A Wideband Reflectarray with Reconfigurable Polarization and Beam-Scanning by using Liquid Crystal Delay Line for Millimeter-wave

A wideband reflective unit cell based on aperture-coupled delay line is proposed that leverages the Liquid Crystal (LC) technology and controls the vertical and horizontal polarizations separately. By illuminating the unit cell with linear slant polarization and controlling the phase of vertical and horizontal polarization components through separate delay lines, the phase and polarization of the reflective wave can be dynamically controlled. The proposed unit cell can generate Right-hand and Left-Hand circular, +45 Linear, and +135 Linear polarizations with 360° phase shift control. A 20 × 20 element Reflectarray (RA) is simulated, and beam-steering is demonstrated for different polarizations only by using a single polarized horn feed. For circular polarization mode, the RA archives ±45° beam-steering range with a maximum 24.7 dBi realized gain, 20% Axial Ratio bandwidth, and 15% gain bandwidth in boresight at 29 GHz.