Wireless communication bandpass optical window with double-layer hexagon aperture FSS array

Dielectric loading in bandpass double-layer frequency selective surface design is a necessary process. The problem that dielectric loaded inducing the transmission loss in the centre of the frequency response curve is difficult to be avoided. Hexagon aperture FSS array is studied by numerical calculation and simulation analysis. The different way of loading dielectric, the different dielectric constant of double-layer FSS and the different coupling way of the two layer transmission curve have great influence on the transmission characteristics. Simulation results show that decreasing the thickness and permittivity of the dielectric can reduce the transmission loss. Besides, the sunken degree in the centre of the pass-band can be improved by extending the bandwidth. Aiming at comprehensive improving the transmission characteristics like band width, cutoff steepness, polarization and angle insensitivity and transmission loss, a modified dielectric loaded double-layer hexagon aperture FSS array structure is designed.