Electromagnetic nonreciprocity in a reflectarray composed of nonlinear resonant elements

Resonant nonspecular reflection by a planar periodic structure constructed of short circular cylinders placed on a silver substrate has been simulated. Our research is focused on electromagnetic nonreciprocity that manifests itself for direct and reversed scenarios of reflection in the first diffraction order of the nonlinear cylinder array. Full-wave numerical simulation were performed and spectral reflection characteristics were obtained for different values of incident electromagnetic wave intensity. We have also studied the distribution of fields in the cylinders at reflection resonances and its effect on the degree of nonreciprocity in the direct and reversed scenarios. At frequencies where magnetic dipole moments arise from the circular displacement currents in the cylinders, nonreciprocity is more pronounced than in other types of resonant field distribution in discs.