Ultra-Wideband RCS Reduction Achieved by a Coding Phase Gradient Metasurface

In this paper, to achieve ultra-wideband radar cross section (RCS) reduction, a coding phase gradient metasurface (CPGM) is proposed by using Pancharatnam-Berry (P-B) phase. The CPGM is composed of eight types of CPGM elements, and a series of phase gradients with different directions or starting-values will be introduced in these types of CPGM elements under the same EM-wave incidence, so it can not only achieve anomalous reflection to reduce its specular RCS but also reduce the maximum bi-static RCS due to phase cancelation. The simulation results demonstrate that the CPGM has an excellent performance in RCS reduction, compared with a pure metallic plate with the same size, its specular RCS under normal incidence with arbitrary polarization can be reduced more than 10 dB in the ultra-wide frequency band of 8.8–34.8 GHz with a relative bandwidth of 119.3%, and its maximum bi-static RCS can also be reduced effectively in the ultra-wide frequency band; moreover, when the incident angle is increased to 45°, the RCS reduction can still be achieved in an ultra-wide frequency band. Finally, an effective experimental verification is carried out.