Wave plane or waveguide port in CST

Hi,
I have read recently about wave plane in CST and its benefit to drive linear or circular polarization signal. I would like to know when to use wave plane and when to use waveguide port? I'm fully confusing about this. My goal to know what I have to use with waveguide and Microstrip antennas to get s11, far field and behaviour of linear and circular polarization.
Thanks in advance.

Hi abuantenna,
that will be waveguide port for you. You can get linear or circular characteristic of your antenna from radiation patterns.
Hope this helps.
Regards,
Element7k

Helo Element7k,
Thancks a lot for reply me.
Actually, I'm using waveguide ports and it seems no problem so far. In fact, i'd like to to drive my antennas by circular or elliptical polarization signal and see the reaction. The only way to do that seems to be plane wave.
I tried that but results are much worse than waveguide port for simple horn antenna. I think should be some special setting for plane wave. isn't it ?
I'm using 1 V/m and the propagation in z direction.
Hope the idea is clearer now.