A Wideband Optically Transparent Reflectarray Antenna With Circular Polarization

This letter pioneers the development of an optically transparent reflectarray antenna (OTRA) operating with circular polarization, catering to the future integration of communication and energy harvesting systems. A novel via-free magneto–electric dipole unit design is presented, which incorporates a diagonal strip to generate an electric resonance through the connected patches. In contrast, the isolated patches form a circulating electric loop with the ground plane to induce a magnetic resonance. Consequently, the proposed unit can possess an antiphase response between its optical axes for geometric phasing, realizing a wideband circularly polarized unit over a fragile transparent substrate. Subsequently, a 16-by-16 OTRA prototype is fabricated using metal meshes as the transparent conductive films and low-loss quartz glass as the dielectric substrate, characterized by a low profile, single-layer construction, and the elimination of air gaps. Ultimately, the proposed OTRA prototype is fed by a fully metallic complementary array. The experimental results manifest a wide 3 dB overlapped bandwidth of 35.2% and a high light transmittance of 80%. © 2025 IEEE.