Question on using HFSS for running S11 for two port network

[gundam]

Question on HFSS

Hi,

I'm curious why is it that when I use HFSS to run for a S11 for a two port network, I do not need to terminate with a load? Pls correct me if I'm wrong as from my limited knowledge, in network analysis we need to terminate the other port to get the S11 result.

Thanks alot

 

[haydar]

Re: Question on HFSS

Hi
Think that you work with a two port network analyzer. When you want to see S11 while two ports are connected, you cannot connect a load to other port because of the second port.
This is the same, as you try to measure S11 with either a network analyzer or HFSS.

also, I find the similar question in the forum:

 

[loucy]

Re: Question on HFSS

by definition, S11 is the reflection coefficient seen into port 1 when port 2 is matched. if you use wave port in HFSS, port 2 is terminated with the characteristic impedance of the corresponding "eigen"-mode of a transmission line having the same cross section as the plane in which port 2 lies in. This is achieved by doing some sort of calibration (numerically). For lumped port, that load impedance is assigned by you.