Broadband Spin-Decoupled Metasurface for Dual-Circularly Polarized Reflector Antenna Design

In this article, we theoretically and experimentally demonstrate a single-layered spin-decoupled metasurface and its application to a dual-circularly polarized reflector antenna. A developed method is first analyzed to guide the design of broadband spin-decoupled metasurface. Then, a quasi-I-shaped meta-atom, which exhibits a phase coverage of 2 pi and high cross-polarization conversion efficiency within 12-21 GHz, is accordingly designed to actualize spin-decoupled phase change by simultaneously tuning the structural parameters and self-rotation of the element. To illustrate the independent phase control of orthogonal spins, a dual-circularly polarized multiplexing reflector antenna is designed with offset configuration. The experimentally measured results of the assembled reflector antenna are in good agreement with the simulated ones, showing a peak gain of 29.5 and 29.6 dBic, peak aperture efficiency (AE) of 53% and 54%, 3 dB gain bandwidth (BW) of 13.2-20.2 GHz (41.9%) and 13.4-20.2 GHz (40.5%), and 3 dB axial ratio (AR) BW of 11.8-21 GHz (56.1%) and 11.5-22 GHz (62.7%) for left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP) radiations, respectively. The design strategy and the well-performed multiplexing reflector antenna may have promising perspective in many practical applications, for example, satellite communication system and long-distance wireless communication system.