Multi-Bit Coding Polarization Conversion Metasurface for RCS Reduction

Abstract

This paper presents a single-layer multi-bit coding polarization conversion metasurface (MCPCM) designed for the attainment of broadband and wide-angle radar cross section (RCS) reduction. The metasurface unit possesses a symmetrical structure composed of a bidirectional arrow and a defective rectangular ring, making it polarization-insensitive to electromagnetic (EM) waves. The designed metasurface unit exhibits broadband polarization conversion efficiency across the frequency spectrum of 11.2–25.6 GHz, achieving a polarization conversion rate (PCR) beyond 90% and displaying four resonance points. We obtained multi-bit phase responses with phase differences of 180°, 90°, and 45° through the optimized design of the unit's structure. A discrete artificial bee colony (DABC) algorithm optimizes the coding sequence, enhancing RCS reduction performance. Compared with an equivalently sized perfect electric conductor (PEC), the optimized MCPCM achieves over 10 dB RCS reduction within the 11–25 GHz frequency range. Additionally, the optimized MCPCM achieves a broader RCS reduction bandwidth compared to traditional chessboard-patterned metasurfaces. Furthermore, we investigated the proposed MCPCM's bistatic RCS performance, achieving substantial RCS reduction over a broad spectrum of incident angles. Simulation and measurement results validate the proposed metasurface capability for effective EM wave manipulation, demonstrating its potential for broadband and wide-angle RCS reduction.