Help with Metamaterial Simulation in HFSS

Hello!

I'm trying to simulate a metamaterial srtucture in HFSS, the problem is that when i change the size of the vaccuun box, the S-parameters change too, which causes a switch on the ressonance frequency, i read the topic about the size of the air box, but i still couldn't figure out what's wrong with my setup, i add the file of my simulation, if anyone can help, i would appreciate.


Thanks advanced.

Is your radiation box size atleast lambda/4 away at the lowest frequency of your operation ?
If yes, try PML boundary setup.

-sv