Reflection from dielectric using HFSS

Dear all,

I have a simple problem in HFSS which is that I cannot get the reflection coefficient from dielectric correctly on 30 GHz-->35 GHz frequency range. I have 2 layers, one of them is of relative permittivity 15 and the other layer is air. If a plane wave is incident from air region to hit the dielectric, The reflected amplitude divided by incident one should be easy to get. Using waveport on the top of air layer as a source and PML on all other faces didn't help me to get the expected (constant) plot with frequency. I attached the HFSS file just in case I didn't explain well. I didn't add any excitations or Boundaries since all seems wrong to me.

Thanks in advance

It's not my area of expertise, but I would not expect the reflection to be constant with frequency. It reminds me a bit of coatings put on lenses. The reflection depends on the wavelength.

Dave

If epsilon is pure real then all frequencies should reflect similarly. I don't know much about your example but may be there was sigma in the dielectric.