Reconfigurable Intelligent Surface-Aided Indoor Radar Monitoring: A Feasibility Study

The application of radar technology in indoor people monitoring has opened up new avenues, such as localization and tracking, vital signs monitoring, and fall detection. Nevertheless, one of the significant challenges facing radar systems is the issue of indoor multipath propagation, which results in radar ghosts that can diminish the detection accuracy or even compromise the monitoring process entirely. This study delves into the utilization of reconfigurable intelligent surfaces (RISs) in radar-based indoor people localization. Thanks to the use of RIS, targets can be tracked from multiple orientations, achieving a more precise estimation of the propagation channel and in turn mitigating the effects of indoor multipath propagation. As a result, the detection performance of the radar system can be improved without increasing the radar's complexity. Empirical evidence gathered from experiments conducted in a laboratory environment has demonstrated the feasibility of the proposed approach in accurately locating multiple subjects in a two-dimensional (2-D) space while being able to reject radar ghosts. Practical implications of this novel approach include the development of smart building systems, Internet of Things (IoT), telemedicine, Hospital 4.0, automated nurse call solutions, ambient assisted living, firefighter tracking, and security applications.