequency points the interpolation made in post processing phase eventually on external data is completely blind and interpolation may well be not satisfactory regardless of the number of input points The interpolation is in fact a standard rational interpolation As to SmartFIT note that even setting a relative error as high as 1 EM3DS will locate pole and zeros and may provide a good result with very few points if relative error is kept high results are usually poor if no pole zeros are in the selected band The checkbox Fast Interpolation will reduce to the minimum the controls and this results into a drastically reduced robustness this usually only works well for symmetric structure having in band pole zeros but not private poles Checkbox Do Not Use SVD may be used if for some reason interpolation fails SmartFIT will usually select automatically an internal solver for best performances Do Not Use SVD forces SmartFIT to avoid SVD solution SVD in the way it is used is very robust even though sacrificing some precision at the interpolation points This also affects the way in which the Broadband Spice Model Extractor works XXII Automatic De Embed Ports introduce a discontinuity partly due to the presence of the lateral walls In many cases this discontinuity does exist i
109. e views may be added and handled by he Data Browser or the main menu View XXXVIII Post Processing Far Field 3D View From the Data Browser you can select Add Far Fiel View A window similar to the one described in the previous section is created The far field is calculated and displayed by using a powerful rendering and 3D like perspective you should read the section about Antenna modeling to know about assumptions and limitations Far Field is only calculated if a Sense Layer was added to the project menu Action Add Sense Layer or button Add Sense Layer Radiated field is plotted in spherical coordinates In the setup panel the user can select the excitation port Stimulus port the amplitude of the excitation Stimulus Voltage Frequency and distance meters By default the distance is settled to zero meaning that the r dependent factor in the far field equation is replaced by 1 One can also select multiple excitations specifying voltage amplitude and phase at each port by checking Excite Multiple Ports this is needed to see diagrams for arrays of antennas Right click over the plot to handle it a popup menu allows selecting the plot mode 87 Far Field E Field Rendering 1 Rotate Zoom by Mouse Zoom In Ctrl N Zoom Out Ctrl O Auto Rotate Ctrl R Auto view Copy view Ctrl C Background Color Save View to File Displayed quantity Field Component v Show Grid v Show Axes Show Scale dB Setup Stimulus port
110. ecify the number of layers and the materials composing your switch Select the panel tool General and then click over the button Analysis and Substrate Settings alternatively click over the main menu Settings and then Analysis and Substrate Settings The Substrate Information window appears 36 EM3DS Electromagnetic 3D Solver lt Editor Sele 3D View Rendering 1 General Draw Edit tools Post Processing Substrate information and general options PER peoepocccceeeeeeseesosoooceseceseseeog ns Enclosure dielectrics Start Frequency GHz cr Step 1 GHz Stop Frequency GHz eo Num Points 2 CY Invoke automatically SmartFIT Num modes x direct he o Suggestion Num modes z direct ie no suggestion no suggestion Default Output Touchstone File no extension is indicated a rotate V Always use suggested values ita Browser Suppress wideband Mesh V Save EM computation ae Ine limit num modes V Automatic Deembed gt V Asymptotic approximation Help F1 T TATER MV 2 5D simulation 2D Graphs TP 6 3D Graphs Editor 3D Views ay Circuits Ag Tools Special Materials Mis gi Ext Data Files Involved modes x direction 5 3 co minimum suggest z direction 5 3 Discard Asyr c l Cache Asym Info 2 5D Mode W Marco Unian Outloo Microsoft Word Elec fw Revisioni Fig 42 Substrate
111. ecting the calibration procedure As a rule of thumb the de embedding plane should be placed at least at one substrate thickness from the enclosure at least for microstrips A remainder of violation of such a rule is displayed by the EM3DS when needed It is generally better to leave the reference plane coincident with the ports than putting it at a very small distance from the port Moreover the user should verify that at least one mesh cell is defined between the port and the calibration plane otherwise a warning is issued Plane reference distance for Left Ports o DeEmbedding distance um Cancel E Help Box size for Calibration Standard Same enclosure as Device Under Test C Automatic selection C User defined size lw Correct calibration near resonance Fig 62 Dialog for reference plane and de embedding options Since version 6 3 EM3DS allowed to select reference plane coincident with the port plane Actually whenever the users select a non zero reference plane both results namely at the specified reference plane and the port plane are available In order to be able to perform this further calculation EM3DS only to recover response at the port plane need some hypothesis about the nature of the discontinuity added by the port s and then evaluate its admittance This evaluation may fail if the enclosure is multiple of the wavelength actually failure occurs slightly before this condition over a band In ord
112. eed to re calculate so the best thing to do is usually to try XXIX Optimizer Once geometry is defined by means of Variables the optimizer can be invoked Select which variable to optimize by inserting Y in the corresponding position of the variable list as well as lower and upper bound pay attention that no geometry is be able to exit the box If you select also Tune The variable will appear in the tuner as tunable 67 Optimizer Upper Bound Tune MM 400 530 H Goal Editor Goal type Quantity Current EM Simulation 0 CE MAG 5 01 17 ga To Port 1 i a eas Goa From Fort 1 Mag Meas lt Goal Met Parameters Ss C Meas Goal Data Source Current EM Simulation 7 Goal Add Goal DB e o Aisa Cal e Enee dded 1 0 an Frequency points f Angle Deg 2 1 22 22 Run Optimization Cost History Pun Optimization Simplex Optimizer 10 10 al Max num of iterations 8 oO Tolerance a Help Close Show only Cost Histon during Optimization oO 23 46 69 52 E Revert to initial values Fig 75 Optimization Panel In the Goal Editor select the goals Select the parameter to be optimized insert a list of frequency points where the parameter is optimized then select Add Goal to have the goal in the Goal List Goals are relatively weighted according to what specified in the weight factor By selecting a goal you can see the details in the status bar and possibly del
113. eguide mode to the free space characteristic impedance roughly 377 Ohms This is only an approximation that may be helpful to model open environment but that should be handled with some care owing to the approximation involved that could lead to unphysical results The top and or bottom cover could be thought in this case as absorbing boundaries that should be kept far enough from the circuit in order to avoid direct interaction by near field usually half a wavelength is ok even if also lower values may provide satisfactory results To Probe Further 2 Modeling sharp vertical discontinuities e g vias When placing overlapping conductors on two adjacent layers e g vias in microstrip circuit in the 3D mode some care has to be used Connection across different layers causes a sharp vertical discontinuity While this is not a problem for infinitely thin conductors 2 5D in the 3D simulation this has to be correctly accounted for see figures below 13 As said above in EM3DS conductors are subdivided into vertical slices the first one being closest to the bottom of the dielectric the current distribution along the vertical direction is approximated by piece wise constant functions A sharp vertical in the thickness direction y discontinuity would require a large number of vertical subsections Generally speaking the incorrectly accounting for the discontinuity leads to a large parasitic serie capacitor in the network representation
114. ention on your mapping of layers If you have incorrectly selected such a mapping shapes belonging to different layers may be placed in the same layer and hence completely overlap In this case your warning is actually a source of computational error To Probe Further what mesh cells are used for As said before rectangular mesh cells are used as support for specific expansion functions the unknown current distributions are approximated by means of a set of known functions expansion functions defined over rectangular domains support According to the reference system appearing in the 3D view window the x oriented current component Jx is described by means of piece wise sinusoidal PWS function with respect to x and piece wise constant PWC function with respect to y and z Dually the z oriented current component Jz is described by means of piece wise sinusoidal PWS function with respect to z and piece wise constant PWC function with respect to y and x Vertical y currents are piecewise constant with respect to any direction they are a sort of cubes Vertical mesh lines Jx x SSS RNR Rams E Ty x Fig 23 Jx and Jy as function of x relationship with mesh cells Figure 23 shows as an example the behavior of Jx and Jy in the x direction Jz x is similar to Jy x the total current for Jx is obtained by superposition of the single PWS x A dual rule apply to Jz and its dependence from the z co ordinate 26
115. er to circumvent this limitation EM3DS from ver 7 0 5 adds in the post processing phase a correction algorithm that is enabled if in the dialog for reference plane see figure the checkbox Correct calibration near resonance is selected default If correct calibration near resonance is selected EM3DS will use 56 data from a lower frequency of analysis to correct resonance problems We want to stress that this is usually not a problem when reference plane distance is non zero as in that case no hypothesis about the nature of the discontinuity is made From a general point of view we can summarise saying than When the user selects a non zero reference plane the standard is in a box having double size with respect to the reference plane Hence in this case the user can control the size of the box by acting on the reference plane This may useful as in some conditions as discussed above the analysis of the standard may fail When the user selects a zero reference plane namely only the port discontinuities are removed the size of the standard is selected according to the user s selection 1 Same Enclosure as DUT Default 2 Automatic Selection the size is selected according to the upper frequency of analysis trying to keep the box size below A at multiple of the wavelength resonant conditions deteriorate the accuracy by which the port discontinuity is evaluated The user can try this option if there is evidence of such a
116. ete it If you have to modify a goal create a new goal and delete the old one The quantity minimized is the Cost function cost is defined according to N M 2 Cost gt Y w G fe M p Se n lk 1 where n is the number of goals w is the weight of the n th goal G is the goal and M the measured quantity There are several optimizers available and cost function is shown runtime The checkbox Show only Cost history during optimization allows to reduce the size of the dialog window during optimization Optimization may be interrupted at any time either by clicking over the stop processing button or the abort appearing in the progress window referring to the single EM simulation Button Revert to Initial Values brings back the variables to their value before optimization Remember that a good optimization can only start from a good design avoid to think this is a panacea Most typically optimization does not bring results if you have defined a set of goals in contrast each other or simply physically meaningless or just because your initial design was too poor A number of outstanding papers about optimization is available in the literature among them several paper by Prof Antonio Morini University of Ancona have focussed on the filter optimization showing that a filter can be optimized by only optimizing its response at a number of critical points By the same token one usually only needs some hot spots to be
117. fatal error will stop calculation The user should remind that if information about the Asymptotic behavior see p 8 is available from a previous simulation it is not discarded when changing the parameters of this window so that simulations by varying resistivity or permittivity of the brick can be performed very quickly Note that any constitutive parameter may involve frequency dependent expressions as well as parametric expressions 47 Material Specifications i O sort F e129 Resistivity Ohm m Dielectric Parameters 3 E per 0 tand Mw is a dielectric Add controlled source Scale Resistivity Assign Color _ ae hin active layer tin other layers Ok Cancel All cond diel Help Fig 55 Resistivity Material Specifications dialog box defining a dielectric brick Material Specifications 3e7 Resistivity Ohm m i a dielectric Add controlled source i Scale Resistivity Scale to thickness 0 001 Assign Color in active layer in other layers Ok Cancel All cond diel Help Fig 56 Resistivity Material Specifications dialog box Setting Scale Resistivity for a thin conductor Use dielectric bricks even in order to remove some dielectric area in the substrate e g by specifying a unitary relative permittivity or to model integrated capacitances Notes Avoid using 48 dielectric brick to remove conductive substrates The magnetic permeab
118. for a set of additional assumptions the circuit is electrically small electrical lumped analysis parallel plate capacitance formula is used to evaluate the clamped inter electrode capacitance The electrode surface has only to be specified for this kind of analysis it is not used in the em analysis In order to perform the lumped elements analysis only select the frequency range and then 107 press Analyze the results of this circuit analysis are automatically exported to external touchstone file added to the Ext Data File folder in the Data Browser and available in any 2D Chart They may be used directly into the circuit solver Figures below are a good example of the performances of this modelling They show comparison between experimental and EM3DS results for a ZnO FBAR 1 7 Frequency GHz Fig 112 Experimental validation of the full wave technique inEM3DS for a ZnO pure mode FBAR XLIX Creating queues of simulations the Batch Planner Batch Planner is a form used to create a queue of multiple simulations optimizations It can be accessed in a number of ways such as the Tools main menu or the icon in the Data Browser or the button in the toolbar 108 See ome Batch Planner f mA View mode rotate i Draw Ases Keep Ratio Show WR Walls W Real Time Ref L Zy Data Browser Esi Mow Editing layer 1 air Run Optimization oP Parameters Summar of events during batch sirulationoptimi
119. g Custom Measurements F oe This form is accessible either by the main menu gt Tools gt Measurement Editor or the button sa Frequency Domain Measurement Editor Custom Measurements New Measurement Custom Measurement 1 Ae51_ 1 1m51_1 Custom Measurement 1 ldentifier Custom Measurement 1 AeS1_1 lm51_2 ReS1_14m51_1 Expression Add to List Help Delete Custom Measurement OF Clear all list Fig 87 Custom Measurement Editor The Measurement Editor allows to create your custom measurements any new measurement will be available in all Charts Create a unique Identifier and enter the Expression defining the new measurement The Expression has to be created using the reserved symbols ReSfromport_toport and ImSfromport_toport for example ReS1_1 indicated the real part of S11 The expression can make use of any of the built in functions When clicking OK the list of measurements is updated and any chart will have available the new measurement The list of custom measurements is stored in a text file named CustomMeas prf automatically loaded by EM3DS at the startup In order to remove a measurement select it by mouse and click Delete Multiple selection is possible by keeping pressed the SHIFT on the keyboard Note The expression correctness is only checked when it is used namely when evaluating the measurement If for example you make reference to two ports and you apply the measurement to a data source involving o
120. ght clicking an additional popup menu is made available Quite often an Event window is displayed It is where EM3DS places notes remarks warnings and hints so as to help you properly set up the structure to be simulated by its popup menu you can clean that window so as to avoid to have old messages displayed You can find more about these messages by searching in the main help topic In addition there is an appendix at the end of this manual describing the most important and frequent messages A very useful newly added feature as of ver 6 is the following in all instances where the user is requested to enter a numerical value a valid expression is allowed that is numerically evaluated by the solver to yield the correct input data One may specify dimensions or material parameters directly through expressions e g if the available data is the resistivity of a conductor say 3e 8 yet the conductivity is required simply enter 1 3e 8 in the conductivity edit box Material parameters permittivity conductivity etc may also be frequency dependent and or parametric frequency is accessed by the global parameter F or f f is a reference to the frequency in Hertz Hence if for example you want to describe a resistivity that increases as the square root of the frequency and the first frequency of analysis is 1 GHz you can simply assign as resistivity ro sqrt f le9 Built in functions and syntax are discussed in the Appendix Since version 7
121. ging the resistivity of conductors or the dielectric permittivity of dielectric bricks NOT of the substrate Note the suggested value for the minimum number of Involved modes is usually very reliable However if a conducting path e g a microstrip is made over a strongly lossy layer e g semiconductor substrate the indicated value may be rather underestimated The underestimation may also occur if parameters of the dielectric stack are frequency dependent If the cache Asymptotic Info check box is selected and Save EM Computation is selected data about the Asymptotic approximation will be saved in a mp file and will be available for future use EM3DS always looks for that files and if files exist it tries to load them note that mp files are usually very large and saving or opening them may require a while A red light in the Involved modes panel means that no Asymptotic Information is available hence a full computation is required at the first frequency point A green light indicates that asymptotic information is available while a yellow light means that a file containing asymptotic information has been found and it is currently being loaded Actually nothing comes for free using the Asymptotic Approximation requires more memory Moreover a feature of EM3DS is that currents are modeled by piece wise sinusoidal PWS functions with frequency dependent argument this results in physically sound results even with very coarse mesh
122. gn At the moment it is limited to a single parameter but more work is in progress Additionally the multi mode calibration algorithm has been enhanced to allow its application in several measurement problems EM3DS 10 was developed to reduce the time needed to learn how use it with many on line animated tutorial Version 11 end 2010 introduces the Time Domain Reflectometry a set of time domain functions including the possibility to analyze the time domain to an arbitrary response and to see the time domain evolution of current field distributions Version 11 also adds the possibility to define your Own measurements custom measurement definition Version 12 fall 2011 enhances the parametric capabilities of EM3DS allowing to parametrize also the thickness of each substrate to define a list of sets of parameters and to automatically perform simulations and comparisons for each set of parameters Moreover several minor improvements are made available additional animated tutorials printing and print preview utilities etc Since ver 6 0 EM3DS was the first tool allowing the full wave modeling of FETs in linear regime this is accomplished through the insertion of distributed controlled current sources EM3DS 6 0 provides for the materials constitutive parameters to be frequency dependent and may further be specified by the user through analytical expressions formulas Every parameter in EM3DS can conveniently be input as a valid algebraic e
123. graphic file BMP or EMF in file The em simulation may be exported to file as touchstone depending by the current setting In ver 6 1 3 it has been added the ability to import BMP and JPG files to be used as background of your graph Add Bitmap as Background This is especially useful to compare calculated results with data in the literature by means of some scanning of available graphs and setting appropriately the options and limits of the graphics in EM3DS In rectangular plots displayed Parameters are S Scattering Matrix Z Impedance Matrix Y Admittance Matrix Quality Factor Q defined according to Im Yi1 Re Y1i where i is the selected port Group Delay it is defined as d 0 ow where j is the phase of S parameter The quantity is expressed in time units nsec Note that the derivative is actually an incremental ratio and data have to be available at least at two frequency points Phase Difference useful function to evaluate the phase balance of hybrids phase difference is in DEG and represents the phase difference between S parameters according to the selected ports N 2 Losses for a selected port p in an N port it evaluates gt If a device is lossless such a k l value is 1 namely O dB For a lossy device its value in dB represents the fraction of power dissipated by the device due to several loss factors dielectric losses conductor losses and possibly radiation losses when fed from port p
124. h as the name of the graphs may be edited in order to assign them a new name to this aim just click over the caption you want to modify By right clicking a popup menu allows adding more network plots Smith Charts Polar Antenna Plots current plots field plot near and far script macros written in Delphi Pascal multimedia document and external data External data are touchstone ascii files see to Probe Further and can be edited by the user Link to external data may be deleted by selecting the folder of the data and by accessing to the popup menu 70 Ti Data Browser Es Now Editing layer 4 F Parameters Ail Optimizer Tuner Add 3D view Rendering eD Graphs Add Data Source H 4dd Rectangular Network Graph Dene Graph 1 Ee Add Smith Chart ES Smith Chart 1 Add Antenna Polar Plot Add Current Field 3D Graph T Polar Plot 2 Add Current Field 3D Graph Rendering _ Add Contour 30 Graph FR 4dd Mag Force 30 Graph ia Current Density E Field 1 Add Far Field view 30 Graph rendering FATE Add Circuit ar Far Field E Field A enderin Add Circuit From File an i 3D Graphs dd Broadband Spice model extractor P Contour Plot Body F Pal Eontour Flat Bory Pore Add Acoustic Material Definition og Curent Density E Field Ri Ad script 4dd Script From File l fe i ditor 3D Views Add Global Script u Export EM Results to Touchstone File Add a Multimedia Player Help Difere
125. he layer being edited Ports can be selected by mouse edited deleted etc Charts can be zoomed panned etc e Enhanced mesh new options allow greater flexibility to control mesh in particular for non Manhattan objects e License server as service now license manager can either work as a program or as a standard Windows service running in background e Parameters layers may have parametric materials even when no frequency dependence is required e Measurements the fraction of power lost in a component for conductive or radiation losses is now evaluated III How to read this manual This reference manual is divided in paragraphs The sequence of paragraphs is selected according to steps and problems that have to be addressed in order to correctly setting up a typical electromagnetic em model of your structure At the end of each paragraph a set of FAQ Frequently Asked Questions discuss possible questions that are likely to arise in the reader Some sub paragraphs discuss more deeply technical questions To Probe Further and can be neglected in a first reading Bold characters are generally used to indicate menu items or buttons IV Licensing When EM3DS runs for the first time it generates an installation code that you have to send to MEM Research in order to have an enabling user code In order to directly generate an e mail containing the code just click where indicated The installation code is hardware sensitive so that any
126. he list of allowed clients otherwise the license server will refuse the license and the event registered in the Log panel Then you have to start the server be sure that you allows the software to access the network if for example you a have firewall License Manager will use port 8090 If License Manager is running in the server and you try to run EM3DS on the server itself EM3DS will get license from the license manager and you have to indicate as Local Host or IP 127 0 0 1 the server Otherwise if you don t need floating license simply do not start the License Manager and EM3DS will directly use the available license s To move the license into a new computer remove the license in the old one and send both the code generated in the old computer and the one in the new this way MEM Research will be able to generate the code to move you license License Manager is a standard program that needs to run in the server computer Alternatively EM3DS let you install License Manager as Windows Service In order to do that just click on the button Install License Manager Service When computer is re started the service is automatically launched and will work in background Only be sure that your firewall does not block its access to port 8090 The list of allowed clients is loaded by the service when it starts the list can only be created and handled by the License manager Do not keep License Manager running if a License Manager Service
127. he saturated and the linear values of the carrier mobility when available from Hall measurements 1 e a 52 where q is the unit charge n the carrier density and u the carrier mobility Note that when using 5 in MESFETs a slight correction may be needed in order to account for the layered model of the depletion region The controlled source across the low conductivity region of the channel or of the 2DEG completes the physical picture In EM3DS such a source is assumed to be J r G r r Er or E r 6 The operator G is the one linking the controlled source to the controlling field its domain is the Schottky contact being non vanishing just in the 2DEG or more generally in the channel An animated tutorial in the tutorials panel button simulation of an active device shows how practically set up the XX Asymptotic Estimator saving large amount of time with limited or no loss of accuracy Handling 3D structures could cost a rather large computation load However some devices in EM3DS allow reducing considerably the time needed for simulation In particular EM3DS implements a new algorithm resulting in a dramatic speed improvement The algorithm Asymptotic estimator requires a full and hence slow analysis at just one frequency point the first one some data related to the asymptotic behavior of the Green Function are mathematically manipulated stored and used to speed up the simulation over the whole band
128. here are frequency dependent mesh cells the higher is the frequency the higher is gradient of the current density in the conductors In order to account for that gradients EM3DS adds mesh lines according to the user defined upper frequency of analysis These cells are settled according to a worse case basis so that sometimes it may be useful to access and modify the size of these cells The dimension of the cells is entered by the Cell Size parameter x for vertical intervals and z for horizontal ones When drawing general polygons or circles this parameter is also tentatively settled by EM3DS so as to correctly discretize in a staircase approximation general shapes If the generated value is not satisfactory this sometimes happens with slanting lines a good idea is try to reduce this size see next paragraph The additional mesh option Uniform Mesh was added for polygons mesh cells become independent from the position and the number of vertices being simply uniformly added so as to fill the selected shape The size of the cells in this case is specified as fraction of the box size e g if cell x is 16 the size of the cell is a 16 a being the box width Using the Uniform Mesh options problems related with the number of vertices of a polygon are partially fixed Mesh line should be placed so as to avoid unnecessarily close mesh lines In fact a dense mesh implies a great number of unknowns in the final system see View Information about
129. hile computing network parameters X GHz lt solver message gt Unable to complete the system solution unable to perform the Cholesky decomposition Try by setting Gauss Solver as system solver Some error occurred while solving the final system as specified by the solver message Normally this should not happen If the problem is the hill conditioning of the final system you can try by switching to Gauss Solver one of the 2 solvers EM3DS avails menu Settings Preferences The implementation of the Gauss Solver is numerically more stable but requires much more memory and it is much slower Event Error while opening current distribution lt message gt When opening file including calculated data Dat network parameters are calculated from the stored 116 current distributions This error happen if EM3DS is not able to load DAT file The structure is displayed but results are lost An other possibility is that a DAT file does exist but is not calculated for the structure currently described by the EMS file e g you have manually placed a wrong DAT file with the right name or for some reason the structure in EMS was changed but results not updated To this aim EM3DS just performs a size check is the number of unknowns stored in the DAT file does not match the number obtained by meshing the EMS file the message is data not correctly linked to the EMS file This kind of error may produce a number of additional errors in computing network
130. icks defined in that layer The properties of the latter are accessed by selecting the object by mouse and by selecting Resistivity Material specifications from the popup menu If thick conductors are defined in that layer the dielectric layer properties specify the properties of the dielectric filling the volume beside the conductors 5 You have shorted your structure to the enclosure The enclosure acts as ground The only regions where a shape not intended to be a ground should touch the enclosing walls are where edge ports are attached In fact edge ports cut the conductor where they are defined Usually the above errors are easily identified by looking at the current density plot For example in case 4 you would see currents vanishing near the excitation port In case 2 you would see a cut where two shapes were supposed to be in contact FAQ 5 Sometimes I get an Invalid mesh warning and some shapes become red Why As a general rule if a shape has no vertical z mesh line it has no horizontal x current component defined and vice versa This is not necessarily source of error as in some cases you may want to neglect some current component due to the expected solution in order to reduce the computational effort see next To Probe Further section If this is the case you can disable warnings by selecting Action Disable Mesh Warnings from the main menu If you were importing some structure e g by a GDSII file you should pay att
131. ientific notation A group of up to four 0 characters can immediately follow the E E e or e to determine the minimum number of digits in the exponent The E and e formats cause a plus sign to be output for positive exponents and a minus sign to be output for negative exponents The E and e formats output a sign character only for negative exponents XX XX Characters enclosed in single or double quotes are output as is and do not affect formatting Separates sections for positive negative and zero numbers in the format string The locations of the leftmost 0 before the decimal point in the format string and the rightmost 0 after the decimal point in the format string determine the range of digits that are always present in the output string The number being formatted is always rounded to as many decimal places as there are digit placeholders O or to the right of the decimal point If the format string contains no decimal point the value being formatted is rounded to the nearest whole number If the number being formatted has more digits to the left of the decimal separator than there are digit placeholders to the left of the character in the format string the extra digits are output before the first digit placeholder The following table shows the effect of various format strings DisplayFormat Value Result Comment HH t22 12 2 Note extra digit to right of decimal still appears 00 2 5 2 5
132. ility is the same of the embedding substrate Dielectric bricks are used in the same way as conductors A controlled current source may be superimposed by selecting Add controlled source this is used to simulate active linear devices like MESFETs HEMTS etc The user has to select the direction of the controlled source x or z The source will be proportional to the voltage calculated across a given layer usually the one defining a Shottky contact and selected by the Control layer list The proportionality factor is the transconductance gm mS mm or S m The control voltage will be taken along the co ordinate of the control plane in the control layer The control plane is displayed as a cyan line Modeling active devices requires an in depth knowledge of the working principles of FETs for more information see next section Modeling Active Devices Notes and restrictions layer including controlled sources cannot have non uniform slicing Scaling resistivity not allowed The controlled source cannot flow across a dielectric brick Controlled source cannot flow across perfect conductors zero resistivity not allowed An object including a controlled source cannot touch other similar object Modifications of the parameters pertaining to the controlled source produce automatic discarding of the asymptotic information unlike what happens when modifying conductor properties or converting conductors in dielectric bricks Using controlled source
133. in order to negate circuit S1 port of S1 has to be connected to port n i 7 of NEG S1 in the simple case of a 2 ports either you have to connect port 2 of S1 to port 1 of NEG S1 or port 1 in S1 to port 2 in NEG S1 If S1 is a 4 ports port 3 has to be connected with port 2 of NEG S1 while port 4 to port 1 of NEG S1 NOTE INTERNAL PORTS EM3DS can also create results where one of the ports is off ground either using a via port attached at the bottom of a conductor which in turn is connected to an other conductor below see figure or using internal planar ports see section about ports Let us suppose that you want to connect a resistor at circuit level between points and local ground The correct connection is to attach one lead of the resistor to the port and the other to the common ground as shown below Off ground port Resistor Common ground Fig 97 How to connect to an off ground port Ports have to be connected to the circuit under test the syntax 1s 92 P lt n gt Where n is the node numbering of PORTS is automatically assigned according to the order of appearance in the net list Results are automatically saved as Touchstone file according to the name of the circuit The name of the circuit may be modified by a simple click in the corresponding element in the tree of the Data Browser Moreover Results are added in the External Data Files folder in the Data Browser window they are available as
134. internal port the limitation is that no more than one internal port per object can be added If more are needed split the object Press shift to select multiple objects or use the main menu Edit Select Group or from the popup menu or from the button to enable selection of multiple objects Multiple objects can be moved by keyboard arrows cut copied pasted edited for meshing and material properties By double clicking over an object the Dimension and Position dialog window is open Additionally once an object or a group is selected you can move the item s using keyboard arrows delete the item s using del key change the size of the item using Shift the arrow key only for single rectangular conductors right click with the mouse over a item to get additional popup menu double click to access all the object features position size mesh options material etc copy ctrl c or menu Edit copy or button or popup menu paste ctrl v or menu Edit Paste or button or popup menu cut ctrl x or menu Edit Cut or button or popup menu mirror x x or menu Action Mirror x or popup menu mirror z y or menu Action Mirror z or popup menu When an object is selected a popup menu allows changing position and dimensions of the selected conductor changing the mesh options changing the conductor resistivity selecting the position of de embedding planes checking what shapes are in contact with the selected one Y
135. ion to another the mesh algorithm may be changed in order to improve it and as results DAT are current distributions it is possible that the new mesh will be different from the previous one and results not usable Only dynamic results are lost hence of course if you have exported S parameters they are still there Message Dialog This file has been generated by a previous version of EM3DS while it can be opened without problems if you have to modify it or running a simulation please check the mesh options note that in the present version the Border mesh ratio refers to the box This message appears when opening files generated by very old versions of EM3DS the meaning of one parameter was changed in the newer versions so that editing the structure should be made also considering that the Border Mesh Ratio parameter may be wrongly settled Event WARNING the suggested value for the number of modes is high check the mesh options and the position of your conductors The number of suggested mode exceeds 500 either for x or z directions This happens as two adjacent mesh lines are too close and are highlighted by red color Displacing if possible the red lines is 115 recommended Event Warning the Asymptotic estimator may need more modes than presently selected The asymptotic estimator allows to reduce the number of modes needed for the computation with the only exception of the first frequency point the first time a st
136. is installed to avoid conflict between the two licensing schemes You can monitor start and stop the service from the Windows Setup panel Control Panel Administration Tools The Service does not provide direct feedback to the user information and messages about its activity can be retrieved via the Windows Events Viewer V EM3DS Design Environment In order to start EM3DS click on the Start button on your desktop and choose EM3DS 12 If EM3DS has not been configured by the installer you can start the application by double clicking over the file EM3DS 12 exe found in the folder where you have unpacked the program files The EM3DS main window appears as shown below 4 EM3DS Electromagnetic 3D Solver File Edit View Settings Action Tools Window Help 3 i Editor Belay 3D View General Draw Edit tools Post Processing Tutorials View mode rotate V Draw Axes Actual Aspect Ratio Show WR Walls V Real Time Refresh dh HE Tools Special Materials Misc gi Ext Data Files cript 2A Global Script all BF Animations Z Layer IN Layer 2 7 start MRA W Posta in arrivo Fig 3 EM3DS main window le Fis Microsoft Word doc B EM3DS 2008 A new system tray icon will appear in the Windows toolbar where the user can request to hide show EM3DS while running The workspace is the main window of the simulator There are 4 operational modes conveniently selected by buttons on the toolbar Genera
137. l Draw Edit Post Processing and Tutorial In General mode the user sets up the entire simulation defines the structure of the dielectric stack layers frequencies if adding a sense layer for antenna simulation project notes etc It is very important the users pay close attention to the appropriate set up in this mode to properly model the structure of interest In Draw Edit mode users draw the structure by placing conductors and dielectrics on various layers The default view is top down however the auxiliary 3D View window displays the complete overview of the structure and is real time updated The active layer is highlighted in red In addition to this 3D View EM3DS features a 3D Viewer with Rendering supporting OpenGL This is an indispensable tool for getting design details in structures of a big aspect ratio or where the density is growing up quickly This viewer is easily accessible by the dropdown menu View and selecting 3D view with Rendering or by the popup menu in the Data Browser If in the preferences panel menu Settings Preferences one selects the checkbox Create 3D View with Rendering by default one of those view will be available for a new project It should be noted that this feature is_ hardware dependent and may not work well by all graphic cards The editor also shows in the lower status bar coordinates of the cursor size of a shape being drawn suggestions and indication of the solver mode either 2 5D now defa
138. l was available and created over one of the tunable variables see Macromodel the results are updated in real time in response to the tuning without additional EM simulations XXXI Parametric Simulation You can access the parametric analysis form either by the main menu gt Tools gt Parametric Analysis or the button or the same icon under the Data Browser It allows to define a list of parametric setups and to run a set of simulations one for each parametric setup 69 4 parametric analysis Set 1 a 1 b c 3 Set 1 1 b 2 3 lt insert here your list of parametric assignements for example a Delete set Add a new set c 1e6 8 d 3 use a Enter for each new variable Cancel Ifa variable does not exist itis created Set lt here define a name tor the set of parameters Results to be saved Summary of events during parametric simulation sc O B W De Embedded Help Run Parametric Simulation Reference to Port Save each simulation as a complete project Fig 77 Parametric simulation panel Insert in the edit box insert here the name of the variable and its value e g a 1 Remember not to insert spaces and end the definition by the symbol Press Return or Enter to add additional variable definitions If a variable does not yet exist it 1s created with the assigned value Then select a unique name for such a set of variables and enter it in the proper editbox lt
139. le either 1 in the complete path stored when saving EMS file or 2 in the same directory of the EMS file hence you can quickly fix the problem NOTE While the Authors believe that the information and the codes are correct all parties must rely upon their own skill and judgement when making use of it The Authors do not assume any liability to anyone for any loss or damage caused by any error or omission whether such error or omission is the result of negligence or any other cause Any and all such liability is disclaimed 120 Summary Users Montal a cessnsrscistedeectieaapeanatveduoniesauendttiedaendiesannaeaeacesadsernneosebadeaseiensreapaunaesadoes tens l a E D e N ec eee ee eee l I What s new in Ver 11 12010 wisssisncusanscesacnonsbenesiunhieserioasdinanmsentivnsnigasionennsientionevinavbinanustedionss 2 H How oreades Maindalen inkin unenee EEA EEEE 4 DT a e E E E E EE EE EET 4 V EM3DS Design EnyiIronMelt nsscserriciri er inner co etaabivmnaadtinnccaniinmmdantisetwicananmectaliente 6 LACEE TATE a E N A 8 To Probe Further 1 setting top and bottom wall properties eee 13 To Probe Further 2 Modeling sharp vertical discontinuities e g vias 13 To Probe Further 3 Additional Options cccccccceececeeceeceeeeesesesseeeeeeeeeees 16 VII Perfect Magnetic Conductors PMCs and symmetry planes ss000000ee 19 VII Combining PMC and PEC or even odd simulations the Symmetry Wizard 2
140. librated results do not rely on any hypothesis and hence are reliable Note that the feeding line parameters may lose accuracy well before this message is displayed it is just sufficient that the whole line length in the calibration structure be near resonance this is common to any system exploiting circuit theory If the feeding line parameters were of primary interest for you try by reducing the distance of that planes from the ports Event Remark be careful layer XX includes lossy conductors while being non uniform y subsections checked this option works only in an approximate mode for lossy conductors 117 Conductors may be vertically sliced and the user may require that the first and the last slices be smaller than the others While such a condition allows to model correctly flowing of currents in ideal conductor in actual lossy conductors currents may distribute itself within the whole section and the non uniform slicing constraints the solver to a unphysical assumption Owing to an internal compensation algorithm results are reliable also in such a case only current visualization may be affected and this remark only reminds that the internal compensation algorithm will be used Message Dialog Missing nodes at line XX Circuit solver Syntax error in using the Circuit solver the parser was unable to find the nodes the component is connected to see p 54 Message Dialog Missing Component Value at line XX Circuit solve
141. load for standard 1 Magnetic Woe eee Load from file load for standard 2 Waveguide width a R p eT E Waveguide height Save data about expected and calculated eigenvalues Short Distance Short Distance 2 Do not invert sign in results 0 o Select a valid calibration File or standards in order to create a calibration File Procedure two standards this is the easiest but unpractical for measurement purposes you build a double symmetric or mirror standard and a standard involving the approx open enclosure termination on 377 Ohm As example consider a grid of strips involving 12 ports and exciting a waveguide the double or symmetrical standard is shown in figure and represents a mirror of the structure to be characterized 377 Ohm plane 61 Results from the two simulations are loaded by clicking over Thru Standard namely the double standard and Standard at 377 Ohm the one involving the absorbing boundary Waveguide width and height should be settled to the correct values and if the waveguide is filled with dielectrics namely the region defining the reference plane indicated with the distance d in the figures sets their values in the respective edit boxes At this point click on the button Create Calibration File The calibration file is a 24 port network whose ports 1 12 in our example are such that when connected to ports 1 12 of the structure remove the structure itself allowing t
142. m Ies eee aag A D DATA AWR COM EM_Socket MEMResearch Sou 5 4 Parameters 2D Graphs bata Graph 1 Dei Graph 2 a Smith Chart 1 3D Graphs A Current Density E Field 1 l Bp Editor 30 views HE Circuits I a Tools Special Materials Misc gi Ext Data Files al Script 2a Global Script Z Layer SX Layer 2 Z N Layer2 SN FEE x 1 125 cm z 0cm Edit Mode 2 5D Mode ps oe Skype m fim 3 Esplora Lo Bo pty t EM3D511 1 Microsoft Wo H manual10 pd HTML Help W 4 EM3DS Done 3 Immagine P T AI io 18 55 Mesh Preferences Let you specify the default mesh options to be used when placing polygons spirals etc Note the preferences are stored in file Shapeed9 prf You can remove this file if any issue is related to your settings in this case EM3DS will create a new file with standard settings 113 Appendix I Built in functions and syntax Any parameter in EM3DS may be entered by means of expressions The expressions may involve the following functions and operators they are not case sensitive Trigonometric functions Sin x Cos x Tan x Cotan x Arctan x Arg x Exponential Logaritmic functions Exp x Ln x Log1l0 x Log2 x General Sqrt x Sqr x Abs x Sign x PI Integer Trunc x Ceil x Floor x 114 Appendix II Solver Messages In the following is reported a subset of the possible messages issued by the EM3DS with
143. main ones being l there are so called Border or Edge Mesh Lines The main function of edge is to improve the ability to model near singular edge currents hence to ensure that sharp current gradients near edges are correctly modeled At low frequencies low when comparing wavelength and 22 structure size edge mesh lines may even be the only ones needed in order to mesh the structure The user has a nearly complete control over the position of the Border Mesh Lines The parameters Edge Mesh Distance see fig 22 indicate at which distance from the border as fractions of the box size edge Mesh Lines are placed For example a value of 16 for the Edge Mesh Distance x parameter says to EM3DS to place vertical lines near the border at the distance a 16 where a is the horizontal box or waveguide size Generally values range from to 100 150 Note that if these lines are close to other lines so probably unnecessary the current version will automatically suppress them this may be a drawback if you want that lines it is simply circumvented by raising the Edge Mesh Distance Edge Mesh Lines may also be suppressed by the user in this case deselecting Add Edge Mesh x vertical border lines namely lines identifying intervals over the x axis are not defined By deselecting Add Edge Mesh z horizontal border lines are not defined EM3DS usually sets the value of the edge Mesh distance according to the size of the user selected grid you can draw ei
144. mbedded results are available where error network parameters are available Message Dialog The user required waveguide calibration cannot be performed calibration data are not calculated at the same frequency points of the current e m simulation Waveguide calibration requires a calibration file calculated at the same frequency points as the available raw results Event Warning waveguide below cut off at f X Current theory for the waveguide calibration was developed under the hypothesis of just one mode over cut off being accessible Tests for general cases are in progress Message Dialog Unable to complete the network parameter calculation numerical error An unexpected numerical error has occurred probably floating point overflow Message Dialog The number of frequency points is not sufficient at least 2 values are needed 2 frequency points at least are required for Spice Model Extraction Event Warning de embedding plane larger than half wavelength check de embedding line parameters XX GHz When the error network parameters are known from the calibration procedure they can be used so as to calculate the feeding line parameters provided that some topology is hypothesized The feeding line parameters are calculated correctly only if one period of the feeding line is in the calibration structure Otherwise the displayed feeding line parameters are affected by a significant error up to become completely meaningless Note that ca
145. mensions Units Analysis and subs Settings General Draw Preferences of v Lop Mode Editor TTE piji 10 Fig 8 Selecting the working mode The 2 5D mode is currently the default mode as generally the 2 5D is enough while being simpler to use not to mention its efficiency While many solvers consider via conductors as special entities with respect to standard conductors EM3DS due to its 3D nature does not distinguish between the two Hence in order to make easier to convert a 3D structure into 2 5D counterpart the following assumption is made in 2 5D mode layers having odd index layer 1 3 5 etc are where planar conductors are placed they are considered infinitely thin and their inserted thickness is only used to assign a value for the calculation of conductor losses Planar conductors support only x and z directed currents surface currents An empty odd layer has absolutely no effect on the calculation regardless its thickness or composition Hence odd layers may also be used as dummy layers layers not having any specific application if not making possible to use the 2 5D convention by the same token in 2 5D mode layers having even index layer 2 4 6 etc are where vias are placed Vias have only vertical y currents so that they cannot be used to model e g a wall of a cavity or general 3D features If you need these features consider to switch to the standard 3D mode A substrate must have even layer
146. modifications made to the structure by EM3DS are not reported back to Microwave Office However work is in progress to make fully bidirectional the link to the object In order to access this feature the user has to run the registration utility REGEM3DS exe If the main EM3DS file EM3DS 12 exe is not in the same directory of the registration utility locate it Then click on the Register button If AWR Microwave Office 6 or following versions is registered in your system the process will successfully terminate At this point EM3DS should be available into your AWR Environment 109 Fat Fat oa r Registering Unregistering Utility for EM3IDS Simple utilty to register Unregister our EM3DS copy as COM Server for Client Applications Unregister Locate EMSDS mw Redgister Unregister for AWA Microwave Office 6 as client Fig 114 Registration Utility REGEM3DS Just create a new EM structure LJ bee Design Motes Project Options Global Definitions LD Data Files S Circuit Schematics Annotations z m Ea Materia Options Output Egu Graphs Optimizer tar Yield Goals t Output Files Collapse All H E wizards Expand all Mew EM Structure Link To EM Structure Import EM Structure Fig 115 AWR Microwave Office 6 adding an EM structure You will be requested of selecting 1f creating an EmSight or an EM3DS structure you can also set the simulator later Then you can proceed to draw your structure in
147. n Aim The Macro model builder is a tool to create a parametric simulation EM3DS runs a given number of simulations for a varying parameter and interpolates the response to predict the circuit response over a continuous range of the selected parameter Such a macro model is stored in the project actually an additional file having mmd extension is created and allows to see in real time the response of the circuit when the parameter is modified The macro model can be used also for optimization see Optimizer purposes Restrictions In the present version the macro model can be built for a single parameter optimization can only be performed over the macro model if one single variable is being optimized 66 In the present version there is no automatic criterion implemented to check the reliability of the macro model namely if the number of EM simulations was sufficient or not Always check the result of your optimization by a final full wave simulation of the response In the present version if a macromodel is created it is not automatically discarded when the structure is manually modified by the user but only when a new macromodel is created or if the file mmd is removed Pay attention to this fact as a modified structure can be linked to a meaningless macromodel Use Click Refresh List Of variables to have the list of variables updated and select from the Variable list box the parameter over which to build the macro m
148. n of Spice compatible equivalent circuits JEE Electronic Lett vol 41 No 22 October 2005 XL Post Processing Linear Circuit Simulator EM3DS provides also a simple linear circuit simulator From a given circuit topology including lumped e g resistors inductors etc distributed transmission lines external data em simulations elements it calculates network parameters In order to create a Circuit Solver Window right click on the Data Browser window and select add Circuit or do the same operation from the main menu Tools The circuit solver works on a net list namely a list of nodes the components are connected to including the component values or definition YP C Data ShapeE d144Prototipo Linee TR File Edit Componente Aun Help i MEM Reseach circuit solver ver 1 0 c 2002 use TL nl gt lt n2 gt lt L gt lt 4o0 gt sEeff gt where lt n gt are ne Sno units have to be specified in TL SITLL 1 20 0107 100 02 324 ITLC 2 3 0 0077383 20 0 2 Aa EEE ATLL 3 40 0179 100 0 2 34 i Aun Settings Start Frequency GHz Stop Frequency GHz E Paste Add Capacitor num pointa AITLC 450 0084418 20 02 Undo i ITLL 5 6 0 0184 100 0 2 3 Se L LITLE 6 7 0 0084418 20 0 2 Se ieee ATLL 7 8 0 0179 100 0 2 38 ae Step 1 GHz TLCS 90007363 2002 TLLS 100 0107 100 0 2 384 P P 1d successfully completed 17 17 14 result
149. n real structures so one has to include its effect This is e g the case if a coaxial connector is used Even when such a discontinuity is an undesired effect it may be neglected as well in many 54 important cases in filters resonators and antennas the resulting additional shunt capacitance ranging around 0 1pF produces a negligible effect at least one the moduli of S parameters This is not the case of small discontinuities as e g a microstrip bend or cross and generally of electrically short structures where the discontinuity effect may heavily affect the results and need to be removed Moreover often some additional line length introducing additional phase shift and possibly losses is added in order to keep the analyzed structure far away from the box walls the user may want to characterize the structure by removing the feeding line effect To this aim a de embedding calibration algorithm is implemented Note that in the present version only edge ports are de embedded The de embedding algorithm is a new Short Open Calibration SOC technique presented in JEEE MTT April 2001 in a paper by M Farina and T Rozzi usually de embedding requires the analysis of two standards with different enclosures to be computed while in this approach only one standard is used If more ports are coupled at the same side coupling is also removed by de embedding De embedding plane Fig 61 Device under test DUT including a feeding line an
150. nd size of the middle electrode expressions allow to automatically place in the middle of the box the conductor The structure is virtually ready to be simulated However ports have to be specified 5 Click over the Add edge port button then click over the center CPW conductor near the left side 42 TE EM3DS Electromagnetic 3D Solver File Edit View Settings Action Tools Window Help r T ZE FM3DS loaded D DATA AWR COM EM_Socket MEMResearch Source EM3DS 7 MEMSTutorial EMS Version 7 0 3 Beta DAR TE 3D View General Draw Edit tools Post Processing A Add Edge Port REEERE REEERE REEERE RRR View mode rotate M Draw Axes Actual Aspect Ratio F Show WR Walls V Real Time Refresh Data Browser Ee Now Editing layer 4 db Parameters db 2D Graphs oP 6 3D Graphs a R Editor 3D Views any Circuits Gia HE Tools Special Materials Misc gi Ext Data Files A Script 2A Global Script Animations Z Layer1 SX Layer2 Layer3 Layer 4 I Layer 5 H Layer 6 x 100 um z 0 um 3D Mode Fig 50 Edge Ports TE Events Messages lnahle ta find file NANA TASAWR COMSEM Sacket MFPMA A green box will indicate that the left port has been added Repeat the same steps to add one more port at the right side Port numbering is automatic and appears when moving the mouse over the port symbol This is enough to start the simulation However we have not yet specified the reference planes If no reference plane is
151. nductors In order to add them you click over I i the button s for x directed ports and he for z directed ports Either use the main menu Action Internal ports are the most difficult port to use and should be used with care as they are not ground referenced Basically if the user adds an Internal Horizontal Port to a conductor the conductor is cut vertically as shown in the figure and a voltage generator is applied across the resulting gap Conductor Conductor reference side excited side Infinitesimal gap Top View Fig 70 Internal Horizontal Port namely field along x Ports are actually impulsive impressed fields lying along one direction and not vanishing over an infinitesimal gap The current across the gap is continuous and the short circuit admittance is measured across the gap consequently one of the two parts of the conductor is ground reference for the other the latter being indicated by a sign Internal port can be reverted exchange sign and displaced by double clicking over the port 63 Poste Terminal Reo co f on the right ne u f oon the Lett Position distance trom Lett 0 024401 51 cm Cancel Fig 71 Port Dialog The position is with respect to the hosting conductor top left Refer to the section describing the circuit simulator to have more information on how correctly using results obtained with off ground ports As a restriction the
152. ne strip having the upper or the lower wall settled as Material Infinite waveguide all the waveguide modes are terminated on their characteristic impedance In EM3DS you should need only 2 layers Fig 67 Matched Standard In the above figure in layer 1 is drawn the microstrip the top wall is perfectly conducting while bottom wall is infinite waveguide In version 5 2 the matched standard may be replaced by a short standard if in the above figure the bottom wall is perfect conductor you have a short standard In this case calibration file requires to specify at which distance from the calibration plane the shorting plane is placed be sure that such a distance is consistent with the one used when defining the thru standard Analysis of the structure and of the standards does not require and it is not recommended that the standard port de embedding be enabled the port discontinuities are automatically removed in the following calibration procedure 59 l Waveguide Calibration Window Miel x Files Settings Help Items m M Calibration Waveguide width X 2285 mm b T Thru Standard a Matched Load Standard short Distance M Short Std C Data Shapel di diw G Test wacalshorty 1p 45 mr Beate Ealibratan File Short Std added as data source l Show WR Wall M Real Time Refresh Fig 68 Waveguide Calibration Tool Once results for the two standards are available you can process them t
153. nel Field at a given co ordinate in the xy or xz or yz plane is shown according to the selection in the Set up or control panel The control panel is only displayed if Display Setup panel in the popup menu is checked From the popup menu you can load formulae from file load text containing desired expression save formulae to file save text containing expression copy view as metafile copy into the clipboard as EMF note the legend is not copied copy view as bitmap copy into the clipboard as BMP note the legend is not copied copy Legend to the Clipoboard copy legend into the clipboard as BMP visible only if legend is visible save view to file save view to file note the legend is not saved save Legend to file save legend Display Set up panel show the control panel Background color change the background color default is black Animate Animate view either in phase or frequency according to the selection in the control panel Show Legend Display the legend of values legend can be dragged and dropped over the graph Show values Display current values in the status bar when moving mouse Values are not 86 calculated if more than one layer is displayed Show Magnetostatic Field Assign Panel Display the panel used to assign magnetostatic field Panel may be dragged and dropped by mouse over the graph In the control Panel When more than 1 expanding function is used along the y conductor thickness directi
154. nes or polygons POLYLINES according to the user selection NOTE DXF standard has been modified several times since its definition hence exporting or importing DXF files may not work properly over any external program or different versions of programs GDSII is surely a very robust standard and its use for exchanging data is recommended GDSII import filter is shown below If Discard Existing Objects is selected default importing a file results in creating a completely new project Otherwise it 1s possible to import several structures in the same file Auto map Layers allows that EM3DS automatically creates a number of layers adequate to include all layers being imported Each GDSII layer is imported into an EM3DS layer GDSII Translator Eg Layer List List of Structures to be imported Ignored Commands E ntittes 1 75 um_microstip pad flO OF d a Auto map Layer W Discard existing objects iw Metric Fig 104 GDS Export window GDS translator is very robust The only assumption in the present version is that whenever more structures are defined no cross reference between structures is used I all entities are grouped into just one structure no problem arises XLVI Using EM3DS with command line files that can be associated to EM3DS When clicking over a file that has been associated by Windows to an application the action that Windows performs is to pass the name of the file being clicked to the associated application
155. nly one port an exception is raised by the expression parser XXXIV Post Processing Time Domain in EM3DS Time Domain Reflectometry is a powerful technique allowing to determine the origin and the position of discontinuities in transmission lines as well as to study transients in a circuit Usually it relies on the anti Fourier Transform of the frequency data in order to obtain the time domain evolution of a signal and programs implement this procedure practically by using FFT algorithms This poses some restriction for example frequency points have to be equispaced When processing data which are not equispaced this imposes some kind of interpolation with all the precision issues related to this choice In EM3DS it is implemented a different point of view When looking at the frequency response of a system at a single frequency fo let s say S fo we are basically implying a term exp j t so that the actual time domain response is s t Re S fo exp j o t this is the response to the stimulus cos t If we have two frequencies f1 and f2 considering the linearity of the systems involved in our analysis we can evaluate by superposition of effects s t Re S f1 expg l t S f2 expg w2 t which will be the response to the stimulus cos 1t cos 2t There is no restriction on the position and the number of frequencies Hence continuing we get the general case s fi Re SISA et f as response to the stimulus 80 sft N
156. ntal x port or Action Add internal Vertical z port or Action Add via port and then click over the desired conductor Ports are unit voltage generators used in order to excite your structure and to measure currents Edge ports are excitations applied with respect to the lateral walls while via ports are vertical unit voltage generators applying an impulsive y directed excitation field Internal ports are voltage generators either along x or z directions applied across a z or x cut in a conductor Ports can be selected by mouse edited or deleted also you can use DEL key when a port is selected Select reference de embedding planes you can specify a de embedding plane for each side of the box even if this is not strictly necessary these planes are accessed by right clicking over the conductor by selecting specify de embedding planes from the popup menu if the conductor has at least one port or by double clicking over an edge port and by specifying the distance from the wall A de embedding algorithm removes discontinuities due to the excitations and the part of feeding lines up the defined plane indicated as a green thick line In order to perform de embedding one standard structure for each side is automatically built and analyzed Regardless the position of the reference plane EM3DS performs the calibration and provides additional results referenced to the port plane Run simulation just press the Go button You can st
157. ntial ports ai Ext Data Files Global Script E Animations Fig 78 Data Browser A plot is displayed by double clicking over the leave referring to it e g Graph1 in the picture above Data files are reported in additional text windows whenever the user double clicks over its folder Information about settings names and number of graphs is stored ina GOS file Ascii file By any 2D chart the user can plot compare and export network parameters Network parameters 71 can also be exported via the menu Tools Export Touchstone and in this case settings about which kind of matrix exporting if calibrated or not whether S Z or Y parameters are taken from the first rectangular chart in the list On the other end if you are exporting from a rectangular network chart the kind of exported matrix depends on the measurement being displayed e g if the active trace is S it exports S etc if de embedded is selected calibrated results are exported When moving mouse over the 2D chart the lower bar displays the value of the point where the mouse is Data referring to a structure being simulated Current EM Simulation as Data Source may be shown at the end of the calculation process or during processing if Refresh data during processing in the pop up menu is selected If de embedding is available the de embedded check box allows showing and exporting de embedded results Hence the user has always access to both raw and calibrated re
158. o have sound parameters the de embedding planes should not be placed at more than A 4 from the enclosure If this condition is not satisfied the line parameters could be incorrect as highlighted by a warning however de embedding works correctly as well as it does not rely on these parameters If the calibration structure resonate at some frequency point calibrated results appear to contain some narrow spikes and at the same frequency the feeding line parameters contain similar irregularity Usually spikes disappear by reducing the distance of the de embedding planes If the structure is enclosed in an infinite waveguide top and or bottom walls not present or terminated in absorbing boundaries some times the de embedding may be not accurate de embedding is performed by building up a structure having a length double with respect to the de embedding plane calibration structure The enclosure of the original structure and the one of the calibration structure may have different modes over cut off leaking power so that the calibrated results may be affected by significant error To solve this problem you can place the de embedding plane at right the middle of the box if possible or by adding top and bottom cover in order to avoid power leakage what of course cannot be done when analyzing antennas see last section One more problem can be caused if the calibration plane distance is too short in this case higher modes may connect ports so aff
159. o access the internal modes modes 1 12 Note when performing such kind of calibration due to the sensitivity to numerical error select the menu Settings Preferences Computation and the checkbox show panel for advanced setting Hence set the value Max Att Factor for Evanescent Modes default 3 to 9 This modification is not saved as high values of this factor can compromise the accuracy in evaluating 3D structures The above procedure only works if the travelling modes at the reference plane are not interacting each other namely if the whole discontinuity exciting the modes is planar an example if the result is a 4 port network 2 ports connected to strips say 1 and 2 and two modes say 3 and 4 the above procedure is valid only if any cross connection Y14 is equal to the cross connection Y23 the other parameters are arbitrary Moreover the quality deteriorates when strongly below cut off modes are considered As a drawback there is no direct way to know the order of numbering in the modal ports The above drawback can be avoided by using a 3 standard procedure Procedure 2 3 standards This is more general and only reciprocity of the standards is assumed In this case the first standard is the same of the previous algorithm double Hence select Reactive Load and the two additional standard are two sections of waveguide closed over a short circuit The two Short Distances have to be settled to the distance of the shorting plan
160. o get a calibration file Click over Tools Waveguide Calibration menu only available when two ports are defined in the workspace You have only to load the touchstone output files by clicking over the Thru Standards check box and Matched Load Standard or Short Std respectively Files are loaded and available as data sources in source lists of the Data Browser as folders and of each graph both rectangular and Smith Chart plots Select the right waveguide width used to calculate parameters of the TE10 mode supported from the waveguide By clicking now over the button Create Calibration File a Touchstone calibration file is created and loaded The calibration file will be valid for any subsequent analysis involving the same frequencies and the same excitation structure you won t need to do the whole procedure if e g you want to analyze a 5 cavity filter in the same waveguide In this case you have just to analyze your filter and load the previously calculated calibration file by clicking over the calibration check box Calibration is enabled by clicking over Settings and Enable Calibration at Port 1 and Enable Calibration at Port 2 In this case the plot windows display the calibrated results By default S parameters are referred to the fundamental TE10 mode in each graph you can change this option The calibration quality is somehow dependent on how you have selected excitations namely what could mimic the coax to waveguide transition You
161. o it is not advisable to provide too many frequency points One can test the quality of the circuits either by re inserting the extracted circuit in the circuit simulator or more simply by creating an interpolated data set from any available chart or graph the quality of the interpolation will usually mimics the quality of the extracted circuit If the data source is the current em simulation evaluated by using SmartFIT usually there is no problem as the number of frequency points is reduced as possible Otherwise if data are from external imported sources or the current EM was not obtained by SmartFIT one should perform such a test There are no limits on the electrical length even lines may be modeled within a frequency band The extracted circuit may also be able to extrapolate to some extent the circuit response out of the initial band The model is displayed into a text window where it can be modified by the user and saved The model is in SPICE format Spice model may be extracted even from external network parameters the only restriction being that the structure is reciprocal No validity checks are performed in the present version The model is displayed into a text window where it can be modified by the user and saved The model is in SPICE format For more information about SPICE model implemented please read the paper by M Farina A Morini T Rozzi Broadband frequency domain electromagnetic analysis and automatic extractio
162. o load into the project touchstone files referring to a PEC and a PM simulation Click Next to continue or Cancel to exit the Symmetry wizard Cancel gle Deg Fig 19 Symmetry Wizard The results for the PEC and PMC simulations have to be selected from the list appearing in the Data Browser window in the External Data Files folder by simply clicking on the desired name when prompted by the wizard If the desired data files are not there they can be imported by right clicking over the Data Browser and by selecting from the popup menu Add Data Source The resulting 2N port device will appear as a new data file in the Data Browser automatically saved and available in any chart of EM3DS as Data Source Port numbering of the new 2N port is assigned according to the following convention first ports of the original half structure then mirrored ports IX Mesh options things to know for an efficient use of EM3DS In order to obtain network parameters and field properties for the structure being analyzed EM3DS calculates the volume current distribution within every conductor and dielectric brick defined by the user not the substrate To this end currents are approximated by a set of known functions defined over rectangular sub domains a procedure known as Galerkin method The unknowns that EM3DS calculates are the complex amplitude of this sub domains currents A tutorial about meshing will demonstrate some of the issues
163. o waveguide transitions 4 ee ee A ale aap ee re Ti Sa LH Fig 65 Single cavity filter and strip excitation 58 In the example shown in figure there are 8 layers in layer 1 there is the upper microstrip with its edge port layer 2 is empty layer 3 is the first iris layer 4 empty etc Bottom and top walls enclose the Structure Before or after simulating such a structure you need a calibration procedure able to remove the effect of the coax to waveguide transitions To this aim 2 standards have to be drawn and simulated namely a thru standard and a matched standard or as alternative to the matched one a short standard The thru standard is only composed by means of the two strips and one empty layer total number in EM3DS four layers The length of the empty layer defines the reference plane of the measurement Hence if the reference plane has to be e g 1 cm from the irises the thru standard requires the 2 strips be 2 cm vertically spaced An important underlying assumption is that excitations interact only via the fundamental mode hence keep the planes far enough e g more than half wavelength from the excitations and the DUT Fig 66 Thru standard You should think about this standard as exactly what you would do in a laboratory you take two coax to waveguide transitions and connect them together hence you perform the measurement The matched standard is simply o
164. ocessor devices such as a circuit simulator and a spice model extractor 44 If you want to compare your results with experimental ones simply select the rectangular network plot and from the popup menu select Add Data Source select the file HisSsWOnMis s2p EM3DS Electromagnetic 3D Solver aAA Window r nn Y pa gpm EM3DS loaded D DATA AWR COM EM_Socket MEMResearch Source EM3DS 7 MEMSTutorial EMS Versio D X 3D View Rendering O X General Draw Edit tools Post Processing Graph 2 EBR EM3DS Measured Parameters 2D Graphs Data Graph 1 Data Graph 2 3D Graphs C Angle Deg To Port fi Net Parameters Is I Synchronize Traces Listes Measwed amp From Port 1 Data Source Reference to Port ID DATA Simulazioni MEMS Gallery HighInsulatio fig Pere x 36 405276 GHz y 26 06335 Tools Special Materials Misc Ext Data Files Z Layer 1 IN Layer 2 Layer 3 Layer 4 Layer S H Layer 6 x 160 um z 220 um Edit Mode 3D Mode F ig 52 Standard result chart If you want to change the kind of displayed parameters e g if you want to display s21 remember to change To Port parameter for every one of available Traces Note that in the file HisSWOnMis s2p no data about phase is available hence comparison for other parameters than magnitude of S is not meaningful By accessing to the popup menu you can selec
165. odel Set upper and lower bound for the variable Be careful in setting those bounds the model assumes that the topology of the circuit is not modified namely for example a low pass circuit is not modified into an high pass or something like that the builder extract an equivalent circuit and assumes that only the values of the equivalent components are modified and not their mutual interconnection For example if there is a transmission line avoid those values shorting the line to the lateral walls ground creating an abrupt discontinuous modification of the response Select the Number of Simulations this is the number of actual EM simulations performed by EM3DS over uniformly spaced values of the parameter variable Of course the larger this number more likely accurate is the obtained macro model Consider that in many cases very few simulations are needed and this depends on the kind of structure being simulated the frequency range etc Note that often a broad band simulation is beneficial the macro model exploits information about zero poles of the response and their migration If some pole zero goes out of the current frequency range for a given parameter value the resulting macro model might be useless This is particularly true when optimizing filters Hence if you are creating a macromodel for a pass band filter keep the frequency range much larger than the expected filter bandwidth Some experiments will let you understand this
166. omputational load but in most practical cases it does not result in any accuracy improvement In fact a direct correspondence between the differential gate capacitance due to the charge accumulated in the depletion region and the capacitance due to the field between the gate electrode and the channel exists only under the hypothesis of an abrupt passage from the ionized region to the channel layer and for vanishing drain to source voltage In this case a well known property is that the simple parallel plate expression for the gate capacitance eqn 1 in the following is formally the same one obtains by differentiating the charge in the Schottky contact with respect to the gate to source voltage Owing to these considerations it is generally preferable to assume an effective depth for the depletion layer To this aim it is important to estimate the static gate to channel capacitance per unit length for micrometric gate electrodes the common parallel plate formula E Eal E bott 1 t depl holds quite satisfactory However for submicrometric FETs the contribution to the total capacitance of the side walls and eventually of the top surface of the gate electrode is generally not negligible and equation 1 gives underestimated values 51 Hi aaa tT ttt bott A A A A A A A A A A A A A iy os Ha ttt By simply assuming a uniform circular electric field in the medium embedding the strip and approximating
167. on in the current layer you can select a Slice in layer namely one of the slices used in order to subsection the conductor over its thickness The current distribution refers to such subsection so you can also investigate details of the skin effect Slices are numbered starting from the floor of the conductor Layer display currents for the selected layer All Layers All layers are shown at the same time plot is drawn starting from the lower layer upper layers overwrite lower layers Current Component select if displaying Jx Jy Jz or the total current density Termination it is activated for 2 or more ports if Short is selected short circuit currents are displayed otherwise currents are calculated for the selected port impedance In order to change this impedance just double click over the port Stimulus Voltage specify the voltage V applied to the selected port Show Legend display legend with pseudo colors The legend may be dragged by using mouse it can be exported or copied into the clipboard by using the popup menu Show Values display a status bar where current density value for the position of the cursor is reported When Display Assigned Field in the Assign Magnetostatic Field panel is selected the user can specify at which plane assigned H has to be calculated and displayed The current view may be exported to file as Windows BMP or EMF Enhanced Metafile and copied into the clipboard use the popup menu Mor
168. ons This may be either to the interpolation or to a poor calibration in the EM results e g when simulating antennas or open structures Message Dialog the selected polygon includes collinear redundant vertices Deleting collinear vertices is usually advisable and it may be particularly important when defining ports Delete collinear vertices before attempting to define a port This message is issued when trying to add an edge port to a polygon on a side which includes collinear points Collinear points are not allowed when defining ports Message Dialog In order to add an edge port you have to click over a conductor completely sharing at least one side with the enclosure additionally no more than one port PER SIDE can be added to a SINGLE object click near the enclosure at the desired side This message is issued when trying to add an edge port when 1 you have clicked too far from an edge 2 the edge is not touching the box check out also for round off errors in coordinates 3 you have a polygon which share more than one side with the box Message Dialog This is BASIC Mode license simulation in 2 5D mode is not allowed Calculation aborted as your license does not allows 2 5D simulation Message Dialog The number of ports no longer matches the requirements in the goal list some 119 of the edge ports is probably no longer available Aborting You have probably inserted in the optimization list variables controlling th
169. op the simulation at any time still having available partial results Running may be resumed later some care is needed if calibration is enabled and you stop the program after terminating the computation of the structure but before the calibration process is terminated best to stop the program when a new frequency point is being analyzed If the selected number of modes for the enclosing waveguide is not equal to the number expected by EM3DS a warning window is displayed unless the checkbox Always use suggested modes is selected default in the Substrate and General options window so that you can either modify according to suggestions or continue ignoring the message Alternatively click on the SmartFIT button EM3DS selects adaptively the frequency points for you and estimates the full band response Now you have results that you can plot save and export In any context by pressing F1 key help is made available VII Perfect Magnetic Conductors PMCs and symmetry planes Since EM3DS 8 PMC planes are implemented A PMC 1s a plane where tangential magnetic fields and orthogonal electric fields are zero namely dual conditions with respect to standard electric conductors PMC are useful to handle symmetric structures and hence to save computational time and load In EM3DS you can set as PMC either top and bottom walls as well as two side walls of the conclosure see the brown walls in the figure Fig 14 Two side walls are PMC PMC
170. optimized for whatever circuit and this is why EM3DS specifies a list of frequencies and not a range for the optimization If a Macro model see the previous paragraph is available and a single variable is selected in the optimization coincident with the one over which the macro model was created the checkbox Optimize Macromodel is available in this case the macro model is used during optimization without additional EM simulations The optimization is very fast but results have to be finally checked with a full wave simulation Moreover if the variable is tunable the results are updated in real time in response to the tuning XXX Tuner 68 Once geometry is defined by means of Variables select in the optimizer dialog which variable should be tunable see previous section At this point either select Tools Tuner or click to the tuner icon in the data browser or in the toolbar The following dialog appears ki Variable Tuner mm Min Nominal 100 Mominal d I l l I l I I l ot I l l I l I Il k q oti I l l I I l I I l ot Aae S S I l I I W Real Time Update of variables Fig 76 Tuner Panel By moving the corresponding sliders variables and hence the structure are modified accordingly and the geometry updated in real time or upon pressing Update Variables according to the selection of the checkbox Real Time Update Variable can be reset by clicking to Revert to Initial Values If a macro mode
171. or a list of built in functions to be used in expressions see the list of the Appendix Layer thickness the thickness of the selected layer Note that any conductor drawn in the layer has its thickness In 2 5D mode the layer thickness of odd layers is only used to evaluate the ohmic losses of planar conductors in that layers Layer name comments insert here a string to label the layer A remainder of the layer name will appear in the Data Browser when an object in it is being edited Number of y subsections only 3D mode Conductors and dielectric bricks in EM3DS are modeled by means of volume currents In the vertical y thickness direction they are modeled as piecewise constant This number say Ny sets the number of vertical pieces used to model currents flowing within conductors and dielectric bricks possibly placed in this layer see figure This slicing has no meaning in the 2 5D mode and so it is not accessible in that mode y Y subsections Embedding layer X Fig 10 Meaning of parameter number of y subsect Non Uniform y subsections only 3D mode the first and the last slices may be selected to be thinner than the others see figure below by checking Non Uniform In this case the number of slices is minimum 3 and the Non uniformity factor allows to select the ratio between the size of such slices and the total thickness For example Non uniformity factor set to le 3 for a layer having 1 um thickness implies that the
172. ou can also double click on an object in order to get a dialog window where to select position mesh material etc A good idea might be to parametrize your structure define parameters first see Parameters and Variables and then use them when defining position size and vertices of your shape Any update of the variables automatically updates your structure Moreover this way you have full access to the internal Optimizer and to the Tuner as well as to the Macromodel builder Undo Alt backSpace and Redo alt Shift Backspace buttons are available In the status bar dimensions and position of the object or of its circumscribing rectangle are displayed By clicking over the menu Action Drag Mode or its counterpart in the toolbar drag amp drop is enabled so that the user can easily displace objects by mouse not working for groups only for single objects The popup menu allows changing position and dimensions of the selected conductor changing the mesh options namely how conductors are discretized changing the conductor resistivity selecting the position of the reference de embedding planes checking what shapes are in contact with the selected one 18 Add ports the structure just drawn has to be excited by some kind of source in order to obtain a network description of its behavior Excitation is applied by means of Ports You can add Edge or Via ports To this aim just select menu Action Add Port or Action Add internal Horizo
173. ous versions too allowing different versions to coexist in the same system Message Dialog Running Server is for an older version of EM3DS Since ver EM3DS 8 each new version of EM3DS requires its updated license manager Note that e g License Manager 8 will work for EM3DS 7 too Message Dialog the number of ports of the two network files even and odd MUST be equal your current selection is invalid This error is reported by the symmetry wizard it indicates that files selected for recovering the full port response are inconsistent Message Dialog Cannot start computation an edge port is attached to a magnetic wall PMC Please remove the wrong port or modify the enclosure by Settings Analysis and subs Settings A port is defined by means of an E field orthogonal to the conductor section hence it cannot be defined between a conductor and a PMC as E field orthogonal to PMC is zero Finally there are specific messages pertaining to the importing exporting filters Moreover set of messages refers to the GOS file namely the file where graph settings and formatting information are saved GOS files are ascii files and hence EM3DS also indicates where the error occurred This kind of error has no effect and only graph formatting legends axis limits etc may be lost The most common error is the one issued whenever an external data file is not found and some graphics refer to that file Recall that EM3DS seeks for external data fi
174. ove formula do not apply the Scale resistivity option to via conductors scaling is made over the wrong dimension While in the standard 3D mode skin effect is modeled by subsectioning the conductor thickness see p 6 in the 2 5D mode the only way to add skin effect is by checking the force skin effect check box the resistivity is scaled according to the well known skin depth rule The problem is that such a rule assumes the current density flowing mainly at one side of the conductor this hypothesis is usually barely acceptable for microstrips but it fails e g in stripline structures The user should keep in mind this set of limitations when using the above options Note a typical error see FAQ 4 is assigning a non zero resistivity to thin conductors in this case of course the resulting conductor resistance becomes very large and no signal is carried by the conductor Do not assign non zero resistivity to conductors lying in thin layers unless Scale Resistivity is selected and Scale to thickness parameter is properly selected Assign Color provides a tool for assign a color to the material if in active layer specifies the color of the material when it is in the active layer and its color on the 3D window while if in other layers specifies the color in the editor if the shape lies over a non active layer EM3DS Electromagnetic 3D Solver ME Window EM3DS loaded C DATA OIdShapeE d ShapeEd1 3 TestDR EMS Versi X EE 3D
175. over direct contact a highly lossy substrate like a semiconductor in this case the suggestion about the involved modes is known to be underestimated The same consideration applies whenever frequency dependent parameters for the substrate are used no problem for properties of conductors and dielectric bricks A warning is issued in the Message Window in the above cases The simulation may be really fast for several frequency points The Asymptotic information is available until the user modifies the structure or the mesh settings Note that if you change the Stop Frequency you are asked if updating the mesh or not If you select to update the mesh the Asymptotic Information is discarded If you believe that the present mesh is good enough for the new stop frequency it is better to leave the mesh unchanged Usually a look to the current distribution helps to see if mesh is satisfactory or not by rising the frequency of the displayed current it may happen that standing waves become more and more coarsely described This is a symptom of insufficient mesh The best way to verify the accuracy of a mesh selection valid for any em simulator is performing a new simulation with a denser mesh and evaluate how results are modified The only structural modification that you can do without losing the Asymptotic information is changing the resistivity of a conductor or the dielectric permittivity of a dielectric brick or even 53 changing the natur
176. pe in an even via layer Please remove the wrong port or switch to 3D mode by means of the menu Settings Analysis and subs Settings In 2 5D mode the odd indexed layers 1 3 5 are considered to host only standard thin conductors while even layers only via conductors Standard thin conductors are modeled by surface currents Jx and Jz so that only Edge ports which are calculated by evaluating currents Ix and Iz can be attached to those conductors On the other hand via conductors are modeled by just volume Jy and consequently only via ports may be attached If any of the two conditions is violated in 2 5D mode the engine will stop the calculation with this error message Event WARNING de embedding plane larger than half wavelength check de embedding line parameters Possible failure of the extraction of parameters for feeding lines however this failure does not affect the accuracy of the calibration Event Caution interpolation is made over a large set of input points interpolation might be poor Interpolation either during a SmartFIT run or in post processing is performed over a too large data set This may raise numerical issues One should attempt to reduce the number of input points below 40 50 Event Caution either interpolation or EM solution are not reliable at GHz Results obtained during interpolation or SmartFIT for a reciprocal circuit violate PR conditions namely does not respect passivity conditi
177. point The value of the Interpolated points in Macromodel is the number of frequency points where the macromodel is available When the above parameters are settled just click Create Macro Model At the end of the simulations the macromodel is available in any chart if the parameter is selected as tunable in the optimization window see the next paragraph about the Optimizer you can tune the variable see Tuner and see the response evolution in real time The optimization can be performed over the macro model You still have two additional options Linear Interpolation if selected the interpolation is linear otherwise is cubic spline The modification affects the evaluated macro model in real time no need to re calculate Apply correction by default the interpolated macro model is obtained by Y admittance matrices If there are poles around the poles the response can be poorly interpolated creating unphysical spikes When Apply Correction is selected EM3DS automatically detects poles and tries to correct the possible response deterioration by exploiting results from a Z impedance model If it is detected a discrepancy between Y and Z interpolation greater than the relative correction threshold Z response is assumed around the pole The correction usually removes spikes around poles but should not be used if in the selected frequency range there are no poles at all In any case even this option has a real time effect no n
178. portant because the additional conductor in the sense layer affects the computational load and in spite of this its mesh only affects the resolution in viewing the field and the quality of the radiation diagrams Hence the user can and should check and eventually modify its mesh properties according to the needs NOTE if you add any object in layer 2 layer is forbidden if it is a sense layer when removing the sense layer layer 2 is removed at the same time along with all object hosted Anyway a warning is issued Once the E field is known in the sense layer equivalence theorem is used Basically it is assumed that the cavity radiates over a perfect conducting plane Top cover Fig 107 Top of the box surrounded by a perfect conductor By means of the equivalence theorem the tangential E field across the absorbing boundary is replaced with Magnetic Sources M Combination of effects E M t Equivalence amp Theorem oo S lt S 104 O Fig 108 Equivalence Theorem and Image Theorem are combined across the top boundary to evaluate the radiated field The image principle gives the equivalent problem where a magnetic source is radiating in free space This is done by using the magnetic potential eel ae P P F M x de an p ameng dx dz 4r r 22 and the far field expressions relating the E field with the magnetic sources thee bo oes E oe gt
179. problem 3 User defined size the user selects manually the enclosure size While selecting above option 1 2 or 3 will discard data previously calculated the correct calibration near resonance checkbox only acts on the post processor so that you can ever see the response obtained with or without the correction possibly you have just to update existing charts by any modification in the displayed measurement Hence this correction may also be enabled for pre existing simulations If the lower frequency of analysis is already too close to a multiple of lambda the correction will not work and a warning is issued As final note when using SmartFIT this correction may force SmartFIT to run quite more simulations To Probe Further Meaning of error network file Names to the error networks are assigned according to the following conventions DL the selected filename for the output file for the de embedding network for the Left hand side ports DR for the right ones DT for the top ports and DB for the bottom ones Fig 63 Example about meaning of de embedding files Let us consider an example on how these files could be used in principle If the name of the default raw output file is Ytest y5p this is signalled in the Event window at the end of the processing the de embedding algorithm produces DLYtest y4p de embedding network for the left ports DRYtest y2p for the right port DTYtest y2p ecc The numbering of ports for DL
180. r Syntax error in using the Circuit solver the parser was unable to find the value for the given component Message Dialog Missing SUBCKT symbol at line XX Circuit solver Syntax error in using the Circuit solver any component labeled by string beginning with X or N is treated as subcircuit and has to respect subcircuit syntax see p 54 Message Dialog No name specified for subcircuit at line XX Circuit solver Syntax error in using the Circuit solver any component labeled by string beginning with X or N is treated as subcircuit and has to respect subcircuit syntax see p 54 Message Dialog Missing Length Zo Effective Dielectric value at line at line XX Circuit solver Syntax error in using the Circuit solver any component labeled by string beginning with T is treated as transmission line and has to respect transmission line syntax see p 55 Message Dialog Node XX is floating Circuit Solver Label XX indicates a floating node Message Dialog No Port Specified Circuit Solver At least one port has to be connected to the circuit Message Dialog Merge Algorithm Failed At the moment Merge does not work properly if vertices of a polygon lie directly over one of the side of the merging polygon a small partial overlap allows to circumvent such a problem Message Dialog Be careful the control plane is defined outside the channel its co ordinates should fall in the channel The control plane is the plan
181. r by layer hence if layer 1 is selected only currents flowing across objects in layer 1 are displayed The parameters appearing at the bottom of the window are Number of Samples Sampling points over the box used to plot the surfaces if the number of points is insufficient for a given structure details may be lost or visual aliasing may appear Animate Animation Animate current view vs frequency magnitude or vs phase using phasor technique at the specified frequency or in time The time animation allows to get images about transients and makes use of the assumptions explained in the Time Domain in EM3DS section and it is quite time consuming When selecting Time in the animation time domain 81 current is shown and an additional panel is made available Now Showing reports the time instant of the current display Here one enters the time interval the number of plotted points in time there are no restrictions By default the stimulus is assumed to be 1 over the whole frequency band if frequency points are equispaced this equivalent to a finite pulse whose width is determined by the upper frequency point 1 fmax and which repeats after a time correspondent to the lower frequency point 1 fmax However it is possible to enter any frequency dependent expression to create your own stimuli The actual stimulus is displayed when checking view stimulus A Kaiser Beta windowing is applied by default in order to reduce the ripple indu
182. r right corner all objects included in the selection rectangle will be selected Once selected objects can be deleted Del key moved by arrows key on the keyboard copied cut pasted etc Mesh options and Resistivity in the menu resistivity Material Specifications are applied to all selected objects Note that buttons Apply to all objects will apply the setting to any item in the project Coming back to our editing resistivity for items in this and the next layers has not to be scaled as these layers have their actual thickness Hence just specify 2 5e 8 Ohm m as resistivity deselect Scale Resistivity Same identical steps have to be followed for layer 3 placing two rectangles with same dimensions and same resistivity working as anchors for the bridge and lateral ground planes for the CPW The same expedient used above to save time may be employed Note that these conductors are also in contact with the lateral box walls that is an ideal ground Same identical steps have to be followed for layer 4 Here we have also to add the central CPW conductor the signal line Dimensions are 280 x and 420 2 gw sp z while position is 0 x gw sp z this ensures that the line is placed in the middle if you change spacing Conductor Dimensions Dimensions a 10000 080 De 0 O00 D2 0 Displace Position Top left camer eh OO Zlowesp Mesh Op Right 160 Resistivity Bottom z 60 Units um z W Metric Fig 49 Position a
183. res EM3DS to test if an object is completely contained into an other object in the same layer what would produce a complete failure of the analysis and possibly to discard it Usually disabling the automatic mesh while importing external sources is recommended as often some additional editing is needed in order to simplify the structure During import actually only POLYLINES of DXF and Boundary of GDSII are handled so as to produce objects namely conductors in EM3DS rectangular polygons are automatically converted in rectangles allowing to add ports Other entities are only plotted in the editing window DXF Image so to e g help to redraw some structure The DXF Image is available until a new file is selected or the menu item Edit Clear DXF Image is selected Importing BMP file has the effect of producing a BMP image to be e g used as guideline in drawing You can clear the BMP Image by selecting the menu Edit Clear BMP Image Link to BMP and DXF images are not saved in the EMS file Export Options Layer to be exported Export Shapes as f Lines Closed Polygons Units cm IY Metric Cancel Fig 103 101 DXF Export window Files can exported as Autocad DXF or GDSII by selecting File Export A checklist on the left hand side allows selecting which layers have to be exported Layer Ground is just a layer describing the box When exporting in DXF format shapes are either translated into li
184. rmed via 20 Log mag RI means the data are in rectangular form real imag 4 The network parameter matrices are in row major order except for two port matrices which are in column major order 5 Each network parameter is a complex number that is read as two sequential real numbers 6 Each line may contain a maximum of four network parameters 8 real numbers If the matrix contains more than four network parameters per row i e it is larger than a four port then the remaining network parameters are continued on the following line 7 Each row of the network parameter matrices begins on a new line 8 The first row of a network parameter matrix is proceeded by the frequency at which the data was generated 9 The filename extensions by convention are slp s2p s9p s10 s11 s99 The network data syntax is lt freq point 1 gt lt row 1 gt lt row 1 cont gt lt row 2 gt lt row 2 cont gt lt row n gt lt row n cont gt lt freq point m gt lt row 1 gt lt row 1 cont gt lt row 2 gt lt row 2 cont gt lt row n gt lt row n cont gt where m Number of frequency points n Matrix size Example file for a two port Example Data File Using Format GHZ S RIR 50 Freq S11 S21 S12 22 f1 ReS11 ImS11 ReS21 ImS21 ReS12 ImS12 ReS22 ImS22 f2 ReS11 ImS11 ReS21 ImS21 ReS12 ImS12 ReS22 ImS22 f3 ReS11 ImS11 ReS21 ImS21 ReS12 ImS12 ReS22 ImS22 79 XXXIII Post Processing Creatin
185. ronize Traces ggg ves enon Traces measured v A T Circuits From Port fi DataSource pA 11 le ae J OWA LA SSIMUIGZIONINIC MS ery Snignihsulatol g g Tools Materials h Reference to Port ag ools S pecial Materials x 34 132915 GHz y 14 762184 gi Ext Data Files gt DADATAMAWR C Z Layer 1 IN Layer 2 Layer3 Layer 4 Layer5 H Layer6 ZZ Layer SY Layer 8 x 150 um z 12 um Editing mode 2 5D Mode You can find this example in MEMSTutorial25Dmode EMS DATASSimulaz gt XVIII Dielectric Bricks and resonators material specifications Dielectric bricks are dielectric regions not extending up the enclosure boundaries Hence dielectric bricks allow to model dielectric discontinuities EM3DS does not distinguish conductor and dielectric bricks if a dielectric is being specified in place of a conductor the obtained currents are mainly displacement currents In order to specify a dielectric brick one has to add a conductor rectangular polygonal or circular right click over the conductor and select Resistivity Material Specifications either from the main menu Action or from the popup menu In the dialog box one has to select the check box is a dielectric specifying the relative permittivity and changing the default resistivity Note that the relative permittivity cannot be the same of the embedding medium a waning is issued and when trying to perform computation also a
186. ructure by specifying position and size of the conductors Let us select layer 1 from the lower left panel Hence select the Draw Edit tools panel and select the button Draw Rectangular Conductor Dielectric Brick Alternatively select the menu Action Add conductor By the first click over the working area you set the upper left corner release the mouse button and move the mouse up to click where you want the lower right corner In the lower bar information about the position of the mouse and the size of the rectangle being drawn is displayed This is not very important as we are going to specify exactly the position and the size of the rectangle By the way you can click after over the conductor this way the shape is selected and you can displace it by the keypad arrows If shift if kept pressed you can also change the rectangle dimension Moving the rectangle by drag and drop may also be enabled by selecting the button move conductors and then by dragging any of the available shapes Right click over your rectangle and select from the popup menu Dimension and Position or simply double click over the rectangle to access directly this window Actually a very good idea is to parametrize circuits by defining a set literal of parameters and then using them to define size and positions see Variables and Parameters In the latter case remember that any modification you make moving directly or resizing the sh
187. ructure is analyzed In the Project Data window menu Settings Analysis and set the Involved Modes to numbers at least equal to those recommended otherwise accuracy at the higher frequency range is lost Message Dialog Unable to start computation no port specified You need to specify at least one port in order to analyze a structure fatal error Message Dialog Hint via ports are not de embedded no de embed will be performed at via ports In the present version via ports are not de embedded Message Dialog The suggested value for the number of modes to be used in the MoM matrix doesn t match the current setting Do you want to verify the current settings EM3DS uses the modes of a rectangular waveguide the one represented by the sides of your workspace in order to build the em solution The number of such modes needed for the solution is directly related to the minimum distance between mesh lines forming the mesh cells Hence pay attention to this parameter to reduce the computational load The number of needed modes is usually equal to the ratio between the waveguide size and such a distance If this message is being displayed the currently selected values do not agree with this rule By selecting Yes a window is displayed where you can select the button use suggested values Hence you will able to start the computation Message Dialog Warning the dielectric brick should not assume the same permittivity of the embedding
188. s available ir ff al r Aun Us A Pn A A Fig 95 Linear Circuit Solver window 90 There are few syntax rules to be respected comments begin with symbols or or ground is indicated as node 0 or gnd ports are defined with respect to ground the first character is reserved to understand what kind of component you are dealing with R resistors G conductance L inductor C capacitor X subcircuit N negate subcircuit P port For example Rai is considered a resistor General 2 port components have the following syntax lt Component gt lt Node1 gt lt Node2 gt lt Value gt lt Units gt where lt Units gt is optional For example R110 100k Indicates a resistor having 100kOhm between node 1 and ground Only the first character of the unit parameter is considered hence k is for Kilo m for milli M for mega etc Only units are case sensitive You do not need to write directly the above expressions you can select from the menu the desired component a string is added correspondingly Hence you can edit nodes and values according to your need Transmission Lines have the following syntax TL lt n1 gt lt n2 gt lt L gt lt Zo gt lt Eeff gt where lt n gt are nodes lt L gt length in meters lt Zo gt in Ohm and lt Eeff gt effective dielectric permittivity Note that no unit has to be specified for this kind of component For example TL1 1 2 1e 2 50 0 4 0 Is an
189. s has the effect of making the device non reciprocal Gauss Solver is invoked regardless the user selection resulting in slower simulation and higher memory requirements Material Specifications 0 0001 ond Resistivity Ohm m W Add controlled source Controlled Source Settings s Control Layer Transconductance 450 ms rnin 232 B E Sree ee 0 ee Current Direction Control Plane x 5 375 um e Co 2 Assign Calor D ifin active layer Fin other layers Fig 57 Resistivity Material Specifications dialog box Adding controlled sources In the same window there are a few additional options As discussed in the previous section by selecting Scale Resistivity check box you can require that a thin conductor have a finite conductivity this option may be useful to evaluate conductor losses while keeping a conductor thin so as to avoid the additional computational load that a thick conductor would require In this case the conductor resistivity is replaced according to p gt p t desired t actual where taesireg 1S the thickness we want to simulate and is the value entered in Scale to thickness and tatua IS the actual thickness of the conductor i e the one of the embedding layer This is an 49 approximation that may be useful to reduce the computational effort whenever finite thickness is believed to play a limited role this reduces the analysis to the one commonly adopted by 2 5D approaches Due to the ab
190. s of the curve with respect to the x axis Mirroring available after placing the item simplify drawing arbitrary structures XV Slanting line By clicking over Action Add Slanting line the user can add a rotated line the amount of rotation is defined by the angle with respect to the x axis Dimensions and position are specified as in standard rectangular shapes Internal A adius Set Center 625 sir Circle Divisions Approx to polygon Fig 37 The Add Curve window 33 Slanting Line E4 Angle 45 Deg Bottom left vertes positio 2 5000 ul 5000 eal F ig 38 The Add Slanting line window XVI Merging shapes As we have seen previously where two shapes intersect intersection mesh lines appear Sometimes this may produce overmesh in the resulting structure By merging the two shapes and by using a uniform mesh the user may obtain simple and effective mesh Merging is performed by selecting the Merge command from the popup menu or from the Action Menu if an object is selected the user is required to select one more object to be merged Rectangles including ports cannot be merged Note that the algorithm may work not properly if vertices of a polygon are exactly over sides of the other In such a case it is sufficient to displace by a very small amount one of the two shapes so as to guarantee overlap If Merge fails and resulting polygons are corrupted use the undo button Even polygons including holes may be
191. s selected In order to modify properties of a trace just make this trace active from the list box traces and then perform your modifications By accessing to the popup menu you can select Zoom by mouse or Pan by mouse in this case by dragging the mouse you can either zoom or pan your plot By default parameters refer to the EM Simulation however you can add several Data Sources namely S Z or Y Touchstone files This way you can e g compare measured and calculated data or simply compare several simulations Data sources added within a plot window are also added to the Data Browser and are available from any plot window De embed option is possibly available only for the current EM Simulation The user can delete traces Data Sources are only deleted by the Data Browser The Delete Trace and Edit Trace menu only affect the selected trace Graph 2 Add Data Source Touchstone file Set Axis Limits Add Trace Add Interpolated Data Set Add Interpolated Data Set from Z Edit Trace Properties Trace 1 Plot Options Add Bitmap as Background Export EM Simulation To File Cc Export Macromodel simulation to File Copy View to clipboard as Meta Copy View to clipboard as Bitmap Ctrl C Save View to File Refresh Data during processing Zoom by mouse Pan by mouse Unzoom Restore plot Ctrl U Help C Angle Deg Measurement s J Synchronize Traces Poe To Port m
192. sh Data during processing oO QQ Help H Tr E D Parameters c f Traces s21 Fr Era 7 Mae De E mbedder races Trace 1 ata Source Current Data Source Current EM Simulation Reference to Fort To Fort From Fort 1 11 2 Fig 84 Smith Chart An additional chart for antenna measurement is the Polar Plot Polar Plot 4 EndFire Array EMS Traces Antenna Measuremen Ephi sweep theta phi o deg Frequency as ajon W Excite multiple ports Port settings Fort M Voltage fi W Phase qq Deg Current EM Simulation Fig 85 Antenna Polar Plot 77 Even in this case the antenna plot is available only if a sense layer was added to the project In particular in the present version it is plotted the far field one polarization normalized to its maximum value in the displayed chart Several of the above features are also available when displaying De embedding Line Parameters menu View De embedding Line Parameters In fact when de embedding information is available you can display the characteristic parameters of the feeding lines namely characteristic impedance propagation and attenuation constant etc Data refers to left right top and bottom ports whenever some reference plane has been defined Results about the displayed parameter can be exported as text data file by clicking over the menu Export to file as text appearing when right clicking over the graph A few restrictions apply
193. sity raise rapidly Hence consider that generally a low order polygon provides fast and reliable results and that there are a few cases where the number of vertices is worth to be raised e g circular dielectric resonators XII Rings By clicking over Action Add Ring Cond rings approximated by a polygon are added EM3DS displays the window reported below 31 l OF Internal A adius Set Center a e o a EOF re Cancel Help dila Circle Divisions Approx to polygon a Strip width E25 Lim Fig 34 The Add Ring window It works as for circular conductors see previous section Internal radius and strip width have to be specified XII Circular spiral By clicking over Action Add Circular Spiral Cond the user can add spirals Circular Spiral Internal Radius J Set Center 625 al Number of turns Spacing 3 0 B25 Strip width 625 um Fig 35 The Add Spiral window Several items of the dialog box are common to those appearing when adding a circular conductor Additionally the user has to select the spacing the strip width and the number of turns that is not necessarily integer 32 Fig 36 Round spiral in EM3DS XIV Curve By clicking over Action Add Curved Cond the user can add a curvilinear bend to a conductor dielectric Several items of the dialog box are common to those appearing when adding a circular conductor Additionally the user has to select the start and stop angle
194. st 2 direction 5 3 Cache sym Into Fig 13 Substrate Information and General Options window Frequency and computation options Define frequency list allows to create a list of frequencies where the device has to be simulated If the check box Asymptotic Approximation is selected EM3DS computes and stores information about the frequency behavior of the Green Function needed to build the solution and uses this information in order to dramatically speed up the computation over the remaining frequency range In fact only the modes indicated in the Involved modes panel are used over the remaining frequencies The lower the involved modes the lower the computational time More modes means more accuracy however generally no more than 10 modes both in x and z direction are needed to obtain excellent results Generally 3 5 modes are enough The computation may be really fast for several frequency points The Asymptotic information is available until the user modifies the structure or the mesh settings if you change the Stop Frequency you will be asked if updating the mesh according to the new wavelength or not By updating the mesh the Asymptotic Information is discarded If you believe that the actual mesh is good for the new Stop Frequency it is better to leave the mesh unchanged so as to use the stored asymptotic information The only structural modification that you can make without loosing the Asymptotic information is chan
195. substrate You cannot ignore this message For EM3DS a dielectric brick having the same permittivity as the embedding substrate is a non sense and calculation will be aborted Message Dialog Warning the dielectric brick cannot assume zero resistivity You cannot ignore this message Set correctly the dielectric brick resistivity Event Warning the scale resistivity option should not be used if the layer embedding the conductor has more than 1 vertical thickness direction subsections Ny gt 1 Checking Scale Resistivity option in Resistivity Material Specifications of a shape is nearly equivalent to switching to a 2 5D point of view This is not compatible with rising the number of vertical subsections Ny Event Warning the imported structure seems to be rather complex editing the structure before starting computation is recommended The file contains more than 50 items This is not a problem However if this is the result of an import e g GDSII you could want to consider editing of the structure before mesh or running the simulation Event Unable to find file XXX Command CMDLOADDATA load data source file Ignored Simply your EMS file references to a link to an external data file Touchstone that EM3DS was unable to find EM3DS looks for either in the specified path or in the same directory where the EMS file is located This is not an error Only plots containing that information are not displayed Event Error w
196. sults Moreover calibration plane may be shifted at the port plane by selecting Reference To Port check box S parameters are always exported normalized to 50 Ohm however the user can change the normalization of the displayed parameters by double clicking over the ports If the active trace in the 2D charts is the one of the em simulation plot is automatically updated otherwise just select the em trace and force updating by e g switching temporary from dB to natural and vice versa The selected impedance also affects the visualization of the currents whenever visualization is made over load and not short circuit as default If a waveguide calibration set is enabled see previous paragraph S parameters are displayed as normalized to TE10 characteristic impedance default or 50 Ohms Note Whenever normalized to TE10 S parameters exported in Touchstone format are indicated as to be normalized to 50 Ohm While this is not correct in principle if you derive z or y parameters from such a file you get wrong results this expedient was needed for compatibility with some commercial software packages available You can plot several traces in the same plot just right click over the graph and select the additional menu item Add Trace A new trace is made available and appears in the trace list Any change you make e g the kind of network parameters the user has selected just affects the current trace unless Synchronize traces i
197. t Ports EM3DS allows three kinds of ports edge internal planar and via ports either internal or ground referenced Edge ports may only be added to conductors sharing at least one side with the enclosing walls in order to add an edge port click over corresponding button or Action Add Port in the main menu and then click over the conductor where the conductor touches the lateral wall Results in terms of network parameters are ground referenced Hint if you draw a rectangle larger than the box EM3DS can automatically cut it in order to fit it into the box just open the Conductor Dimension window right click over the rectangle or menu Action and click over the Apply button 62 Conductor Top View NEON EN ELIE EU EN TU TOI EN EID LEU EN EN TICE EE EIT DEA EN TUTE EN IE DE EU EN DUDE EN EU EIE IEEE IE EN EU EEE EE PEA EU EU i i DIU EATEN EU i i i DIE EIEN EU ie i IEEE EIEN EU i ie i EIU IEEIE Fig 69 Schematic of Edge port Ports are actually impulsive impressed fields lying along one direction and not vanishing over an infinitesimal gap In 2 5D working mode edge ports can only be added to planar conductors namely conductors located in layers having odd index Internal planar ports are ports that can be added nearly everywhere to any conductor the only restriction being that only one internal port can be added to a given object if the circuit needs additional internal ports split the circuit in additional co
198. t Zoom by mouse or Pan by mouse in this case by dragging the mouse you can either zoom or pan your plot If you want to see a more realistic view of the structure go on the Data Browser right click and select from the popup menu Add 3D View Rendering a window showing a 3D view with lights and impressive visual effects that you can rotate zoom copy etc appears You can also zoom into stacked structures to see internal details Also currents may be displayed using this powerful post processor by the Data Browser select Add Current 3D Graph Rendering You can add other 3D views and Graphs and to access them by the Data Browser When creating or reading a new file Graphs are discarded but the 3D Views are still available you can delete them by Del Note that not all functionality of these windows are guaranteed to work in any computer as they are hardware dependent and your Graphic Card may not support all features You can also plot vector currents on these view Design of the actuated switch follows similar lines only now the bridge should be moved from layer to layer 2 so as to be over the silicon nitride layer 45 EM3DS Electromagnetic 3D Solver Tm a EM3DS loaded D DATA AWR COM EM_Socket MEMResearch Source EM3DS 7 MEMSTutorial EMS Versio PON IY Minar J 3D View Rendering 1 2 009E11 Ar Th a a A Hyera AD 44444e A 2 ae EN PPP DP GOEL OD R R ILR A LIK ARLOKA
199. t full EM3DS functionality Multimode calibration algorithm now it is possible to import externally defined termination conditions Since Version 9 2007 EM3DS featured e Internal Planar Ports Ports can now be added everywhere also off ground e Tuner Variables can now be tuned for parametric simulations e Scripting An Object Oriented Pascal OOP Editor Compiler is embedded in EM3DS and allows to customize the program some special functions allows to read EM3DS results modify and create variables run simulations and optimizations Complex variables are available as well as functions to handle them Scripting functions are updated in minor releases of 9 x e Sense Layer A sense layer can be created and handled automatically to see E fields in a plane The sense layer also allows to calculate radiation features of an antenna such as far field and radiation patterns e New charts A polar plot for antenna parameters far field is available also in 2D rectangular plot and in a 3D surface plot with rendering e A general calibration algorithm for multi mode waveguide calibration This is an advanced feature added for scientific purposes enabling the calculation of the Generalized Admittance Matrix GAM of a given waveguide structure This calculation can be used to split a structure by cutting it everywhere e New measurements for antenna applications e Multimedia documents link to multimedia file into a project e Enhanced Editor Most
200. ta Files Fig 21 How mesh cells are created Hence try to set up a more regular mesh by changing the shape Mesh Options see also the following To Probe Further section Red lines highlight mesh lines involving a very large number of modes more than 500 In this case displacing mesh lines is practically necessary Mesh Options Cell size mm 3 077200 Cell size z mm 3 0772007 Edge mesh distance x unitless i G E dge mesh distance 2 unitless E W Add Edge Mesh x I Uniform Mesh Add Edge Mesh z No shadow mesh cells Apply to all abjects i Cancel Help Fig 22 Mesh Options window pressing OK the mesh options will be applied to all selected objects Pressing Apply to all objects the selected options will be applied to any object in the project FAQ 4 No signal seems to be transmitted between two ports that are actually connected through a conducting path There are several sources of this kind of error Let us see some of the most common errors l you have assigned a finite resistivity to your conductor path e g 1 7e 8 copper but the conductor is placed in a very thin layer e g fraction of a micrometer As the thickness of the conductor is the same of the embedding layer the conductor resistance is very high so not carrying or at least attenuating any signal As a solution you have either to correctly setup the layer thickness in this case keep in mind the recommendation in
201. ted signal would be transmitted by the structure in this direction Up to ver 4 2 of EM3DS it was important to ensure this continuity by directly overlapping items in contact and EM3DS automatically resized contact shapes so as to guarantee overlapping In the present version this is no longer necessary as the mesh algorithm will automatically recognize this situation and generate the right expansion functions ensuring continuity This simplifies greatly drawing structures especially structures involving general polygons However it is ever possible to directly overlap contact shapes even if this usually results to a slightly higher number of unknowns Even the automatic resize procedure may be enabled by selecting Settings preferences Editor from the main menu and by selecting the check box Auto resize rect for overlap However it is very important that a project be developed ab initio either with the auto resize enabled or not the mesh algorithm mostly for backward compatibility produces a different mesh This setting is embedded in the EMS file command AUTORESIZE EM3DS may be unable to reopen results for a structure developed partly with auto resize enabled and partly not Note whenever Jx or Jz are not defined over one shape shapes adjacent in contact to the conductor dielectric for which Jx Jz are not defined should overlap such a conductor dielectric In fact only in this case automatic mesh algorithm is unable to set up
202. ther on a grid or not but the hypothetical grid may be used anyway as reference for edge mesh setting Edge lines are static i e not updated with frequency There are the Shadow Mesh Lines these are static lines produced at the intersection between different shapes even if shapes are on different layers in this case a shape seems to project a sort of shadow Vertices of a polygon also produce shadow mesh lines on shapes lying in some other layer In multilayer structures using polygons with very large number of vertices may create overmesh In version 8 shadow lines produced by objects in different layers and separated by at least one layer may be suppressed so simplifying the mesh when the two layers involve complex or non Manhattan shapes This is done by acting on a local option to be selected in the mesh options no shadow mesh cells of the object In practice if such an option is selected for a given object the mesh of the latter will not be affected by the presence of objects placed at least one layer away Of course in this case the user should ensure that mesh manually settled be satisfactory for correctly describing the coupling with objects in different layers Note that if two objects are in adjacent layers the shadow mesh suppression has no effect or the current continuity would be violated This is for example the case of vias polygonal vias should be always approximated with a lower number of vertices T
203. tly obsolete An approximate procedure is included and it is the most economical one the user can try to make the upper conductor as thin as possible e g 0 0001 um while scaling the resistivity so as to simulate a thicker conductor namely to keep invariant the resistivity This is done automatically by selecting Scale Resistivity in the Resistivity and Material specifications dialog box select a conductor then right click in order to see the popup menu and by entering in Scale to thickness the desired hence the real physical thickness the conductor should have While approaches 1 and 2 are rigorous in principle actually 2 requires some hypothesis and restriction about the possibility of accessing the physical point where the parasitic capacitance appears approach 3 is based on a number of assumptions and basically bears resemblance to switching from a full 3D point of view to a classical 2 5D Nonetheless conductors are not infinitely thin and vertical currents are evaluated as well Hence instead of using approach 3 consider to switch your project to 2 5D working mode This would save a significant amount of time and memory space while raising the robustness Approach 3 should only be considered where some kind of mixed 2 5D 3D approach should be used e g planar structure still involving some true 3D detail In standard microstrip design approach the 2 5D working mode is recommended as well as for a large class of CPW while in MMIC
204. to probe Further 2 p 6 or to select scale resistivity from the resistivity material specif Window and set the desired thickness in the scale to thickness entry 2 You have two shapes in your path that are visually in contact but actually they are not In order to verify if two shapes are actually in contact simply select it and from the popup menu choose Highlight contact shapes Shapes actually in contact with the selected one are highlighted in a bright blue Remind that what you see in the monitor is affected by round off approximation made so as to 25 fit in the pixel grid An additional possibility is to directly verify the position of the shapes in the path from the popup menu select Dimension and Position You can also overlap shapes so as to be sure of the contact even if usually the number of mesh cells rises slightly In this case pay attention on where the additional mesh lines are placed due to overlap see also the next To Probe Further section for more details 3 You have shapes in contact but in different layers This situation may add a parasitic hidden capacitance to your structure only thick conductors only 3D working mode Solution and details are indicated in to probe Further 2 p 6 4 You have assigned the conductor resistivity to its embedding layer When setting the substrate parameters dielectric permittivity and conductivity refer to the dielectric layer and NOT to the conductors or the dielectric br
205. to try with Ny 1 and then raise Ny in order to see how results are affected There exists always a value after which no improvement is obtained If slicing is used where a quasi planar but thick conductor touches a via in order to allow for the correct modeling of current vertical bending generally Ny non uniform should be used as uniform Ny may result in a too large number To Probe Further 1 setting top and bottom wall properties EM3DS uses the modes of the enclosing rectangular waveguide in order to analyze the user defined structure Setting the top or bottom wall as infinite waveguide means that the enclosing waveguide is infinitely long in the upper or lower direction its modes being terminated over their characteristic impedance The user can select how the waveguide is filled This way a lossy ground could e g simulated by setting the bottom wall to material Infinite waveguide and by specifying the filling dielectric having a bulk conductivity 3 10 S m see figure below The infinite waveguide may also be used so as to simulate an open environment provided that the rectangular waveguide is large enough to avoid direct interaction with lateral walls and to allow over cut off modes that could model power leaking in the vertical y direction In this case the top layer could be simply air Layer 1 p 7 A Modes see a lossy ground Layer 2 g Lossy material The Approx Open option allows to terminate each wav
206. tors in layers with even index HAA aa aad Impressed field Fig 72 vertical excitation by via port 64 14t q Impressed field Fig 73 Via port obtained by applying a via excitation to a via conductor Note Ports cannot be attached to Perfect Magnetic Conductors PMC the E field orthogonal to PMC is zero Ports can be selected edited and deleted by mouse popup menu XXVI Post Processing Differential ports EM3DS handles differential ports in a post processing phase in order to create differential ports first add standard edge or via ports perform the simulation then access the Differential Ports dialog either from the main menu Tools or the dedicated button in the toolbar or the icon in the Data Browser Zo EM3DS Electromagnetic 3D Solver Editor General Draw Edit tools Post Processing Differential ports System Port Number User Port Number Hint This form allows you to 1 remap your port numbering 2 define push push or even excitations just use the same index for two or more even ports 3 define push pull or differential excitations use same index but a ar a a T AEE j sign minus of the pull port lt gt Data Browser f m x i At the end a new data file is created and linked to the project STS EJ Now Editing layer 1 air dh Parameters dh 2D Graphs dh 6 3D Graphs do amp Editor 3D Views fl a Circuits Tools Special Materials Mis _ Symme
207. transmission line has 50 Ohm both as source and as load impedance unless you double click over the ports of your project and you specify different normalization impedances Note that the TDR option can be applied also when displaying current field distributions any possible plot with the exception of contour plots and that time animation showing a transient can be generated even though this procedure is quite slow However when looking at the TDR in current distribution remind some assumptions 1 the source impedance is always 0 Y parameters are used in this calculation so that if a wave reaches the source it is reflected back completely 2 The load impedance is by default 0 but it can be changed to the port impedance value much like is done for the aforementioned charts Finally when creating time domain animations of the current distributions remind to select in the proper panel set fixed range when this is not done the plot is automatically adjusted to show variations in currents any frame in the time animation would have a different scaling resulting in a useless animation XXXV Post Processing displaying volume current distributions in surface plots At the end of processing by clicking over the View 3D graph menu Show 3D Plot of the currents button or double clicking over data browser Current density a window with the current distribution within the conductor dielectric brick volume is displayed Currents are displayed laye
208. trics Start Frequency GHz e Stop Frequency GHz 4000 2o o W Invoke automatically SmartFlT Num modes direct M6 Suggestion Num modes 2 direct A6 no suggestion no suggestion Default Output Touchstone File no extension is indicated W Always use suggested values Suppress wideband Mesh W Save EM computation hoo limit num modes W Automatic Deembed k Asymptotic approximation Help F1 J 2 50 simulation Invoked modes direction 3 minimum suggest 2 direction 3 A Cache Asym Info Fig 51 Selecting the number of modes In any case a remainder of this danger appears in the Event window At this point everything is ready Then close the window and try again with the Go button Calculation starts It takes something more than the enclosed example HISSwitchOn ems in the MEMS gallery This is due to the mesh that has not been optimized For any shape you can select from the popup menu the mesh options Tips and tricks about mesh as well as the meaning of the parameters are described before in the manual and we recommend to read those sections carefully as very high efficiency and accuracy may be obtained by some practice The first frequency point requires substantially more time than the others as the asymptotic estimator is invoked starting from the second point Asymptotic estimation is available for refining analysis by adding frequency points if neither the structure nor th
209. trix char Y TSComplexMatrix NumPorts integer frequency double autoExtension boolean Creates a new Touchstone file or append results to an existing Touchstone file named Filename If AlreadyOpen true then the file is supposed to have been created and the procedure appends the Y matrix to it otherwise a new file is create with all needed heading Y is a network either S Y Z matrix describing a NumPorts circuit If autoExtension is true the kind of matrix to be exported is defined by KindMatrix either s z y and string FileName should not include extension Otherwise autoExtension false implies that FileName also includes the extension e g filename is myTouchstone s2p for a 2 port S parameter Function GetVariableList tstringList 96 Creates a stringList indicating all existing variables in a given project For example Program TestStringList var s TstringList l integer Begin s GetVariableList For 1 0 to pred s count do MessageDlg Variable intToStr i s strings i mtInformation mbok 0 End This example recovers the list of variables in s then looks through s and issues a message type information with a button OK and no help Function ParseExpression s string extended This function evaluates the numeric value of an expression s The expression may involve variables defined in the EM3DS project For example if the variable list is defined a variable x you can pass as s the argument sin
210. try Wizard Z Batch Scheduler dip Differential ports rail Ext Data Files ot Mode rotate data source Current EM Simulation v Close Help Current EM Simulation Y Layer 1 IN Layer 2 lt ill gt Fig 74 Differential ports form Using this post processor is straightforward and it can process any network data including those imported externally and appearing in the Ext Data File folder Hence the first step is to select the desired Data Source If the source is the Current EM Simulation be sure to select De Embedded if you want to work on calibrated data At this point the table appearing allows to remap port numbering define push push even excitations and define push pull odd excitations In order to remap port numbering just insert in the User Port Number part the desired port number If two or more ports have the same index and same sign they are shorted together push push configuration namely in circuit terms they have same voltage 65 If two groups have same index but different sign they are connected in differential or push push configuration basically it is imposed that current flowing into the group with sign is the same exiting from the group with sign In the example above the result will be a 2 port where new port 1 will be the one differential having P2 as reference for P1 and by the same token new port 2 is the one having P4 as reference for P3
211. ts role only depending on the geometry It is somehow a context definition In the 3D mode volume currents are used to define the conductors the dielectric bricks and the active regions On the other hand in 2 5D mode the distinction between two class of conductors is assumed The first is the one of normal thin planar conductors and the second is that of the via thick conductors Normal thin conductors may only be placed in layers having odd index that will be so assumed to be infinitely thin for all purposes Actually the user will define the thickness also for those layers such a thickness will only be used for the correct evaluation of the conductor losses Via conductors and substrates on the other hand may only be place in layers having even index These conductors are defined by surface currents Jx and Jz and via conductors by vertical volume currents Jy We will see at the end of the section what to do in order to create the 2 5D example The 2 5D mode is much faster and easier to use especially at relatively low frequencies In order to set the 3D mode just go in the menu Settings and deselect the item 2 5D mode This item will be also accessible from the Project Data Window see next step Immediately any 3D view is updated according to the new selection any shape has the thickness of its host layer The lower status bar on the right side indicates that the current mode is 3D mode 4 The next step is to sp
212. ty or the acoustic velocity the acoustic impedance is automatically updated and vice versa Cells of the table may be resized by dragging the mouse over the separation lines The material properties may be saved as text file indicated with extension amt acoustic material model Any allocated table will be reopened automatically when reopening the project provided that the corresponding amt file is in the same directory of the project You can add also some line of comments that will be saved into the amt file EM3DS will exploit the acoustic analysis to create a special material in particular a special dielectric having the dispersive lossy and resonant behaviour due to the piezoelectric phenomena In order to do that select a name for this material Material name and then click over the Create Reference to Material button two variables one for the permittivity and one for the tand will be created as displayed in a dialog box In the electromagnetic simulator you can use these variable to define permittivity and tand of the piezoelectric film that you can place e g by defining a dielectric brick same variables are also available for definition of the layers in the substrate When you run the em simulation at each frequency em3ds performs a preliminary acoustic analysis and assigns the necessary electrical parameters to the em model It is also possible to perform an additional stand alone circuit analysis of the BAW FBAR this calls
213. u need to define at least one mesh cell between the reference plane and the ports to have reliable calibrated results If this is not the case the quality of de embedding may be poor Event Hint as a rule of thumb strictly valid for microstrips in order to get reliable results the reference plane should be placed at a distance greater than the substrate thickness check the XX Hand Side plane If a too short reference plane when analyzing the standard structure coupling via high order modes may happens between ports This way the calibration quality may be poor Event Remark you have placed your shape in a highly conductive layer A common error is assigning the conductivity of a shape to its embedding layer This remark is only added with the purpose of bringing to your attention this possibility Message Dialog Verify the distance of the reference plane it is outside the conductor it has been automatically displaced Probably you have resized a conductor or simply misplaced the reference plane so that now it is defined out of the shape Hence EM3DS set this plane so as to fit in the shape Message Dialog The active file belongs to a previous version of EM3DS available results may be lost Continue When developing new versions MEM Research pays attention to backward compatibility Hence you can always open an old project with a new version However any saving operation will transform the older project to a new one From one vers
214. uated over one half of the port sections Combination of PMC and PEC simulations can be used to perform effectively simulations of 2N port symmetric devices by means of 2 simulations of N port devices Actually this line of reasoning is valid for more complex symmetries EM3DS can handle automatically symmetries over one plane as detailed in the next section VIII Combining PMC and PEC or even odd simulations the Symmetry Wizard The Symmetry Wizard is a useful post processing tool to recover the complete analysis of symmetric structures from the analysis of two half structures This can be employed e g to characterize couplers or multiport structures having a symmetry plane An example will clarify Consider e g the microstrip coupler below with 4 ports top view 20 Fig 17 Microstrip coupler One can actually create two substructures each one with 2 ports and half of the size of the original one The first one where the symmetry plane is replaced by the electric wall or PEC of the box see left figure and the second one where the symmetry plane is replaced by the perfect magnetic wall of t Fig 18 Two half structures one with electric wall PEC odd simulation and one with magnetic wall PMC even simulation The user has just to simulate separately the two structures then invoke the symmetry wizard In fact if Y and Y are 2 port network parameters for the even and odd mode simulations Yz
215. uickly the computational effort hence if thickness of a set of objects is believed to have a limited effect the best choice is to neglect it If more in general thickness is not believed to be important for any of the elements of the geometry but vias the best choice is to switch to the 2 5D mode Click now over layer 2 and edit the layer parameters by setting the relative permittivity to 1 and the layer thickness to 1 35 um Layer 2 contains the bridge anchors Hence add one further layer after layer 2 by selecting add New Layer Bottom button Specify the relative permittivity to be 7 6 and the thickness 0 15 um It is the layer that will model the Silicon Nitride passivation By this choice the silicon nitride is assumed to cover and embed the entire lower electrode this is not necessary in EM3DS as you can also enter dielectric discontinuities but our choice simplifies the structure drawing Whenever you want to specify a silicon nitride brick to exist only over a portion of the structure leave the relative permittivity of the current layer to 1 and when entering conductors you will have to enter a dielectric brick having 7 6 relative permittivity in layer 3 Add one more layer having relative permittivity 7 6 and the thickness 0 8 um this is the lower electrode layer and we assuming that it will be embedded in silicon nitride namely spaces besides conductors are filled by silicon nitride 38 Edit tools Post Processing a
216. ult or 3D Data Browser in its root shows which layer is being edited if the user has assigned a name label to such a layer Fig 4 EM3DS 3D Views with perspective and rendering Many advanced features like zoom in zoom out or internal view of closed structures are allowed Thus the user may carefully inspect and or correct the design before starting simulation In the same manner this mode is fully real time updated when changes in the design occur In this same view you can see current densities plotted as pseudo colors or as vectors Windows may easily be removed or accessed by the Data Browser The Data Browser is a tree like structure to facilitate the access of multiple graphs where all results are contained and to simplify the manipulation of external data files e g provided by a network analyzer or by some previous simulation Other than through the Data Browser these windows can easily be accessed through the View drop down menu or through buttons on the toolbar Every accessible toolbar button is duplicated within the main menu A short Hint is provided upon mouse being pointed to the buttons All buttons are grouped in categories General Draw Edit Post Processing and are accessed by selecting items in the upper panel Pressing F invokes a context help Every window has its context help detailing the available functions Every window has its context help detailing the available functions Moreover nearly everywhere by ri
217. very different along the 3 dimensions in order to see details it may be useful to exaggerate magnification along one or more directions selectively This may be done by clicking over the Set Magnification Factor s item in the popup menu and selecting a selective zoom along one direction Fig 101 3D View with rendering 100 XLIV Project Description EM3DS provides a window where notes about the project may be written and displayed an RTF file indicated as DES is created automatically and reopened along with the project This file may be modified and saved independently XLV Translators importing and exporting DXF and GDSII files EM3DS has also some ability in translating its native files EMS into other popular formats It is possible to import Autocad DXF files Calma GDSII files and Windows Bitmap BMP files If the user selects to import DXF or GDSII file the layer list on left hand side reports the list of layer found in the file and for each layer in which layer of EM3DS the objects will be imported On the right hand side a list of commands ignored by the filter is shown DXF Translator Layer List Ignored Commands E nities um W Discard existing objects i Metric W Skip completely overlapped items Help F1 ig 10 2 DXF Import window In the lower dialog list you can change the layer of EM3DS where the highlighted item of the Layer list will be imported Skip completely overlapping items if selected requi
218. w Legend You can drag and drop by mouse the legend across the image In copy and paste operations legend will not appear Instead you can copy and past directly legend H 3D View Rendering 1 Sa Excitation General Animation Vector Layers Visible Layers Me Mu Mea Plot Mode rotate Fig 91 Contour Plot of the volume current distribution over the 3D structure with rendering including a top sense later The same kind of graph is available directly over the 3D views with rendering of the structure In order to show currents just select Show Currents from the popup menu of the 3D view If a sense layer was added the quantity displayed in that layer is the E Field Distribution Also there will be a legend for E field 1f a sense layer is applied or for currents Objects in each layer can be selectively hidden this is specially useful when e g the sense layer hides the other objects The sense layer is always layerl 84 As the drawing is a quite lengthy process by default only currents over the upper surfaces are shown However by selecting Display Setup Panel a lower panel is shown where possibly deselect Show only on up Surf Additionally the currents being displayed its frequency and other parameters may be modified Finally current distribution may be animated Fig 92 Contour Plot of the volume current distribution over the 3D structure with rendering Additionally vector currents may also be displaye
219. with the internal solver and how are treated modes below cut off the default value is 3 and should not be changed as this is most accurate for general calculation it can be raised to 6 or 9 for some kind of specific waveguide computations or for the calculation of the far field however increasing this value will deteriorate accuracy if long vias or very thick structures in 3D mode are used For this reason the entered value is not stored and after re starting EM3DS it will reload the default value Priority of the process It allows to select the priority in your OS of the EM3DS process The priority is effective only when you click set priority The priority will be automatically settled only if you select the checkbox Remember the priority 112 L EM3DS Electromagnetic 3D Solver j ction Tools Window Help E pa Ta 4 EM3DS loaded D DATA AWR COM EM_Socket MEMResearch Source EM3DS 2010 example pulseresp EMS Version 11 0 0 Sac 43D View General Draw Edit tools Post Processing Tutorials BEA ox P 4 Preferences j X C Mag Editor Computation Mesh M General Polygons r Slanting Rectangles P Uniform Mesh MV Uniform Mesh Uniform Mesh IV Mesh Border x Mesh Border x IV Mesh Border x MV Mesh Border z Mesh Border z M Mesh Border z m Spiral Ring IV Uniform Mesh Uniform Mesh IV Mesh Border x M Mesh Border x r 7 4 Data Browser OVX IV Mesh Border z MV Mesh Border z
220. xpression for instance sin 3 5 and is fully evaluated calculated by EM3DS thus facilitating the overall process and avoiding using calculators Unlike some other commercially available tools EM3DS does not pose any requirement on the grid The only event when grid is desirable and in fact EM3DS can make use of it is during the drawing where it offers additional flexibility As stated above EM3DS comes integrated with several tools aimed to ease interfacing with other CAE tools As to the pre processing step filters allowing importing GDSII and DXF as well as general bitmaps are available The post processor includes a Spice Model Extractor a simple Linear Circuit Simulator tools for saving animations GIF AVI link to AVI files via multimedia documents exporting graphs plots Smith Charts data files Touchstone to see the interaction between a user defined magneto static field and RF currents flowing across an object etc Nonetheless for MEM Research it is imperative to look for partnerships in order to better exploiting the EM3DS power This is why in the past EM3DS 5 was also fully integrated as Electromagnetic Module in the multi physic package by Corning Intellisense Intellisuite Currently EM3DS is companion of CoventorWare by Coventor leading company in the MEMS software development EM3DS was carefully selected by Coventor thanks to its remarkable achievements By the same token EM3DS has now the ability to be
221. xy and get its value Procedure SetVariableToValue variable string value double Set the variable variable to the numeric value value If variable is not in the variable list a new variable is created Variable MainEM3DSMenu TMainMenu Such a global variable is related to the main EM3DS menu so that you can add items or change the existing ones For example Program testmMenu creates a new menu in the EM3DS Var mi tmenultem m tmainmenu procedure myMenuClick sender tobject event when clicking in the new meny begin Analyze end begin Main program mi tmenuitem create mainEM3DSmenu create a new item mi caption My Analyze mi onclick myMenuCLick link to the event mi visible true shows mainEM3DSmenu items add m1i adds to the main list end In this case a new item in the menu of EM3DS the main one appearing with the editor has a new item My Analyze When clicked an analysis is started NOTE when there are events consider that if you discard the script the additional menu remains but the event is no longer linked to a located procedure Hence there will be an Access Violation error To avoid this problem modifications of the main EM3DS should be done always in Global Scripts 97 By the same token it is easy to create your own form for example Program TestFormAndButton Procedure MyOnClick Sender TObject Begin MessageDlg Hello mtinformation mbok 0 End
222. y applying a staircase approximation It is possible that the number of intervals added by the automated mesh be not the best choice so the user should try by changing the size of the mesh cells in the Mesh Options dialog box in order to get a better trade off between accuracy and simulation time see previous section The experienced user gets very accurate results with a low computational effort See figures Raw ineffective mesh Better mesh eee 7 ere ee Bees eee eee z mfe z G ere NG a ee t pam ieee Fig 29 Mesh polygons in both cases mesh is coarse but the right example would provide sound results Slanting narrow lines are probably where the currently used algorithm finds the worse difficulties currently the algorithm is being updated in order to automatically perform the steps indicated in the following l 3D View co Vie ENF A ae CHIE LL SAAS tS View mode rotate M Draw Axes tee Keep Ratio PF Show WR Walls W Real Time Refresh SILLA Fig 30 Slanting line where the automatic mesh algorithm is unable to provide a useful mesh continuity over the structure is violated If cells are not surrounded by other cells conductor may be not connected as shown in fig 30 In fact there is not continuous current flow along the line By suitably changing the mesh cell size of the polygon one obtains what shown in figure 31 Fig 31 Mesh polygons By changing the
223. y the Fit to Data check box limits are automatically sized Set the trace properties for the currently selected trace by clicking over Trace Properties Double click over the trace color in order to set the trace color Select the desired marker its size in points its border color Marker color and its filling color pn wW ll i 7 Trace Properties JOf x Trac Color Thickness Pts 2 Style Sold Mame s21 EM3DS Markers Data Marker Downtriangl If Show Marker Marker Color Fill Color Marker Size Cancel Help F1 Fig 81 Trace Properties 73 Set the plot area properties by clicking over Plot options or by double clicking in the plot area x steps and y steps are the number of horizontal and vertical grids respectively grids are only displayed if the Show x grid and or Show y grid boxes are selected ee Plot Setup steps f M Show x grid y format Horiz Margin 5 p steps E M Show y grid v Format HHHHHO H Vert Margin E background Legend Distance Caption Frame C horiz pt fe B Horizontal Axis Frequency GHz M Show Legend l wert pt E Vertical Asis i aff Font Cancel Apply Help Fig 82 Plot Options Background and Frame let you specify respectively the area and frame color Legend Distance is the distance from the upper right corner where the legend if any is displayed Horiz Margin and Vert Margin is distance
224. yer 1 for drawing For example in a microstrip circuit layer 1 could be the path layout layer while layer 2 is the substrate one where via conductors could be placed The layer immediately above layer 1 layer 0 cannot be accessed for conductors placing However this layer is the only one that could assume thickness O it is equivalent to removing that layer It is exactly why we have 3 layers visually presented and not 2 The top and bottom walls may assume either perfect conductor PEC namely zero E tangential field magnetic conductor PMC namely zero H tangential field absorbing boundaries or replaced with semi infinite waveguides filled by certain materials You can also modify two of the four side walls of the enclosure to be PMC or symmetry plane refer to the specific section about PMC an symmetry planes By traversing the mouse over cross section schematic the Data About panel displays the main properties of the tipped layer Left mouse click will provide access to and modify the properties of the selected layer You can also click in layer list A window similar to the one shown in figure 9 comes into view A few additional considerations should be kept in mind according the selected working mode either 2 5D or 3D The working mode is either selected from the main menu Settings see figure below or from the Project Data window i eciromagnetic J0 solver File Edit view BEd Action Tools Window Help Box di
225. ylIndexExists to recover the position in the list of a frequency f Function GetCurrent Y CAlibratedMatrix indexOfFreq integer CalibrateToPort boolean var success boolean TSComplex Matrix Provides the calibrated Admittance matrix for the calculated structure at the frequency in position indexOfFreg in the frequency list Use function FrequencylIndexExists to recover the position in the list of a frequency f If CalibrateToPort is false results are at the specified calibration plane while if true results are calibrated at the port plane XLII Printing Since version 12 a set of utilities to print out in a standard printer any chart graphic or image in EM3DS is made available For example from the menu File gt Print or from the Print popup menu in any chart or graphic you access a Print Preview form a Print Preview JAIAK d b mi Fig 99 Print Preview Form From this form clicking on the buttons shown in the toolbar you can change the page setup setup the printer show hide margins print zoom reduce the image show in Black white or Color browse between pages and save as TIFF By moving the mouse across the buttons it is possible to see a hint about the function of each individual button XLII 3D View The structure being drawn is displayed in its 3D view The view can be handled by right clicking over the figure by selecting zoom move or some other action and dragging the mouse over the image Boundary
226. yze and predict scaling and topological effects The same considerations apply to the modeling of SiGe devices The differential gate to drain feed back capacitance C has also to be considered in the normal saturation operation of linear microwave FETs it is nearly independent of the biasing point reducing to the gate to drain interelectrode capacitance hence no further modeling is needed Whenever the Operating point does not completely satisfy the saturation hypothesis an additional capacitance between gate and drain electrodes has to be added at the network level With a view to model velocity saturation of the carriers the active channel is divided in two regions a high conductivity area between gate and source and a lower conductivity region saturation region between gate and drain as shown in figure above for the HEMT The highly conducting region is responsible for the intrinsic gate to source resistance R Its resistivity is linked to the latter parameter as follows _ RhW 3 lotl Pr where is the distance between gate electrode and source cap W the device width and A is the depth of the undepleted part of the channel for MESFETs and the 2DEG thickness for HEMTs The saturated low conductivity part of the channel is responsible for the differential output resistance of the FET RAW o 4 loa l 4 being the distance between gate electrode and drain cap Values for p and pp may also be obtained directly from t
227. zation oh 2D Graphs S i 3D Graphs a amp Editor 3D Views Run Batch Simulation a 7 Circuits Help Cancel i Efe Tools S pecial blat Symmetry W ws Batch Sche Fig 113 batch planner scheduler When you click Add File you are prompted to select an EMS file the project will be opened in order to check if it is a complete and valid file Hence the name of the selected file appears in the list of the batch planner Repeat the procedure as many times you need to create a queue namely a complete list You can also select a task from the list and remove it by pressing DEL key or button Delete File Check Run Optimization if actually your projects involve any parametric optimization Otherwise leave this item unselected Hence press Run Batch Simulation Any file is opened simulated and saved automatically while a summary of events with timing is reported in the summary list below L Accessing and using EM3DS from AWR Microwave Office EM3DS works also as server for AWR Microwave Office 6 or later This means that AWR s customers are able to see EM3DS as an electromagnetic engine still using Microwave Office editor and post processing capabilities This capability is devoted to the seamlessly transfer of geometry and parameters between the AWR suite and EM3DS To date this feature has been developed mostly in one direction any structure designed in Microwave Office may be seen and simulated directly into EM3DS but

EM3DS Manual

Contents

Download Pdf Manuals

Related Search

Related Contents