Hello,
1) I read a lot about radiation boundary on the web, they say that the nearest distance between radiation boundary and the simulation structure should be λ/4. However, in my case it is not λ/4. It is even on the radiation boundary.
Also, when I created another structure (box, plane, sphere...) inside of the air box and assigned it to Plane wave excitation in the same way, HFSS gives me error, it says 'Adaptive solution, process hf3d error: Failure in mesh verification'. I make the air box bigger and played with mesh, and I got the same result.
Do you have any idea what causes this problem or does my first model seems right?