simulation for FSS with incident angle

I want to design a FSS with big attenuation at 140GHz and 90-130GHz is ts passband .I want to use metal on the substrate.I will simulate with normal incident plane wave and plane wave with incident angle separately,
and see the stability of angle of incidence of the FSS.

Now I wonder which software is best for the design.

I used quickwave 3D. It is a FDTD software, and it is fast, but it can not simulate planewave with angle.or I can not see the S-parameter with plane wave excitation

Now I am using ansoft HFSS, and i just figure out how to simulate with wave port, but not plane wave. Is the excitation " incident wave" plane wave? and how to define the angle and get the S-parameter without wave port?

The third choise is Ansoft Designer, which I just know on the website,

Could you please tell me which one is suitable for my design?
Thanks a lot!

Since it's been more than 4 months. Have you figured out your problem ?

I currently have an assignment simulating FSS (rectangular patch) on a substrate:

I have to find reflection and transmission coefficient.

Could you please share w/ us your experience about plane-wave versus excitation wave: Are they the same ?

Thanks