A Compact SIW-Fed Antenna With Wide-Angle Coverage and Beam Steering Capability for Enhanced mmW-UAV Communication

During the evolution from 5G to 6G, integrated space-air-ground communication has become a hotspot for research. Among them, unmanned aerial vehicle (UAV) communication and millimeter-wave (mmW) technology play important roles. UAV communication requires high-gain, wide-angle coverage, and flexible beam-steering antenna arrays. In this paper, we propose a compact antenna array with wide coverage and beam steering capability for mmW applications. The array is composed of three layers and fed through substrate integrated waveguide (SIW) with three ports. The antenna features a simple, horizontally symmetrical structure. By independently exciting each of the three ports, and combinations where port 2 is excited simultaneously with port 1 or port 3, the antenna generates currents that complement equivalent magnetic currents to produce beams pointing in different directions. The wide beams of the antenna can steer and cover a total range from −<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$60^{\circ }$</tex-math></inline-formula> to 240<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> across five states. Based on this design, a four-element array is fabricated and tested. Measurement results demonstrate the gains of 10.03, 10.8, and 10.5 dBi within the operational frequency range (23.7–28 GHz), with a radiation efficiency of 87.3<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\%}$</tex-math></inline-formula>. The proposed antenna features a low-profile and compact structure, achieving a coverage range of approximately 300 degrees. It is highly suitable for UAVs, and small mobile devices when integrated with an integrated chip circuit. Additionally, if matched with a phase shifter, the antenna can achieve two-dimensional scanning capability.