CST floquet port set up problem

hi
i am trying to do some simulation in CST . but when i try to use FSS template which automatically set up floquet port in zmin and zmax. but when i try to run the simulation it shows that it can not run the simulation as it contains disprsive material at zmin and zmax. how i can shift the floquet port to nodispersive material. the substrate and the patch both are dispersive.

You could add space to the top plane and bottom plane,too.
And let the floquet port away from ur dispersive material.
try it