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.