Ultra-wideband RCS reduction realized by a coding diffusion metasurface

In this study, a coding diffusion metasurface (CDMS) based on a circular-polarization (CP)-maintaining metasurface is proposed for radar cross-section (RCS) reduction. The CP-maintaining metasurface can achieve ultra-wideband CP-maintaining reflection, and its main reflection phase under CP incidence can be adjusted at will by the Pancharatnam-Berry phase generated by the rotation of its unit cell, so it can be used to design CDMS. Thus, based on the CP-maintaining metasurface, the 2-bit CDMS is proposed. The simulated and measured results demonstrate that the CDMS can achieve highly effective and ultra-wideband RCS reduction under arbitrarily polarized incidences, compared with a pure metallic plate of the same size, its RCS can be reduced by more than 10 dB under normal incidence in the ultra-wide frequency band of 7.1-33.6 GHz with a relative bandwidth of 130.2%; moreover, when the incident angle is increased to 40 degrees, an ultra-wideband RCS reduction can still be achieved.