Periodic BC for metamaterial simulation in HFSS

I want to simulate metamaterial's S parameters in HFSS. I want to use periodic boundary conditions instead of PEC and PMC. I cannot use master/slave boundary counditions with waveports. Can you help me?

hi metaman,see that link
https://www.edaboard.com/ftopic252417.html
it is from cst v5.1,hope help u