Millimeter-Wave Sliding-Aperture Multibeam Transmitarray With 2-D Scan Capability and Low Scan Loss

To address the severe path loss degradation in the millimeter-wave band and its consequential significant reduction in received signal-to-noise ratio, high-gain antennas supporting 2-D beam scanning are critically required. This letter proposes a sliding-aperture 2-D beam-scanning transmitarray (TA) solution. The proposed TA comprises 21 × 41 unit cells, and each unit cell integrates a four-layer metallic Jerusalem cross-slot structure, achieving transmission amplitude within 1.3 dB and phase coverage of 360°. By sliding the feeding source above the aperture along linear and cylindrical trajectories for horizontal and vertical polarization, respectively, 2-D beam steering is realized. Finally, the proposed sliding-aperture TA is fabricated and measured, with measured results showing good agreement with simulated results. The proposed sliding-aperture TA achieves continuous beam coverage of ±40° in the θ direction and ±180° in the φ direction, realizing a peak gain of 24.5 dBi and scan loss of 0.8 dB. Comparative analysis with other multibeam antennas demonstrates that the proposed sliding-aperture TA exhibits significant advantages, including low scan loss, high gain, and wide-angle 2-D coverage, which show broad application in millimeter-wave communication and radar systems.