Single-antenna phase- and self-injection-locked radar for vital sign sensor module miniaturization

A single-antenna phase- and self-injection-locked radar is developed for module miniaturization and robust vital-sign monitoring. The expensive circulator is removed and the antenna is directly connected with the RF VCO to sense the Doppler motions. Time and frequency domain analyses reveal that the radar possesses the advantages of high SNR and suitable for long-range detection with low radiated power. Experiments demonstrate successful detection of respiration and heartbeat rates up to 4 m.