How to set the port of the 2layers substrate in Ansys?

tony_lth said:

Thr question is how to set the port on the microstrip.

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It depends what you want to excite.

If you want the network parameters of just the microstrip mode, the wave port needs to encompass these modal fields; i.e., between the microstrip and its conductor backing. If you want some supermode that encompasses both the microstrip mode and the PPW mode of the power layer, you would want the port to cover all of these layers.

However, I note that you've used PECs in your simulation, so there shouldn't be any coupling between these modes. So I think your simulation setup as presented is correct in this respect.

PlanarMetamaterials said:

It depends what you want to excite.

If you want the network parameters of just the microstrip mode, the wave port needs to encompass these modal fields; i.e., between the microstrip and its conductor backing. If you want some supermode that encompasses both the microstrip mode and the PPW mode of the power layer, you would want the port to cover all of these layers.

However, I note that you've used PECs in your simulation, so there shouldn't be any coupling between these modes. So I think your simulation setup as presented is correct in this respect.

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In my design, the 2nd layer are GND for microstrip, and the 3rd layer is also the ground for the decoupling 2nd ground. Both the 2nd layer and the 3rd layer are GND for microstrip, so how to set the wave port in Ansys? It seems the wave port can only based on the 2nd layer or the 3rd layer.
Best,
Tony Liu

Wave ports are 2D surfaces at the edge of/or inside a simulation which through a signal exits or enters the rest of the geometry in the simulation.
The ground of the waveport in your situation could be either on 2nd layer or on 3rd layer, but not on both in the same time.

On the other hand, is recommended to place incident to the edge of the solution space with a radiation boundary active, and under your simulation setup, Analysis/Setup1/Advanced, check "Use Radiation Boundary on Ports”.

tony_lth said:

Both the 2nd layer and the 3rd layer are GND for microstrip, so how to set the wave port in Ansys?

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This might be a typical propagation mode for your system; you could check by covering all 3 of the conductors with your waveport, and exciting two modes. One of them might be the mode you are looking for.

Alternatively, you could probably excite such a custom mode by using a driven terminal simulation, and using lumped ports between the various conductors. Excite a voltage between the microstrip and your first conductive layer, and then ensure a similar voltage with an appropriate direction is applied between your second and third layer, so that the fields are in the same direction in all layers. You won't be able to (easily) get scattering parameters this way, though.