Waveguide port+periodic boundary

[nrgs]

hi all

I m trying to simulate a metallic periodic structure with the Transient solver. When i run the model ,the following warning arises: Waveguide port 1 touches periodic boundary! ......

 

[hamidrezakarami]

What is your transient solver?
I think the periodic boundary condition are used in the frequency domain and commercial software can not solved structures with periodic boundary condition in the time domain.