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Where To Find This Example

AWR Version 14

Select Help > Open Examples... from the menus and type either the example name listed above or one of the keywords below.

Or in Version 14 or higher you can open the project directly from this page using this button. Make sure to select the Enable Guided Help before clicking this button.

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AWR Version 13

This example was renamed since the previous version. Please see Previous Example Page for the version 13 page.

Design Notes

Axiem EM Solver PCB VIA Pre-Processing

This project demonstrates the capabilities of AXIEM rules based geometry simplification. In this case a sample 4 layers PCB  PCB is shown and it is based on the generic AWR_Module process.

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Vias are also added to the layout view in various distributions around the signal line and throughout the plane acting as ground. To include a shape in EM Extraction, right-click select the shape in the layout view, and then select Shape Properties > Layout Tab.   Then check the option to enable EM Extraction.    Refer to AWR Documentation for more details on extraction. 

Geometry Simplification and Extraction to Axiem

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The extract block references a STACKUP named “Thin"Thin_Metal” Metal" that is located in the Global Definitions.    Double click on this STACKUP and go to the Rules tab to see the geometry simplification rules.    There are comments above each rule explaining what they do.      

Viewing Simplified Geometry

After you have created the EM document there are several ways to see the simplified geometry.    You can right click on the EM document and select Preview Geometry to see a new view showing the processed geometry.    You can also mesh the structure to see how the mesh will look for the structure.    Open a 3D view of the structure (with the 2D layout active, select View EM 3D Layout) and then click the Show 3D Mesh button from the toolbars.   

You can see the effect each simplification rule will have on the size of problem to solve.   The easiest way to do this is to comment out individual rules in the global STACKUP element, then right click on the EXTRACT block in the schematic and select Add Extraction.   Finally, mesh the newly updated EM structure.    After meshing is complete double click on the Information node under the EM structure in the project tree to see the listing of the number of unknowns.    

The approximate problem size is listed below with the specific rules enabled:

            No Rules = 20,500

            After Via Pad Removal = 19,500

            After Via Merging = 5,250

            After Decimation = 2,500

As you can see the rules have made an order of magnitude reduction in the problem that must be solved.   The via merging rules will take some time to complete. The reduction in the problem size is well worth this upfront time.   

Simulating Results

The project includes a graph that shows the simulation results of the MCTRACE element from the schematic. Simulate with the Extract block enabled and disabled to view differences between the EM simulated results and circuit model results. The MCTRACE circuit model assumes an infinite ground plane without any ground return on its side. In the case of extraction to EM, the ground return from vias surrounding the MCTRACE is also modeled.

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