Metamaterial-Inspired Self-Polarizing Dual-Band Dual-Orthogonal Circularly Polarized Fabry-Pérot Resonator Antennas

This communication presents a Fabry-Pérot resonator antenna (FPRA) with the dual-band dual-orthogonal circular polarization (CP). The whole FPRA consists of a linearly polarized (LP) microstrip patch antenna and a chiral metamaterial (CMM) superstrate. The LP microstrip antenna serves as the feed system, while the CMM superstrate has the function of polarization transformation. The CMM also works as a partial reflective sheet to form an FPRA. The ray-tracing method in the circular base is introduced to describe the mechanism of this type of FPRA. Furthermore, the procedure of controlling the frequency ratio of two bands is discussed as well. An antenna prototype is fabricated to validate the simulated results. In the frequency band from 7.24 to 7.36 GHz, the proposed FPRA produces right-handed CP wave. However, left-handed CP wave is achieved when the frequency ranges from 7.96 to 8.14 GHz. The realized gains reach 12.98 dBic at 7.28 GHz and 13.25 dBic at 8 GHz, respectively.