Review of Self-Injection-Locked Radar Systems for Noncontact Detection of Vital Signs

In recent decades, wireless healthcare detection has been demonstrated to be an efficient method for monitoring the health condition of targets; it has involved the detection of motion and vital sign signals with minimal discomfort. Self-injection-locked (SIL) radar systems exhibit several useful advantages over conventional continuous-wave (CW) radar systems in healthcare applications, including a low system complexity, high sensitivity, and high clutter immunity. Several approaches to detecting vital sign signals and locations using SIL radar systems have been proposed. This paper summarizes developments in vital sign detection and localization. Finally, some results of detecting animals using SIL radar systems are presented.