Wideband RCS reduction by double-layer-plasma-based metasurface

Abstract

Radar cross-section (RCS) reduction technology is the key to stealth technology. In order to improve the RCS reduction effect of a designed checkerboard metasurface and overcome the limitation of thin-layer plasma in RCS reduction technology, a double-layer-plasma-based metasurface—composed of a checkerboard metasurface, a double-layer plasma, and an air gap between them—was investigated. Based on the principle of backscattering cancellation, we designed a checkerboard metasurface composed of different artificial magnetic conductor (AMC) units, the checkerboard metasurface can make vertically incident electromagnetic (EM) waves be reflected into four different inclined directions to achieve a RCS reduction. Full-wave simulations confirm that the double-layer-plasma-based metasurface can improve the RCS reduction effect of the metasurface and the plasma. The reason is that, in a band lower than the working band of the metasurface, the RCS reduction effect is mainly improved by the plasma layer. In the working band of the metasurface, the impedance mismatching between the air gap and first plasma layer, and the impedance mismatching between first and second plasma layers cause the scattered waves to become more dispersed, so the propagation path of the EM waves in the plasma becomes longer, increasing the absorption of the EM waves by the plasma. Thus, the RCS reduction effect is enhanced. The double-layer-plasma-based metasurface can be insensitive to the polarization of the incoming EM waves, and it can also maintain a satisfactory RCS reduction band when the incident waves are oblique.