Phase difference between MOM and FEM solution

Altair Forum User

Hello,
I have to characterize a dielectric material. I need to calculate the scattering parameters of the rectangular waveguide with inside it the dielectric to be characterized.
Resolving both with the MOM and then subsequently with the FEM I have a correspondence on everything, except on the S21 phase.
Who can tell me why?
Thank you.

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Mel

Hi John1989

 

The reference direction for the ports are different. This causes the 180 degree phase shift.

You can change it for the MoM port as shown.

For the FEM port, it cannot be set, and is assigned automatically internally.