Novel Single/Dual Circularly Polarized Antennas Based on Polarization-Conversion Reflective Metasurfaces

Abstract

We propose single/dual circularly-polarized (CP) antennas based on reflective metasurfaces with cross-polarization conversion. By suspending a probe-fed printed bow-tie dipole or a crossed bowtie dipole above the reflective polarization-conversion metasurface and appropriately tuning the distance between them, a single-CP or a dual-CP antenna is generated. The theoretical design principle on this novel CP antenna structure has been discussed. Simulations and experiments are conducted to validate the design principle. The measured results show that the proposed single-CP antenna has achieved a 3-dB axial ratio (AR) bandwidth of 8.0%, from 12.67 to 13.72 GHz, and a peak gain of 8.03 dBi, while the dual-CP antenna exhibits a dual-CP AR bandwidth of 7.1%, from 13.09 to 14.05 GHz, and peak gains of 8.49 dBi and 7.03 dBi for left-handed circular polarization (LHCP) and right-handed circular polarization (RHCP), respectively. The measured isolation between the two ports of the dual-CP antenna is less than −20 dB. The operating frequency of the proposed antennas can be easily scaled to other frequencies that are applied to some specific wireless applications.