Holographic Radar: Optimal Beamformer Design for Detection Accuracy Maximization

As an emerging antenna technique, reconfigurable holographic surfaces (RHSs) have drawn much attention recently as a promising solution to enable future radar systems with stringent power and cost requirements. In this paper, we propose RHS-empowered holographic radar, where two RHSs serve as transmit and receive antennas to detect a far-field target. Due to the simple and low-cost structure of metamaterial elements in the RHS, the holographic radar is able to achieve satisfactory detection performance at a smaller cost and power consumption compared with a traditional phased array radar. To maximize the detection accuracy of a holographic radar, a closed-form beamformer expression with the highest signal-to-noise ratio (SNR) is derived in order to fully exploit the benefit of incorporating RHSs. To the best of our knowledge, this is the first study on the global optimal beamformer design for RHSs. Simulation results also verify the superiority of the proposed scheme for holographic radar.

I. Introduction

Recent years have witnessed a rapid development of meta-material antenna techniques [1], [2]. As a representative type of metamaterial antenna, the reconfigurable holographic surface (RHS), which contains numerous metamaterial elements, has drawn much attention as a promising technique to empower future radar systems with stringent power and cost requirements [3], [4]. By carefully adjusting the radiation amplitudes of the elements, i.e., the beamformer of the RHS, the radiation pattern can be altered to accommodate various radar detection scenarios. Besides, the overall power consumption of the RHS is significantly lower than that of a phased array because the RHS does not rely on power-demanding components such as phase shifters. Moreover, due to the simple diode-based structure of metamaterial, the RHS elements and their feeding circuits can be manufactured by utilizing the printed circuit board (PCB) technique, resulting in an affordable and economic hardware cost [5], [6].