A microwave RCS reduction structure by antarafacial reflection design of gradient metasurface

A microwave gradient meta-surface is designed and fabricated. The structure is consist of a stack of two-dimensional (x-axis and y-axis) arrays of gradually-varied sub-wavelength elliptical rings, a dielectric substrate and a metallic ground plane. Both theoretical and experimental studies are conducted to demonstrate that the carefully designed y-axis phase gradient meta-surface supports high-efficiency y-axis reflections when a microwave plane wave incident along x-axis. Owing to the y-axis anomalous reflection, the reflected wave no longer lies in the incidence plane (XOZ plane) and leads to the reduction of monostatic RCS. Compared with previously reported gradient metasurfaces in microwave regime, our design shows an improved effective incidence angular domain. Our work may be applied to flat or complex objects in order to reduce the target monostatic RCS, such as mirror plate, corner reflector and cavity structure.