A Low-Profile Spin-Decoupled Folded Reflectarray Antenna With Dual-Circularly Polarized Beams

In this letter, a low-profile spin-decoupled folded reflectarray antenna (SDFRA) with dual-circularly polarized beam control is proposed, which can realize spin angular momentum (SAM) decoupling. Impressively, the substrate used in this antenna is reduced to three layers. The proposed SDFRA consists of a receiver-transmitter metasurface (RTMS), a polarization conversion reflection metasurface (PCRM), and a magneto-electric (ME) dipole antenna. Specifically, the RTMS can reflect the x-polarized waves and transmit its orthogonal polarization waves. Meanwhile, the transmitted waves can be decomposed into left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP) waves. To confirm the concept, a prototype is fabricated and measured. The results indicate that the 3 dB gain bandwidth of the LHCP beam and the RHCP beam are 20.89% and 21.3%, respectively. The maximum realized gain of the LHCP and RHCP beams are 20.55 dBic and 20.52 dBic, corresponding to aperture efficiencies of 19.06% and 19.19%. The experimental results are in good agreement with the simulated results. With the advantages of broadband, low profile, and low cost, this antenna provides an effective solution for single-band dual-circularly polarized beam control.