Design of an ultra-thin antenna with low RCS based on phase gradient metasurface

This article proposes a novel design of an ultra-thin surface wave antenna. A simple structure of unit cell is utilized to provide sufficient phase gradient along the interface, then a low profile antenna working in the millimeter wave band is designed based on the metasurface and the generalized reflection law. The feeding part integrated on the same plane is to provide the quasiplane wave for a good match with the radiation part. The proposed antenna has a bandwidth of -10dB return loss from 33.3GHz to 36.8GHz, and radiates efficiently in the working band. Owing to the difference of the reflection phase from each unit cell, the scattered wave will not be converged to one direction efficiently, so the backward reflection is reduced compared to the conventional microstrip antenna array, resulting in radar cross section (RCS) reduction.