Radar Sensing using Dual-Beam Reconfigurable Intelligent Surface

TL;DR

This paper investigates how practical phase tuning of reconfigurable intelligent surfaces affects radar sensing performance around corners, comparing ideal and quantized phase configurations through simulations and measurements.

Contribution

It introduces a dual-beam RIS configuration with practical phase tuning and benchmarks its performance against ideal configurations and metal plates.

Findings

Dual-beam RIS enhances radar coverage around corners.

Quantized phase tuning achieves comparable performance to ideal phase tuning.

Experimental results validate simulation predictions.

Abstract

Around-the-corner radar sensing offers an opportunity for the radar to exploit multipath scattering along walls to detect targets beyond blockages. However, the radar detection performance is limited to spotting uncooperative targets at specular angles. Recently, reconfigurable intelligent surfaces (RIS) involving metasurfaces with tunable unit cells have been researched for enhancing radar coverage around corners by directing beams towards non-specular angles. This article examines how practical considerations regarding the phase tuning of unit cells impact the RIS performance. Specifically, we examine the radar cross-section (RCS) obtained from two RIS configurations: In the first, each atom of the RIS is tuned based on a theoretical analog phase shift to realize idealized one-beam patterns at the desired angles. In the second configuration, each atom of the RIS is tuned based on a low-complexity, one-bit quantized element phase shift, which results in dual symmetric beams. The RIS configurations are then benchmarked with a metal plate of similar dimensions in both simulations and measurements.