Calculating Trace Width and Pitch Using the Layer Stackup Wizard (HFSS 3D Layout)

From the Trace Computation Settings area of the Layer Stackup Wizard, you can configure and perform a trace width (or pitch) calculation.

Prerequisites:

• Use the View Pane to select a layer. The Selected Layer Name field displays the currently selected layer.
• Click Trace Cross Section to open the Trace Cross Section editor.
• Click the Frequency drop-down menu to select the frequency used for trace width calculations.

To calculate trace width or pitch:

1. Select the Synthesis tab.
2. Select the Single Ended Nets or Differential Nets tab.
3. Use the drop-down menus to select the required impedance or differential impedance (in ohms), and as reference layers.
4. If you are using the Differential Nets tab, select eitherFix trace width at or Fix trace pitch at and enter a value.
   Important:

   By default, Fix Trace Pitch is selected. Selecting Fix Trace Width changes the calculator so that it computes pitch instead of width.

   

5. If you wish to define coplane wave reference planes, select Define CPW ref. planes (edge-to-edge) to enable additional options.
   • You may select Left plane spacing, Right plane spacing, or both.
   • For W-element export, selecting Left plane spacing means that aggressors may only be added to the right of a victim trace; any traces to the left are removed. Selecting Right plane spacing means that aggressors may only be added to the left of a victim trace; any traces to the right are removed.
6. To perform the calculation, click Compute width. The green progress bar shows the calculation's progress. When the calculation is complete, the Approx width area updates to show the calculated result.

   

7. Use the slider above the progress bar to update trace width and the required Zdiff value.

   

8. To perform the calculation, click Compute width.
9. The Approx width area updates to show the result.



10. Use the slider above the green bar to update trace width and the required Zdiff value.