zload

Hello,

I am quite new to this (am an undergrad working with HFSS for the first time) and have a pretty basic question:

How do I get the impedance of one end of a waveguide, given that end is open and the other end is a waveport operating at TE10 mode?

I thought that Z0 for a waveguide would be ZTEM which is sqrt(permittivity/permissivity) and is frequency independent. But the graph I see in HFSS shows varying Z0 with frequency.

So far, I am thinking that Zload = ZTEM*(1+S22)/(1-S22)

My concerns are: 1. ZTEM (or Z0), in the graph, is not what I expect in this case and I only have S11, no S22 since I don't have that end defined as a port(it's just open). (Maybe a relationship between S22 and S11?)

Thanks in advance for your time and help.