help in shielding the waveguide port in a coupled microstrip using CST

it says that calculations seems to be unstable.. so i can increase the dimension of the waveguide port or i can shield it.. how can i shield it ? thanks for your help

i faced similar problems. i tried to change the port source to discrete instead of waveguide.
let me know the exact solution if you have found it.

How to shield is described in the online help directory in your cst folder. In the setup for your waveguide is an option to activate shielding. The question is if this is the solution or you have some other problems with your setup. The change from waveguide to discrete port should be considered carefully because they represent two different types of excitation.