Broadband Circularly Polarized Antenna Based on ISGW and Polarization Conversion Metasurface

In this paper, a broadband circularly polarized antenna fed by an integrated substrate gap waveguide (ISGW) and loaded with a polarization conversion metasurface (PCM) is proposed. The antenna mainly consists of two parts: a line polarized source antenna and a line polarization to circular polarization conversion metasurface(LP-to-CP PCM). The source antenna with ISGW feed can ensure the transmission of quasi-TEM modes and reduce the energy leakage. The radiation patch adopts a
$3\times 3$
metasurface structure, which can further increase the antenna bandwidth. Finally, the LP-to-CP PCM is designed and loaded onto the source antenna to realize the circular polarization radiation of the antenna. The simulation results show that the antenna can achieve 30.6% (24.6 GHz ∼33.5 GHz) impedance bandwidth and 15.0% (26.5 GHz ∼30.7 GHz) 3dB axial ratio bandwidth, which has potential applications in modern wireless communication systems.