Numerical simulation for electromagnetic characteristics of double-layer frequency selective surfaces

A numerical simulation approach analyzing electromagnetic characteristics for dielectric-loaded double-layer frequency selective surface (FSS) with dissimilar lattice geometries is presented. Firstly, the forward and reverse waves are periodic with corresponding FSS respectively, and an explicit description of the vectorial propagating as well as of the evanescent modes is provided. Then by applying the electromagnetic field boundary conditions, matrix formulae of different Floquet mode coefficients are obtained, and a group of coupled integral equations is derived. The electromagnetic properties can be obtained by using the method of moments. The results illustrate that, as compared with single screen structure, the electromagnetic transmission properties of double-layer one have great improvements because of the coupling of evanescent modes within the dielectric region.