A Broadband Circularly Polarized Antenna Based on Transparent Conformal Metasurface

A circularly polarized antenna based on the transparent conformal polarization-conversion metasurface is proposed. The designed meta-surface unit is an ellipse rotating 45° with a rectangular slot. The three metasurface cells are arranged in a group and rotated 90° around the feed antenna. The metasurface is printed on transparent and conformal PET while also possessing low-profile characteristics. By using this method, polarization conversion of the antenna is achieved without damaging the original antenna structure, thus extending the circular polarization bandwidth of the antenna. The simulated and measured results show that the −10 dB bandwidth of the antenna is 3.9–4.7 GHz, the axial ratio is less than 3 dB. The meta-surface effectively expands the circular polarization bandwidth of the antenna from 100 MHz to 800 MHz. The radiation efficiency of the antenna exceeds 60%, and the peak gain is more than 5 dBi. The radiation patterns show that the antenna has right-handed polarization and obvious directional radiation characteristics. The meta-surface design effectively broadens the circular polarization bandwidth of the antenna, making it suitable for circularly polarized communication systems operating in the C-band frequency range.