Dielectric waveguide - wave port excitation

[tosbadam]

I have been working on designing a dielectric waveguide. I incorporated an airbox with radiation boundary defined to enclose the entire geometry. However, when I tried defining the waveport on one of the faces of the airbox, HFSS treated the airbox face as another waveguide. The resulting modes are guided by the larger box but not the dielectric waveguide. I tried to make the airbox larger to reduce the effect of the airbox but it did not help. How can I assign the waveport correctly such that the resulting modes are guided by the dielectric waveguide only?

--- Updated Jun 23, 2023 ---

Here is excitation port definition that is on the boundary of air box

 

[PlanarMetamaterials]

You need to have some sort of boundary on the side walls here, I've found that a radiation boundary often confuses HFSS. As such, I think the best way to handle this is to make the transverse dimensions of the airbox larger than the wave port. Ensure that the longitudinal faces of the airbox are assigned as radiation boundaries as well, overlapping with the wave port.