Design of Metasurface Broadband Circularly Polarized Antenna Based on Characteristic Mode Analysis

A broadband metasurface antenna is proposed based on characteristic mode analysis. By using a microstrip coupling slot as feed source, and a 90° phase difference is generated between the two modes, thus generating circularly polarized radiation. The antenna is composed of a metasurface, an air layer, and a feeder layer, and the metasurface structure is circularly polarized by slit and Angle cutting. The simulation results show that the antenna can achieve -10 dB bandwidth at 5.59-10.02 GHz, with the relative bandwidth of 56.8%, 3dB Axial Ratio (AR) bandwidth of 7.66-10.21 GHz, with the relative bandwidth of 28.5%.