A theoretical approach analyzing electrical performance for dielectric loaded dual-layer Frequency Selective Surface (FSS) configuration with dissimilar lattice and element geometries is proposed.The forward and reverse waves are periodic with corresponding FSS respectively

and an explicit description of vectorial propagation as well as of evanescent modes is provided.A group of coupled integral equations is derived by applying tangential electromagnetic field boundary conditions

and electromagnetic properties can be obtained by moment method.Calculation results show that

dual-layer configuration can shape frequency response curves because of the coupling of evanescent modes between FSSs

and electrical performance has great improvements as compared with single-layer configuration.