rectangular groove plate polarizer at 82.6 ghz

how to assign boundry condition for rectangular groove plate polarizer?if you have any about this polarizer simulation plz send me material....

Which software you are using? If possible pls attached the project here

i tried simulation on HFSS...bt did not know abt that boundry condition...i atteched my report but chapter 2 is my hardware portion so acoording to that give me answer...