Help with 2-wire TX-line simulation in HFSS

[toannguyen]

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

 

[FvM]

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

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

 

[toannguyen]

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

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

 

[toannguyen]

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

HFSS design:

https://imgur.com/a/sNgu9aG

Port Impedance Zg matched to Zo:

https://imgur.com/a/c5I3Jjd

S11 formula:

https://imgur.com/a/aUQNmTm

MATLAB result:

https://imgur.com/a/axXwFIK

HFSS result:

https://imgur.com/a/RGrguRB

Thank you in advance