Fabry–Pérot-Based Compound All-Dielectric Huygens’ Structure for Circularly Polarized Millimeter-Wave Beamforming

An all-dielectric Fabry–Perot compound Huygens’ structure is proposed for beam-forming at the millimeter-wave (mm-wave) band for circularly polarized (CP) waves. The proposed structure is based on a symmetric unit cell in the plane of the structure, which allows for CP wave transmission, and is demonstrated in the near field of a 60 GHz right-hand CP slot array antenna. Full-wave demonstration of a uniform structure shows a negligible effect on the reflection and radiation of the antenna from 59 to 62 GHz. Full-wave simulations were further used to demonstrate a phase-gradient structure for beam-steering from 59 to 61 GHz. Finally, a difference-pattern structure was fabricated and experimentally demonstrated for operation from 61 to 62 GHz, exhibiting low reflection and good axial ratio (AR) performance across the bandwidth.