Ultra-Broadband RCS Reduction Based on Optimized Coding “Whale-Shaped” Polarization Conversion Metasurface With Angular Stability

In this paper, we employed an efficient polarization conversion metasurface (PCM) to achieve broadband radar cross section (RCS) reduction for plane targets. Simulation results illustrate that the proposed “whale-shaped” unit achieves more than 90% polarization conversion ratio (PCR) in an ultra-broadband from 8.37 to 22.67 GHz. We combine the PCM unit into a 3
$\times $
3 scale lattice to form periodic structure. Subsequently, we employ the PCM lattice and its mirror lattice as “Lattice 0” and “Lattice 1” of digital coding. In order to achieve the best RCS reduction performance, we obtain the optimized combinational layout by utilizing information entropy theory and genetic algorithm. Different from the traditional checkerboard distribution, the optimized coding PCM realizes scattering beam diffusion in space. The fitting of measurements and simulations demonstrate that the proposed PCM realizes monostatic RCS reduction of −10dB in the ultra-broadband from 9.37 to 22.79 GHz. Simultaneously, the proposed optimized coding PCM operates over a wide-angle oblique incidence range from 0° to 45°. The proposed “whale-shaped” optimized coding PCM features both ultra-broadband operating bandwidth and high angular stability, which is informative for the practical application for PCMs.