From Doppler to FMCW Radars for Non-Contact Vital-Sign Monitoring

Contactless monitoring of vital signs (e.g., respiration and heartbeats) is gaining a high interest in biomedical and healthcare applications. To that purpose, radar systems are very desired due to their unique characteristics in terms of improved sensitivity to detect small vibrations. This work reviews the traditional Doppler architecture for biomedical short-range radars and presents the recently-proposed coherent frequency-modulated continuous-wave (FMCW) scheme for improved vital-sign-monitoring tasks. The advantages of the FMCW solution in comparison with Doppler radars are emphasized. Experimental results from custom-designed and manufactured prototypes are also shown.