S11 of planar waveguide in HFSS

[Alaaeldeen]

Hi, I have a question regarding the S11 response I get, when I simulate CPS, CPS,.. on HFSS. When I choose "Do not renormalize" in the waveport settings , I understand that the port is matched to the waveguide. Thus, I am expecting to see no reflection. However, what I notice is that S11 is very small at low frequency but increases to about -10 dB at 100 GHz. If I increased the accuracy of S, nothing new. Will am I missing something?

 

[FvM]

Do you have the waveguide terminated at both ends?

 

[Alaaeldeen]

mmm,I don't terminate the waveguides. I just put a waveport at the input and another one at the output. I choose "Do not renormalize". Thus, to my understanding, when HFSS calculates S11, HFSS assumes that the output terminal is matched

 

[FvM]

I just put a waveport at the input and another one at the output.

That's what I'd call both side termination.