Design of artificial magnetic conductors by using multilayered frequency selective surfaces

In this paper, multilayered dielectric structures in conjunction with a Frequency Selective Surface (FSS) screen and a perfectly electric conducting (PEC) ground plane are used for realizing high-impedance surfaces, the latter behaving like an artificial magnetic conductor (AMC) in a certain frequency range. The inclusion of the dielectric layers allows us to enhance the angular performance of the AMC as well as the bandwidth of the device. All the presented solutions are derived by using a genetic algorithm synthesis procedure. The genetic algorithm (GA) resorts to an electromagnetic solver based on the Methods of Moments (MoM) to describe the scattering behavior of the structure. In particular, the GA determines the permittivity and the thickness of each dielectric layer and the shape and the dimensions of the FSS screen. The synthesized structure are discussed with particular reference to the frequency response and to the robustness of the solution with respect to the angle of illumination.