UAV-Aided ISAC with A Rotatable Dipole Array: Joint Beamforming and Steering Optimization

In this paper, we consider integrated sensing and communication (ISAC) enabled by an unmanned aerial vehicle (UAV) hovering at a fixed position in the air. Unlike previous works, the UAV is equipped with a rotatable uniform linear array (ULA) of half-wavelength dipole antennas. This configuration allows for adaptive adjustments of beamforming, array orientation, and the radiation pattern of the dipoles to enable efficient sensing of multiple targets while maintaining communication with multiple users. Our goal is to maximize the sum of transmit beampattern gains towards all sensing targets, while ensuring quality-of-service (QoS) for each communication user through the joint optimization of beamforming and three-dimensional (3D) array steering. The formulated problem is highly nonconvex, presenting significant challenges in obtaining its solution. To address this, we employ a proximal block coordinate descent (BCD) method to decompose the problem into several low-complexity convex and manifold optimization subproblems. Simulation results demonstrate the substantial advantages of joint beamforming and array steering with the proposed rotatable dipole antenna array in UAV-aided ISAC, especially in complex ISAC environments.