Human Tracking and Vital Sign Monitoring with a Switched Phased-Array Self-Injection-Locked Radar

This paper presents a switched phased-array (SPA) radar that uses self-injection-locking (SIL) and digital beamforming (DBF) technologies to provide high sensitivity of vital sign detection and accurate azimuthal tracking of a mobile person. Advantageously, the complexity of RF transmission and reception in the proposed SPA radar is very low compared to the conventional phased array radar. In the experiment, a prototype SPA-SIL radar was implemented to operate in the 2.4 GHz ISM band. This radar can automatically track the azimuth angle of a subject and successfully detect his vital signs over a wide azimuth and distance range.