Chessboard-coding Metasurface Antennas with Binary Defects for Anomalous Radiation: Novel and Continuous Development

This paper presents a numerical analysis of chessboard-coding metasurface antennas, focusing on the impact of binary coding defects on beamforming radiation characteristics. Chessboard-coding metasurface antennas, composed of 1-bit unit cells with binary phase distributions (0° and 180°), enable near-field wavefront control for beam steering applications. Beam tilting is achieved by introducing binary defects, which break phase continuity and affect radiation performance. This study investigates a planar antenna and examines the effects of binary defects in metasurface unit cells by analyzing reflection characteristics, impedance variations, and radiation patterns at 9 GHz. Twelve defect configurations are simulated to observe beam tilting and distortion patterns, revealing a strong dependence on defect location. The spatial distribution of defects within the metasurface lattice is categorized into inner and outer regions, according to their impact on beam characteristics. Numerical results show that binary defects can redirect beams in both azimuth and elevation. The defective cell locations in the 5 × 5 chessboard pattern reveal symmetric beam shifts in azimuth (0°, ±50°, ±110°, and ±137°) and elevation (+17.5° and +22.5°), with antenna gains ranging from 4.1 to 5.3 dBi compared to a 5.57 dBi baseline. Impedance bandwidths are observed approximately within the 8.4–9.5 GHz range. These findings offer valuable design insights for developing robust, reconfigurable metasurface antennas suited for next-generation 6G communication systems operating in the centimeter-wave band.