Design of Diffusive Modified Chessboard Metasurface

Abstract

In this letter, the design of ultrathin diffusive modified chessboard metasurface at microwave band is presented. Each quadrant of the conventional 2 × 2 chessboard is replaced by a small size 1-bit reflectarray exhibiting an optimized diffusive 1-bit quantized phase distribution. Furthermore, the proposed chessboard metasurface is designed in such a way to also have 180° phase shift between any adjacent quadrants (reflectarrays). A subwavelength-spaced cross-polarization rotating anisotropic unit cell, which can rotate the polarization of a linearly polarized incident wave to its orthogonal (cross polarized) component with 99% polarization conversion efficiency from 7 to 16 GHz, is used to compose a two small size 1-bit reflectarrays. The proposed unit cell and its mirror image are used to provide the required 1-bit phase states (“0°” and “180°”) of the 8 × 8 unit cells reflectarrays. The proposed diffusive metasurface is composed of four reflectarrays and has an aperture dimensions of 160 × 160 × 3.04 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . Both simulation and measurement results show that the proposed metasurface can diffuse the incident electromagnetic wave regardless of the polarization of the incident wave and under wide angle of incidence (up to 60°) with 10 dB radar cross reduction when compared to a PEC plate of same size.