A Low-Frequency Portable Continuous Wave Radar System for Vital Signs Monitoring

Modalities for continuous real-time heart rate (HR) and respiration rate (RR) monitoring are a crucial diagnostic tool, specifically in early detection of potential health risks and timely intervention to reduce fatality. A low-frequency chest-wearable continuous wave (CW) radar device (RDR−SENSE) has been designed and developed for continuous monitoring of HR and RR. The developed RDR−SENSE device detects the periodic movements in the human thoracic region associated with cardio-pulmonary activities. The chest-wearable low-power RDR−SENSE device has been designed and manufactured in small size ( $5\times $ 5 cm). Five volunteers’ cardio-pulmonary activities were collected using the device in five different respiratory scenarios, and a precise signal processing algorithm was applied to derive their HR and RR data. The measured data were compared with the reference signals to evaluate the RDR−SENSE’s performance. The measured heart and RRs were highly promising in terms of accuracy. The mean absolute error was one beat per minute (BPM) for the HR and 0.75 respiration per minute (RPM) for the RR. The root mean square error was 1.55 BPM for the HR and 1.25 RPM for the RR. The developed RDR−SENSE explores the prospects of a chest-wearable, compact, low-frequency radar device for accurate continuous HR and RR measurements during seated activities that resemble daily-life study or work.