Beam-Reconfigurable Multi-Antenna System with Beam-Combining Technology for UAV-to-Everything Communications

Abstract

This paper proposes a beam-reconfigurable antenna for unmanned aerial vehicles (UAVs) with wide beam coverage by applying beam-combining technology to multiple antennas with different beam patterns. The proposed multi-antenna system consists of a circular patch antenna and a low-profile printed meandered monopole antenna. For beam combining, a coplanar waveguide with ground (CPW-G) structure feeding network is proposed, and it consists of two input ports, a 90 degrees hybrid coupler, a microstrip 90 degrees phase delay line, and a single-pole double-throw (SPDT) switch. It performs the role of power distribution and phase adjustment, and synthesizes the broad-side beam of the monopole antenna and the end-fire beam of the patch antenna to form the directive broadside beams in four different directions. The proposed antenna system operates at 5-5.5 GHz which covers both UAV ground control frequencies (5.03-5.09 GHz) and UAV mission frequencies (5.091-5.150 GHz). The peak gain, total efficiency, and half-power beamwidth (HPBW) of the antenna system are approximately 5.8 dBi, 76%, 145 degrees in the elevation plane, and 360 degrees in the azimuth plane respectively. Its electrical size and weight are lambda(0) x lambda(0) x 0.21 lambda(0) at 5.09 GHz and 19.2 g, respectively.