Hi, can you put you upload your project file here, as I am also working in this direction, but couldn't find solution for reflection coefficient VS angle of incidence for two layer (glass/Air) system and for trilayer system(glass/gold/Air). I used unit cell boundary conditions along x and y direction and PML with floquet ports along z direction. I get two ports i.e., Zmin and Zmax, I excite Zmin port, I get an error after critical angle "The material in port Zmax corresponds to a scan angle outside the visible space. Please change the background material to the material with the lowest product of relative permeability and relative permittivity (the lowest refraction index), or use periodic boundaries with the phase specified rather than the scan angle."
If you have done this problem then, please explain me in detail, how you did this and It would be great, if you post your project file.
Thanks,