High-Gain Elevational-Scanning Multibeam Planar SSPP Antenna Array With Large Ground-Clearance for Millimeter-Wave UAM Applications

This paper proposes a single-layer planar leaky-wave-antenna (LWA) array with large-ground-clearance for use in urban-air-mobility (UAM) applications. Despite minimizing the majority of antenna ground, the proposed structure provides a high-gain, low back-radiation elevational-scanning multibeam that covers the entire azimuth plane and upward elevational-plane for ensuring reliable and simultaneous UAM communications with multiple targets in three-dimensional air-space. The structure is constructed from eight branches of spoof-surface-plasmon-polariton (SSPP)-based LWA. By generating even-mode SSPP propagation with dual-peak field intensity for exciting dual-fed circular patches, proposed LWA in each branch achieves a low back-radiation fan-beam toward antenna perpendicular direction while minimizing the ground area. 360° azimuth coverage with eight 12°–beamwidth segments is then achieved by simultaneously exciting the annular array of proposed SSPP-based LWA. The proposed structure is investigated numerically and experimentally, which exhibits 10-dB impedance bandwidth (BW) of 52.52–67.86 GHz (25.5%) and 52.33–68.7 GHz (27.1%), respectively. High-gain multibeam-scanning ability for covering 22–57° in elevation plane is achieved with maximum peak gain of 12 dBi at 61 GHz and
θ
= 27°. While exhibiting high-gain multibeam radiation with low back-radiation, proposed design still remains a large ground clearance of 85% non-copper area, which makes the geometry appropriate for fluent installation and effective surface mounting of electronic components.