HFSS: Imaging theory analysis

Hi!
I have a metal backing FSS unit cell, and I need to apply image theory to remove the ground plane and get S21 parameters and in a certain way calculate the constitutive params.

How can I achive the currents in the lower face are inverse to the current in the upper face and in such way avoid the metallic plate which produce S21=0?

Thanks in advance!

Hi humFdz ,

It depends on your excitation method, what are you using - normal incidence TEM? Also, I fail to see the point of this, because if your image is working properly the system should still reflect everything (like the PEC backing does), and S21 will be 0.

Hi
Yes you are right.
I use normal incidence with PEC PMC conditions and two wave ports with the E field oriented in an oposite directions. My goal was to retrieve the constitutive parameters of my structure but I have a constriction in the most of analysis I found, owing to S21=0 and I would want to avoid it with the theroy of image method but you are right that if you use it properly not only you get a total reflection but you can use the fields behind the ground plane to calculate the S21.
I guess that you are working on metamaterials. Have you ever dealt with this problem?

Thanks a lot!

How did you guess :) Unfortunately, I've never run into this problem. In my mind, it's similar to an absorbing material - you wouldn't normally characterize it using transmission properties.

Good Luck!