Wideband RCS Enhancement Based on Phase Gradient Metasurface

In this work, a reflection phase gradient metasurface is proposed to realize wideband backscattering enhancement performance. Based on the generalized Snell's law, the phase difference between adjacent metasurface cells is calculated with specific retroreflective direction firstly. As a proof of concept, a square loop unit cell with different dimensions is then designed to achieve the effective reflection phase range. Furthermore, in order to obtain a wideband backward RCS enhancement, the metasurface unit cells are designed with 2-bit coding sequence. Simulation results show that the presented whole retrodirective metasurface can realize effective RCS enhancement in X band, compared to the same-sized PEC plate.