Simulating only part of a trace in HFSS

[AndyECE]

I am designing a feed system for a patch antenna. It is an SMA connector leading to a trace. I am trying to look at only the input SMA and the trace leading to the antenna, but I don't want to include the antenna because it takes a long time to simulate.

I chopped out the section of the system that I am interested. Right now, the trace goes out to the end of the circuit and terminates by touching the radiation boundary.

Is this correct? My understanding is that anything that reaches the radiation boundary is considered "gone", and so I figured that the fact that the trace doesn't actually go anywhere won't affect my return (S11).

 

[romka-04]

Hi!

Your conviction that anything that reaches the radiation boundary is considered "gone" is not COMPLETELY correct. The energy is absorbed but not ALL.

You can check this by the following way. Draw the waveguide which excited from one side and “loaded” on the radiation boundary from other side. You will see how much energy is reflected.

I think that you should put the lumped port on the other side of your line. And if you are going to join internal and outer models in future (in Ansoft Designer as example) you will need S12 of your internal model.

 

[mtu]

hi,
Can any one guide me how to model SMA or any suitable connector in HFSS for driving patch antenna?

 

[EdmundZheng]

assign two port to sma and microstrip line.