Ultrawideband Monostatic and Bistatic RCS Reductions for Both Copolarization and Cross Polarization Based on Polarization Conversion and Destructive Interference

Based on polarization conversion and destructive interference, a novel monolayered metasurface is proposed for ultrawideband monostatic and bistatic radar cross section (RCS) reductions for both copolarization and cross polarization. Unit cells share a simple asymmetric double arrow shape, but with variable geometry parameters, correspondingly with different polarization conversion capabilities and different reflection coefficients. The particle swarm optimization (PSO) algorithm and array theory are combined to optimize and select appropriate parameters for unit cells. The optimized unit cells (O-cells) simultaneously realize the polarization conversion and destructive interference to reduce copolarized RCS. In addition, mirrors of these O-cells (M-cells) are adopted to achieve the complete destructive interference to reduce cross-polarized RCS. Therefore, the total monostatic RCS can be greatly reduced. To improve the bistatic RCS reduction, random distribution of unit cells is carefully designed to realize diffusion patterns. In both the simulation and measurement results, a 10 dB monostatic RCS reduction at the normal incidence is achieved from 7.5 to 22.5 GHz (100% bandwidth). Furthermore, good specular and bistatic RCS reduction performances under oblique incident waves are also obtained. The proposed methodology opens up a new route for ultrawideband RCS reduction.