A Broadband Circularly Polarized Antenna Using Transmissive Polarization Conversion Metasurface

With the rapid development of modern wireless communication technology, antennas, as a core component of the wireless communication system, have become a research focus. The axial ratio (AR) of an antenna is particularly critical to its overall performance. Increasing AR bandwidth can ensure circular polarization performance, enhance system compatibility, and improve anti-interference capabilities. This paper presents a design of a circularly polarized patch antenna based on metasurface technology. By incorporating a transmission-type polarization conversion metasurface, copper plates embedded vertically in the ground plane, and n-shaped parasitic patches, significant improvements in antenna performance are achieved. The tests show that the antenna achieves a 43.4% S₁₁ bandwidth within the frequency range of 4.94–7.68 GHz, and a 31.4% 3 dB AR bandwidth within the range of 4.83–6.43 GHz, demonstrating excellent performance. This study provides new technical support and design ideas for the field of wireless communication.