Metasurface Broadband Circularly Polarized Antenna with Characteristic Mode Theory

A metasurface broadband circularly polarized antenna is proposed based on the theory of characteristic mode. The antenna is composed of a feeder layer, an air layer, and a metasurface. The theory of characteristic mode is used to analyze and predict the mode features of the metasurface. Besides, mode 1 and mode 2 working at 7GHz and 8.7GHz as the expected modes, a metasurface broadband circularly polarized antenna is designed. It is indicated by the simulation result that dB bandwidth of 5.32GHz-9.18GHz, with the relative bandwidth reaching 53.25%; 3 dB Axial Ratio bandwidth of 6.87GHz-8.93GHz, with the relative bandwidth of up to 26.07%. It can be confirmed that the antenna possesses performance of broadband circular polarization.