Design of Low Band Transmission and High Band Absorption FSR Based on Coding Metasurface

In this paper, we propose a frequency selective Rasorber (FSR) based on coding metasurface. The overall structure is a traditional 2-D FSR structure. The surface of the lossy layer is a checkerboard distributed coding structure, which is composed of several square resistance film patches of the same size. The surface and back of the FSS layer are loaded with metal patches of the same size. Through the combination of topology optimization and improved estimation of distribution algorithm (IEDA), the |S21| of the designed structure is greater than -3dB in the broadband range of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0\sim 5.44\text{GHz}$</tex>. In the broadband range of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$8.30\text{GHz}\sim 18.62\text{GHz}$</tex>, the absorption rate is greater than 90%, up to 99%, with excellent high-frequency absorption performance. The research results have broad application prospects in the field of radar stealth radome.