microwave transmission line

Hi, my structure is like this: dielectric substrate with relative permitivity 2.54 and thickness 1.6mm, copper stripline and its width is 4.6mm, and one ground plane. I simulated it within Radiation boundary condtion box and Perfect Electric Conditon box seperately. But sadlly, the impedance for this structure is not 50Ohmn, which it should be. I excited this structure with Lumped Port in HFSS. Does someone know what is wrong? Thanks.

Hi scxyz
I think it can has some reasons:
1. the termination of your transmission line
2. your radiation box isn't correct
3. you have problem with your port modeling, it's better that you excited your TL with wave port

I hope it'll be helpful

Hi, Ali110

Thanks for your help.

I am sorry that I made a mistake. It is microstrip transmission line.
I set two lumped ports with 50Ohms at the end of the transmission line.

The width of the RBC or PEC box is set to be 10*stripline width
height is set to be 10*substrate height

Would you please tell me why I need to set wave port? cause as far as I know, for microstrip line, we used to use lumped port, which is the special case of the wave port.