How to simulate a graphene structure in cst?

Hi,

I want to simulate a graphene stepped Impedance Filter proposed by correas serrano and diaz in CST. I just know how to build the structure in the simulator (by using CST graphne model) but I don't know how can I excite the structure? which port to use and with which settings. I mean how to find the mode that propagates in graphene structures and how to excite it afterward.

please somebody help me.

Thanks