EM Simulators for PCB Design Verification

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Microwave Office | Visual System Simulator | Analog Office | AXIEM | Analyst

Using 3D Planar and Full 3D EM Simulators for Design Verification


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What is Design Verification?

Often the (spatially limited) RF functions of a product PCB are designed assuming an ideal environment regarding chassis shape, ground planes, digital control lines, bias etc.

The initial RF real estate area on the board may change, the physical properties of the board may change, more or less substantial tweaks may take place when the RF section is laid out in the manufacturing tool

For these reasons it is often a good idea to perform a verification simulation using the actual layout data from the manufacturing tool before prototyping

If OK

AWR EM model


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Outline of the Flow

Simple single-layer layout data can be exported as dxf from the mfg tool

Complex multilayer layout data can be exported as ODB++ If ODB++ export is not available, Gerber data can be used dxf can directly be imported into AWR ODB++ and Gerber data is processed using a conversion software

Netex-G for AWR from ACS (Artwork Conversion Software) Direct AWR export option is available from Cadence Allegro and

Zuken CR8000

Mfg tool (MG,

Cadence, Zuken, PADS...)

Netex-G AWR

ODB++, Gerber 3Di

AXIEM Analyst


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Flow Demo

Open Netex-G for AWR. If the data is available as ODB++, just choose File > Import ODB++

If the data is available as Gerber (demo), have a document available for the layer file names and drill file format

In EM simulation we are only interested in metallizations and vias


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Flow Demo Preparations

A number of general settings can be done under Preferences

Recommendation: use very short directory names


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Flow Demo Preparations

The tool eventually outputs a 3Di file. The output file directory was set under preferences, the output file name is set under Output


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Flow Demo Stackup Definition

In Netex-G we populate the stackup as shown

Click to browse Gerber files


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Each layer can be previewed


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Metal and dielectric properties are set under Properties


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Flow Demo Drill Files

Drill file is set under Drills

Drill file needs first be converted into Gerber

Now you need to know the drill file format version


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Flow Demo Drill Files

Once drill file is translated into Gerber, browse the file and set top and bottom layer numbers (usually first and last)


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Flow Demo Choosing Extraction Area

Normally only a portion of the design is exported to MWO This is controlled under Extractions

You can either choose to extract an area, or a selection of nets with a given cutout region around them


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Flow Demo Choosing Extraction Area

Use the selection tool (rectangle, polygon) to choose the area You should see the vias now. If you dont, you have a problem with

the drill file.

When ready, Finish


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Flow Demo Extract

Then its time to Execute the extraction

This is what you want to see! You can exit the tool.


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Flow Demo Import of 3Di File into AWR

In AWR side, launch 3Di Import wizard Browse the file from your chosen output directory If your data was ODB++ with component info included, you can

choose to import such that the wizard creates a dummy schematic with connectivities defined as iNets

If you have only geometry, choose Layout only


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Flow Demo Import of 3Di File into AWR

You get the design in as schematic layout, with all drawing layers set The wizard also creates a STACKUP under Global definitions


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Flow Demo Cleaning the Design

It is a good idea to double-check the STACKUP and fix if necessary, before creating an EM doc

Normally there are also details in the design that are not necessary for the EM simulation, and can be removed

44k unknowns = OK, but removing floating pads and unconnected traces will reduce the unknowns by 50%


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Thank You!

Questions and test cases can be sent to

[email protected]

EM Simulators for PCB Design Verification

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