A Dual-Band Quad-Polarized Multi-Beam Shared-Aperture Reflectarray for Wireless Communication

This letter presents a novel dual-band quad-polarization (DBQP) reflectarray (RA) capable of independent beamforming for dual linear polarization (DLP) in the Ku-band and dual-circular polarization (DCP) in the Ka-band. The proposed RA unit cell achieves 3×3-bit phase encoding for both DCP (Ka-band) and DLP (Ku-band) with a thickness of 0.1 λ_Ku (λ_Ku is the free space wavelength at 18 GHz). A prototypes of RA, configured with four beams, is designed, fabricated, and experimentally validated. The four-beam DBQP RA exhibits peak aperture efficiencies exceeding 40% in the Ka-band and 50% in the Ku-band, with bandwidths wider than 10% (Ka-band) and 20% (Ku-band). Specifically, the peak gains and side lobe levels of the four beams are as follows: 27.6 dBic/ 21.7 dB (Left-Hand Circular Polarization), 27.8 dBic/-19.2 dB (Right Hand Circular Polarization), 24.6 dBi/-16.2 dB (X-Linear Polarization), and 24.8 dBi/-20.1 dB (Y-Linear Polarization), respectively. This high performance RA demonstrates strong potential for dual-band wireless communication applications.