Spin-Decoupled Transmitarray With Circularly Polarized Multiplexing for Independent Quadruplex Beam Control Applications

A circularly polarized (CP) multiplexing spin-decoupled transmitarray (TA) antenna is proposed, which can realize distinct wavefront manipulation of co-polarized and cross-polarized components under left-handed circular polarization (LCP) and right-handed circular polarization (RCP) incidence, thereby enabling independent beamforming of four CP channels in transmission. By utilizing a receiver–transmitter configuration, the phase shift of each meta-atom can be independently tuned by adjusting the rotation angle of the top and bottom patches, thus achieving complete decoupling of distinct polarization component modulation with reduced complexity. As proof of the concept, a Ku-band aperture-shared TA with quadruplex channels is manufactured and experimentally measured. The measured results demonstrate good agreement with full-wave simulations. For LCP radiation, the measured results indicate that the 2-dB axial ratio (AR) and gain bandwidth for RCP/LCP are superior to 21.8% (11.4–14.2 GHz) and 16.3% (11.8–13.9 GHz), with two independent beams pointing at (10°, 0°) and (20°, 90°), respectively. Similarly, for RCP radiation, the LCP/RCP beams point at (10°, −135°) and (15°, 130°) with the measured 2-dB AR and gain bandwidth exceeding 30.3% (10.9–14.8 GHz) and 14.7% (12–13.9 GHz). In addition, the total maximum aperture efficiencies for LCP and RCP radiations reach 25.4% and 25.3% at 12.7 GHz. The proposed TA offers an alternative avenue for designing a multifunctional antenna for high-throughput satellite communications.