Reconfigurable Holographic Surface-aided Distributed MIMO Radar Systems
Qian Li, Ziang Yang, Dou Li, Hongliang Zhang
TL;DR
This work introduces reconfigurable holographic surface (RHS) assisted distributed MIMO radar to achieve energy- and cost-efficient beamforming by regulating element amplitudes instead of using phase shifters. By formulating a worst-case average SINR maximization across multiple targets and constraints, the authors develop the Distributed RHS Radar Amplitude Optimization Algorithm (DRAOA) that alternates between transmit and receive amplitude optimization using SDP/SDR relaxations and Gaussian randomization to recover feasible beamformers. They demonstrate, via simulations at $f_c=30$ GHz, that RHS-based schemes outperform distributed phased-MIMO under equivalent power and hardware budgets, and reveal an optimal allocation between spatial diversity gain and coherent processing gain for fixed hardware resources. The results underscore the practical potential of RHS metamaterial antennas to enable larger apertures and improved multi-target detection with lower power and cost compared to conventional phased-array implementations.
Abstract
Distributed phased Multiple-Input Multiple-Output (phased-MIMO) radar systems have attracted wide attention in target detection and tracking. However, the phase-shifting circuits in phased subarrays contribute to high power consumption and hardware cost. To address this issue, an energy-efficient and cost-efficient metamaterial antenna array, i.e., reconfigurable holographic surface (RHS), has been developed. In this letter, we propose RHS-aided distributed MIMO radar systems to achieve more accurate multi-target detection under equivalent power consumption and hardware cost as that of distributed phased-MIMO radar systems. Different from phased arrays, the RHS achieves beam steering by regulating the radiation amplitude of its elements, and thus conventional beamforming schemes designed for phased arrays are no longer applicable. Aiming to maximize detection accuracy, we design an amplitude-controlled beamforming scheme for multiple RHS transceiver subarrays. The simulations validate the superiority of the proposed scheme over the distributed phased-MIMO radar scheme and reveal the optimal allocation of spatial diversity and coherent processing gain that leads to the best system performance when hardware resources are fixed.