S-parameter Simulation_BB2

- Coupling noise has become an important issue which must be modeled appropriately.Advanced Design Systemis the world's leading electronic design automation software for RF, microwave, and high speed digital applications.This presentation demonstrate about 1.How to model PCB traces,vias,etc using Agilent ADS.2.How to use ADS-CADENCE utility 3.How to use ADS momentum to simulate network parameterHow to use ADS momentum to simulate and analyze same layer crosstalk and interlayer crosstalk in frequency domain

IntroductionCreating/importing PCB artwork

Ads-Cadence Link

Momentum _ Loss Analysis;

MOM vs FEM

Creating/Modifying substrate, stack-ups and layers.

Placing and defining ports, Defining mesh.

S-parameter data display

Near-End& Far-End Crosstalk Measurement.

Interlayer Crosstalk Between Dual Stripline

AgendaAdvanced Design SystemAdvanced Design System is a electronic design automation tool for RF, microwave, and high speed digital applications.3D EM Simulation tool from Agilent Technologiesin-built transmission line models, microwave models, substrate models etc.option to modify the above models based on our design requirement.has two key EM Tools,viz, ADS layout and ADS Schematic.

3Starting a Design in ADSStartAll ProgramsAdvanced Design System 2009 Update 1 Advanced Design System 2009 Update 1

Creating/importing PCB artwork in ADS

Draw/Create within ADS layout.

Schematic-to-Layout transformation.

Import (DXF, ODB++, etc.)

Export from Cadence and import in ADS layout.

ADS LayoutOpen ADS layoutChoose your Tline model, and edit /update the model based on your requirementDefine substrate, layer.

6ADS-Cadence LinkSelective transfer of nets (traces, power/gnd planes) cookie cutter featureSubstrate stack-upAutomatic port generation

To enable the Export To ADS option, go to your ADS installation Directory(C:\ADS2009U1\ial\scripts) and Replay the eemLocalConfig.scr

Once you done the above procedure, just restart the allegro, then we will be able to see the new menu (Export To ADS)in our cadence tool.

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artwork creation/import process is done, now we are ready to go for MOMENTUM SIMULATION.Momentum _ Loss AnalysisThis system has 360 high speed differential signals running at 3.75 GHZ frequencies(7.5 Gbps) and these signals looped back to its motherboard through Amphenols crossbow Connector.Loss measurements are performed on the longest and shortest high speed data channels. Task is to find out the maximum /minimum allowable track length of the high speed data signals.

There are 5 process in MOM method *Substrate*Port*Mesh,Edgh Mesh*Planar EM Solve*Data Display

MOM vs FEMTwo types of simulatorMomentum(Method of moments)FEM(Finite Element Method)

Momentum enables you to:Simulate when a circuit model range is exceeded or the model does not exist Identify parasitic coupling between components Go beyond simple analysis and verification to design automation of circuit performance Visualize current flow and 3-dimensional displays of far-field radiation

Longest & Shortest Channel

Substrate

Momentum>Substrate>Create/Modify

*Substrate*Port*Mesh,Edgh Mesh*Planar EM Solve*Data DisplayPortMomentum>Port EditorMake sure all the port are having reference(GND)port assigned correctly. 5 types of ports:single Internal Differential Common mode Ground reference

*Substrate*Port*Mesh,Edgh Mesh*Planar EM Solve*Data DisplayMesh,Edge MeshMomentum>Mesh>setupA mesh is a grid-like pattern of triangles and rectangles, and each triangle or rectangle is a cell.The mesh is applied to the circuit in order to compute the current within each cell and identify any coupling effects in the circuit during simulation.Edge Mesh to add a relatively dense mesh along the edges of objectsSince most current flows along the edges of objects, the edge mesh can improve the accuracy and speed of a simulation

*Substrate*Port*Mesh,Edgh Mesh*Planar EM Solve*Data Display

S-parameter SimMomentum > Simulation > S-parameters*Substrate*Port*Mesh,Edgh Mesh*Planar EM Solve*Data DisplayData Display

*Substrate*Port*Mesh,Edgh Mesh*Planar EM Solve*Data DisplayLoss ResultsDo the same for Shortest pair

Do the same for Mother board RX,TX pair

Combine all of them in ADS Co-Simulation(ADS Schematic)

Run the S-parameter simulation again.

View the Final Channel Loss Results

Near-End& Far-End Crosstalk Measurement

Far-End Crosstalk Measurement (S41)

Near-End Crosstalk Measurement (S31)

Interlayer Crosstalk Between Dual Stripline

For the analysis High speed pairs from T06 & T05 layers are considered for analysis

The dielectric spacing between these dual stripline layer is 7.9mil

In the below picture the pink traces are on T05 traces and orange traces are on T06 trace. The traces on T06 are the aggressor nets.