RFID System Simulation in HFSS

I need to simulate an RFID system. That includes an RFID Reader Antenna and an RFID Tag. I've already constructed both antennas. I don't know what to do next. What ports do I use for the two antennas?...

Have you checked out the recently formed group:

RFID Technologies

I have already posted several links concerning Antenna Design, RFID Transponder Design, etc.

I believe there is a link discussing RFID Simulation, if my memory serves me well.

Hope the info helps you in your endeavors.