CST -- Specifying polarization in waveguide ports

Hi,
I'm new to CST. So forgive me if my question is elementary.
I'm simulating a split ring resonator and trying to look at its transmission and reflection spectra.
The boundary condition I'm using is the unit cell.
However, I would only like to excite my split ring resonator with a particular polarization.
I have no idea how to specify that given that the unit cell boundary condition enforces a floquet port.
Thanks.

hi there
you can go to the port settings and select TE or TM polarization for exciting your structure
regards

Is it ok to just consider 1 mode then?
Would my results be affected due to the lack of consideration of higher modes?
Thanks