I want to create an ETM in CST Studio Suite as shown in the example at the min. 22:02 in this webinar: https://r1132100503382-eu1-3dswym.3dexperience.3ds.com/#community:39/post:uipACrxFQbmORXq12KQPhg

I want to use the ETM for both, FSSs and thin layers. However I have some questions about how to proceed:

1) What type of material should I create, ohmic sheet, surface impedance, ... ? As I want to evaluate the ETM with different incident angles, I think that I have to use the frequency domain solver with the Unit cell boundary condition. Thus, the thin panel is not an option.
2) As far as I know, I should use the Z21 parameters of the real material to create the ETM. However, how do I deal with parameters as the angle of incidence and also with the mode of propagation of the incident wave ? The Z21 parameters might change a lot depending on these parameters.