ADS - Sonnet Software
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1. Metal M1 o 3e7S m ADS cond 1 via ADS via 39 Metal M2 o 3e7S m ADS cond 2 substrate r 11 9 cond 5S m SONNET When to Use Sonnet Professional Analysis The use of electromagnetic analysis with Sonnet Professional is especially valuable in the following design situations When parasitic coupling is present Parasitic coupling is not always easy to predict without using electromagnetic analysis Even elements which are sufficiently far apart can suffer from parasitic coupling inductive or capacitive coupling resonance effects due to grounding and surface waves that might propagate at the substrate boundary under certain conditions Sonnet Professional analysis is based on the physical properties of your technology and will account for such physical effects When accurate circuit models are not available or circuit model parameters are out of range Model based circuit simulators are based on models for a specific application with limited parameter range For example only selected geometries substrate types and substrate parameters are available It is difficult to estimate the error induced by parameter extrapolation so using models outside their designed parameter range is not suitable for critical applications Whenever a layout feature cannot be described by a circuit model due to its geometry or technology the physics based analysis with Sonnet Professional will provide the answer An example for th2. 125 83 3 41 7 0 00 Current density at 15GHz is shown in the second picture In this case skin effect iod losses will dominate the spiral Q as the skin effect is much thinner than the metal 275 In addition current crowding is observed below where current tends to have a 250 maximum on the edges of the transmission lines Current crowding 225 occurs at higher frequencies where the self reactance of the transmission lines is 200 comparable to or greater than the conductive loss Note the high edge current that Sonnet conformal meshing shows very accurately This edge current must be modeled very accurately by any EM analysis tool in order to correctly assess the losses in the device that contribute to the Q 175 150 125 100 75 0 50 0 25 0 0 00 Back annotating results to ADS You can easily back annotate EM simulation results to ADS to use it in a model based simulation In the Sonnet plotting tool emGraph select the data set which you want to export then use Output gt S Y Z Parameter File from the menu This brings up a dialog where you can save model data in Touchstone S2P MDIF and other file formats That data can be used easily in ADS as black box data just like measurement results The Ebridge plug in also offers a menu item mport MDI Fto assist you in reading MDIF swept parameter results created by a swept parameter EM analysis in Sonnet into an ADS schematic SONNET
3. Tools gt Add Port command and click on the polygon edge where the feed line touches the box wall This adds a box wall port at that location with the positive terminal connected to the feed line and the negative terminal connected to the box ground Metalization Properties gdsii_example son xl Hetal Mixed Fill Type Conformal Sub Staircase ubsectionin Diagonal X Min SD oci Ww kd T xgeom 10 03 gdsii_example son pT File Edit View Tools Modify Circuit Analysis Project Window Help AA bh SONNET Add Reference Planes Optional To compensate for the additional length of the feed line a reference plane shift can be applied by using the Circuit gt Ref Planes Cal Length menu item A dialog will be displayed where you can enter a reference plane shift for each side of the box The offset value can be a fixed value or linked to a polygon vertex The value can be typed in or defined by a left button mouse click at the desired location If you need to define an internal port inside the box with no access to the box wall you can also use an auto grounded port which connects to ground automatically using a via which is added at run time and goes down through all layers until it touches the bottom of the box Auto grounded ports can be attached to a polygon edge at any location inside the box We strongly recommend to use box wall ports when you have lossy bulk layers A
4. identical to a discrete frequency analysis for Q factor values Requires Sonnet Version 10 or later T xgeom 10 03 Clickordra 1 9x 184 0 610 0 microns Pointer Ell Advanced Options conf spiral v10Oa son Ad xl Advanced Geometry Options Box Resonance Info Multi Frequency Caching v Q Factor Accuracy Force Analysis ABS Caching Level C None Stop Restart C Multi Sweep plus Stop Restart ABS Frequency Resolution Per Sweep Automatic 300 Frequencies Target C Manual o s GHz Additional Options p B Cancel Help Ell Analysis Setup conf spiral v10a son 321 xj Options Compute Current Density l Memory Save Analysis Control Adaptive Sweep ABS Start Stop GHz GHz 0 1 15 0 Speed Memory Cancel SONNET Help Plot Analysis Data Electromagnetic analysis with the example shown here will take 16 minutes and 59MB memory to simulate the complete frequency range full thick metal analysis on P4 2 5GHz with very fine geometry sampling of 2um at 600um box size Plot Equations When the EM simulation is done you can now use the new equation feature which plots results based on predefined or user defined equations Sonnet has already included equations to plot the series inductance of two port devices equation name inductance2 and the quality f
5. please contact Sonnet support for the details Box and cell size are set in the Circuit gt Box dialog If you change the box size and want to move your circuit you can do this easily by first doing Edit Select A lt Ctrl gt lt A gt and then moving the circuit with the mouse or use Modify Center to center it horizontally and or vertically in the analysis box RFIC SONNET prj layout source Layout 4 File Edit Select View Insert Options Tools Schematic Momentum Window Ebridge DesignGuide Help la k tva 9 5 Jr i d TLines Microstrip E m i e NN lu Tr ault 1 oe File Created sonnet layout_ source son To use ihla eromple wlih plengse make aure dhot 1h SOME T Por BEE Din 497 lot geq in vate 40 canti LL itis eontlafde etq 4l pr If qhis ts nnl E 1 He drothsalottr ih reqTerence r 1 ope HBend MEsTub itl noft e ES Tle For EN r Toe un SE 5 xj Ele Ede iew Anas Project Window Hein ISTE dea enomple sonz IBI xd d ETT amp Ee i a pe 5 es ag ais ia Je z e amp amp epp Eas TT XI xj SIZES x Y Top Metal Cell Size zn z o l Lack fi sslezs Hox Size 512 0 i517 l Lack Bottom Metal Hum Cells 256 256 Lock Set Box Size with Mouse Cell Size Calculator Current Unite Lassless Symmetry Estimate Memory Cancel micrans OK Apply Help vin rats ie RR ae z S J Cl
6. RFIC Layout Analysis Using Sonnet EM with Agilent EEsof EDA s Advanced Design S ystem ADS Sonnet Application Note SAN 202A RFIC SONNET prj layout source Layout 4 i B x File Edit Select View Insert Options Tools Schematic Momentum Window Ebridge DesignGuide Help S A tj cy Selected gt Geo Edit Preference File TLines Microstrip Launch xgeom efault Import Mdif Launch Sonnet EI Find Tranlated Files Launch Runwin ee ee eromple wlikh Sonne pie TEXTIL bd Joao Sonnet Info EINAT FBFI DBE DIR Tr gt ge Hn yatr San Hr Ai en t Trle contig de pr nh ilpkRr he TE RE E ee Eworg A is nod se r 1 op itl nof Pr Tle For Lh z SONNET EE Description of Sonnet Suites Professional Sonnet Suites Professional is an industry leading full wave 3D Planar Electromagnetic EM field simulation software based on the Method of Moment MoM technique which accounts for all coupling and radiation effects from DC to THz lt also takes full advantage of mathematically robust and reliable FFT formulation which avoids time consuming error prone numerical integration Both MoM and FFT combined gives Sonnet an added assurance that it will give outstanding accuracy every time on problems that have traditionally been difficult to solve Problems with high dielectric constant thin dielectric layers and or small dimensions with respect to the wavele
7. This application note is courtesy of Dr Ing Volker Muehlhaus of Muehlhaus Consulting amp Software GmbH www muehlhaus com NNET Sonnet Software I nc Phone 315 453 3096 Toll Free in North America 877 7SONNET Email info sonnetsoftware com Web www sonnetsoftware com United States Regional Sales Eastern US Sales Office 203 439 0815 Western US Sales Office 303 443 2646 J apan Sonnet Giken Co Ltd Phone 43 463 6663 Email info mail sonnetsoftware co jp Web www sonnetsoftware co jp Germany Muehlhaus Consulting amp Software GmbH Phone 49 2302 91438 0 Email info muehlhaus com Web www muehlhaus com 12
8. actor To plot these values bring up the result in the emGraph data display then use Equation gt Add equation curve from the emGraph menu Note You can also plot results of different equations on left and right axis at the same time or plot equation results as a function of a swept parameter Smith Plot Impedance ZU 50 0 gdsii example 11 Add Equation Curve Sonnet Software Inc Equation Phase Difference dB Difference Inductance2 nH Equation Details Inductancel nH pair of ports assuming a Pl model Cartesian Plot ZU 50 0 Left Axis Q Factor o gdsii example lt Right Axis Inductance2 nH El gdsii_example_2 Curve Label cut equalwidth3 2 Cancel Help NO o3 ese CO CaS 3 T 3 4 06 8 10 12 14 16 Sonnet Software Inc Frequency GHz View Current Density Amps Meter It is also interesting to observe the current P density as a function of frequency Calculating the current density adds 458 minimal EM simulation overhead but it is e very useful to gain insight into how a circuit works and what cell size is 375 appropriate 333 Current density at 0 1GHz is shown in the figure to the right Since skin effect at this low frequency is much thicker than the metal current is relatively evenly distributed across the width of the transmission lines and the conductive losses dominate the current spreading i effects 250 208
9. ches Easy to use data display for analysis results including R L C Q evaluation Equation capability for pre defined or customized calculation on simulated data All configuration and technology setup is menu dialog based no need to edit configuration text files Remote simulation capability Compatible with the LSF cluster and load balancing system Seamless integration with Cadence Virtuoso Agilent EEsof EDA s ADS AWR Microwave Office and Analog Office and Eagleware Elanix GENESYS design environments Sonnet Software Inc is a Cadence Connections partner SONNET 2 Introduction The Sonnet Professional electromagnetic analysis program offers a menu level integration into the ADS design environment This interface called Ebridge allows the RFIC designer to take layouts very easily from ADS to Sonnet for high precision EM analysis and back annotate results Material and technology information will be extracted from schematic MSUB blocks or from a project technology file Sonnet simulation del Substrate i made l x 1 from circuit Bm l simulation MM foptional preference file MEM technology ADS M Sonnet simulation E schematic results In this document we will study the data transfer and simulation setup of a layout only project with no circuit models We base our symmetrical inductor example on the following sample technology air sr 1
10. ick or drag to sole 1 0 512 0 842 0 rnicr nr Pointer SONNET 5 Subsection type For EM analysis of RFIC inductors Sonnet s new conformal meshing capability is very useful because it enables significant memory and simulation time reductions for curved and diagonal polygons Please refer to the Sonnet User s Guide for more information about conformal meshing You can enable conformal meshing per polygon but you can also do Edit gt Select All and then change all polygons at once Modify gt Metal properties Fill Type Add ports Once the EM Project geometry including vias is complete and material properties are defined the remaining step is to define ports In Sonnet different port types exist but the most common port type is the box wall port Box walls are well suited for inductor analysis because we can easily and accurately de embed the feed line up to the desired reference plane Calibration error for box wall ports in Sonnet have been shown to exhibit numerical noise errors than better than 100 dB down or more To define a box wall port you must extend each feed line to a box wall You can do so by adding a new polygon or by stretching an existing polygon One easy method to stretch use the Tools Reshape command and drag a window around the edge that you want to stretch Then use the Modify gt Snap to command to snap the edge to one of the box walls To define a box wall port use the
11. is could be a special inductor capacitor or transformer which is not included in the design kit Sonnet can be used to analyze those components on the fly or generate a full library of components models with trustworthy electrical results Sonnet Plug in for ADS Ebridge Sonnet offers a menu level integration into the ADS environment through the Ebridge plug in This is an add on from Sonnet Software which requires a license The Ebridge menu is loaded into ADS as described in the Sonnet Installation Manual in chapter Configuration Procedure for the Agilent Interface In this example we assume that the ADS variable SONNET EBRIDGE DIR sonnet is also defined in the ADS configuration file de cfg to specify a subdirectory sonnet within the ADS project directory where the Sonnet preference file and the Sonnet simulation models and results are located When activated the ebridge menu appears in both the ADS Schematic and Layout windows as illustrated below RFIC SONNET prj layout source Layout 4 E _ Oj x File Edit Select View Insert Options Tools Schematic Momentum Window Ebridge Designiuide Help Rep gt Geo Selected gt Geo Edit Preference File Launch xgeom efa ult Import Mdif Launch Sonnet Find Tranlated Files Launch Runwin nel ampla wlik 542 m METTI ihe varlanie Sonnet Info DIF NE PEE LE e ANS cantlqurat ten Tq Ebridge Menu within Agilent ADS SONNET 4 What is the Eb
12. ngth are handled especially well with Sonnet Sonnet continues to be an indispensable tool for designers involved in RF Microwave circuits such as distributed filters transitions Low Temperature Co fired Ceramics multi layer RF packages coplanar waveguides and antennas In addition Sonnet has proven successful in mm wave designs as well as in EMC and EMI analysis Sonnet Professional Key Benefits Accurately model passive components inductors capacitors resistors to determine values like RLC and Q factor Accurately model multi layer interconnects and via structures Generate a technology accurate electrical model for arbitrary layout shapes Quantify parasitic coupling between components interconnects and vias Include substrate induced effects like substrate loss and eddy currents Visualize the current flow in components interconnects and vias Sonnet Professional Key Features FFT based Method of Moments analysis for ultimate reliability and accuracy Easy to learn easy and efficient to use Only one high precision analysis engine no need to switch between solvers Patented Conformal Meshing strategy for very efficient high accuracy meshing of curved structures Finite thickness modelling including advanced N sheet model Dielectric bricks for truncated dielectric materials e g MIM capacitor Adaptive Band Synthesis for fast and reliable frequency sweeps with a minimum number of EM samples more efficient than traditional approa
13. ridge preference file In our example we use a layout translation with no reference to a circuit simulation schematic Thus we cannot get substrate and metal information from an MSUB 1 schematic element and need to get all physical material information from a preference file In our example we will use the preference file to define the metal types and their use for different layers the substrate materials and thickness stack up and also some simulation settings like frequency range and cell size EM simulation spatial sampling resolution In this document we will only give a brief description of the settings used A detailed description of Ebridge and the preference file entries can found in the Sonnet User s Manual 1 MSUB is just one example here Ebridge also supports many other substrate blocks To edit the preference file select the menu item Ebridge Edit Preference File Here is the file that we use for the technology in this example SIZE X CELL 2 n Se iieknese simulation cell size is EXT 100 2um ur o Name CUSTOM SUB CLAYER 2000 l 1 l 0 0 e CLAYER 2 349 0000 Oxide above M1 Level 0 CLAYER 1 Sid 0 0 Oxide at M1 CLAYER 2 3 9 0 0 Oxide between CLAYER 1 3 9 0 0 Oxide at M2 Level 2 CLAYER 2 3 9 0 0 Oxide_below_M2 Dielectric layers CLAYER 300 11 9 1 00 5 0 Substrate E from top to bottom Level 4 m i A SETUP METALIZATION LOSS Thick metal model 3e7S m 1 mic
14. ron 2 sheets MET Mi TMM 370000000 12 MET M2 TMM 370000000 12 ignore layer 37 Momentum Box metal types LAYER 37 IGNORE used by index MAP METALIZATION LAYERS starting with 0 ADS layer 1 to Sonnet level 2 material index 0 gt M1 ADS layer 2 to Sonnet level 4 material index 1 gt M2 LAYER 1 2 0 LAYER 2 4 BOUNDING BOX TO BOX BOTTOM LAYER 13 GND 1 drawing layers MAP VIA LAYERS mapping and metal ADS layer 39 to Sonnet level 3 material index 1 gt lossless LAYER 39 3 1 VIA type assignment SETUP REFERENCE PLANES lossless index 1 number of substrate heights to add to each side of circuit eee we use this to set the Sonnet box size ANALYSIS FREQUENCY SWEEP in GHz bounding box FREQS ABS_ENTRY 0 50 20 DC_FREQ AUTO via layer E mapping and metal type assignment analysis setup frequency range SONNET Definition for thick metal analysis In the preference file shown here thick metal types are defined Many RFIC technology components contain transmission lines and other adjacent metal traces with narrow gaps that are on the order of the metal thickness In these cases electromagnetic analysis with true thick metal analysis will provide more realistic simulation results For this reason our example is based on thick metal analysis For a discussion of thin metal vs thick metal please refer to
15. the Sonnet User s Guide Chapter 19 Thick Metal Create the Sonnet simulation model from ADS To create a Sonnet simulation model file from the current layout view select the menu item Rep gt Geo from the Ebridge menu This will create the Sonnet EM simulation model and show a message when the file was written successfully Now you can open the Sonnet EM simulation model file in the Sonnet project editor xgeom To do so select the menu item Launch xgeom from the Ebridge menu The EM simulation model is almost complete now except for the port configuration and a few advanced simulation settings Box and cell size The EM analysis cell size was taken from the preference file 2um in both directions and the box size was set automatically during data translation as the bounding box of all translated objects In our case we had included the ADS layer 13 bound and mapped it to the bottom of the analysis box in Sonnet It has no effect on EM simulation it only helps during data transfer to set the bounding box as desired because it is the biggest layout object For good results the size of the analysis box and the cell size must be configured with care The cell size determines the spatial sampling resolution for the EM analysis engine so this is the key to high precision results The box size must be large enough to avoid coupling between the circuit and the side walls If you have any questions on these issues
16. uto grounded ports may give invalid results with very lossy substrates xgeom 10 03 gdsii_example son File Edit View Tools Modify Circuit Analysis Project Window Help Ja ST ENA Er ese i Reference 0 th ini x l amp x XS SI Status SOO Yr Left None C QR Right None X MOT AA Top None ZZ Fixed plane length of 228 microns 23 p 4 Bottom Box Wall Reference Plane y xd f Linked Link Plane to Point of Polygon K i M ooo Yy Fixed Specify Length IS 228 0 micro Yy C None De embed Port Discontinuity Only Y y Y M Use fixed cal length o 0 micro T y Apply Cancel Help E ANT NN m Ah L ier aj pE ol Click or drag to select objects drag to move them 2 4K 394 0 12 0 microns Pointer SONNET Run analysis to generate S parameters and L Q plots After setting up the simulation model a typical thick metal circular spiral inductor might look like Analysis Setup To set up analysis use Analysis Setup from the Sonnet xgeom menu In most cases an Adaptive Band Synthesis ABS sweep over a wide frequency range will be the best choice e g 0 1 15GHz This typically takes five or six EM simulated frequency points to generate fine data output at approximately 300 frequency points in the desired range 0 1 15GHz Please don t forget to enable the advanced solver setting Q factor accuracy to ensure that ABS results are visually
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