What is the recommended wave port PEC cap thickness in HFSS?

 Ansys does not have a formal best recommendation for the thickness of the PEC cap since a wide range of thin values would work fine. When using the Automatic PEC cap creation for the wave port option, a suggested value is given for the PEC cap thickness. This value corresponds to the port diagonal divided by 10. You can change this value, but there are considerations:

1- A very thick backing object can interact with other fields inside the problem domain in an undesired way.

2- A very thin backing object can cause meshing difficulties. This is because the mesher would need to transition from extremely small mesh elements, and it will force more mesh elements around the area that aren't really needed.