Can we calculate RCS of an FSS structure using Floquet port

Hi to all;

My question is that, Can we calculate the RCS of an FSS design in HFSS by using the Floquet port?
I have been told by some one that you should use incident plan wave to excite the unit cell of FSS and for that also change the solution setup in HFSS.

Is there any way to calculate the RCS using Floquet ports along with the Master & slave boundaries?

Please guide me in this regard!

With best Regards:
M. Idrees