Could everyone help me?Is it have to be in driven mode of SIW design?Is Eigenmode ok?

I'm designing a SIW in HFSS, when in the Eigenmode, the boundary of substrate can't be determined to radiation. While in Driven mode, the radiation boundary works.
I just want to know the resonance frequency and Q factor of SIW. How can I do that? Please help. It's highly appreciated.