Help with 2-wire TX-line simulation in HFSS

Hello there, How are you doing?

My apology if I have asked too many questions.

I'm having some trouble simulating a 2-wire transmission line in HFSS. I hope you can help me.

My design is pretty simple. 2 wire and load impedance is a rectangular wire of copper in the air. Using transmission line theory, I calculated that Zo is equal to roughly 358 ohm. Thus, I assigned Zg of the Lumped port in HFSS to match that.

Using transmission line theory from Pozar book, I calculated my S11 = reflection coefficient values in MATLAB.

The result I got from MATLAB is a lot different from HFSS.

I have verified my code to calculate Zo, gamma with the book problems as well as the online Tx-line calculator. In HFSS I made sure to matched Zg = Zo. However, the results are still different.

Did I miss any particular setup from HFSS which causes this error?

Thank you

toannguyen said:

My design is pretty simple. 2 wire and load impedance is a rectangular wire of copper in the air.

Click to expand...

Please give more information about the load. Is it an antenna? How did you determine the impedance.

FvM said:

Please give more information about the load. Is it an antenna? How did you determine the impedance.

Click to expand...

My apology for not providing full detail.

My goal is just to simulate a simple 2-wire Tx-line problem in the book. The load is a rectangular copper wire. I use formulas from this website (https://www.emisoftware.com/calculator/resistance-rectangular-wire/) to calculate its impedance. The result is pretty small, around 7 ohm.

Thank you

FvM said:

Please give more information about the load. Is it an antenna? How did you determine the impedance.

Click to expand...

HFSS design: (http://imgur.com/a%2FsNgu9aG) Port Impedance Zg matched to Zo: (http://imgur.com/a%2Fc5I3Jjd) S11 formula: (http://imgur.com/a%2FaUQNmTm) MATLAB result: (http://imgur.com/a%2FaxXwFIK) HFSS result: (http://imgur.com/a%2FRGrguRB)
Thank you in advance