High-efficiency single-layer corporate-feed gap waveguide based circularly polarized antenna array with compact size

Abstract

A high-efficiency, single-layer gap waveguide based circularly polarized (CP) metasurface (MTS) antenna array has been proposed at Ka-band, employing a combination of printed circuit board (PCB) and machining techniques. The coupling slot parallel to the feeding ridge is proposed, which can be beneficial for designing single-layer ridge gap waveguide (RGW) networks, avoiding the traditional cavity layer and reducing the transmission loss. The MTS elements in a 4 × 4 lattice of truncated-corner patches are etched on a single substrate layer for lightweight and low-cost, validating the concept of a compact mixed design that can be easily adapted to other printed CP antennas. A 4 × 4 MTS array prototype was fabricated and tested. The impedance bandwidth and axial ratio bandwidth are 26–31.3 GHz (18.5%) and 28.2–33 GHz (15.7%), respectively. Over the entire operating bandwidth of 28.2–31.3 GHz (10.4%), antenna radiation efficiency exceeds 82%, and the maximum realized gain at 29.2 GHz is 21.2 dBi. The designed broadband MTS antenna array is efficient, compact, and suitable for certain millimeter-wave communication applications.