Noninvasive Continuous Blood Pressure Monitoring Based on Wearable Radar Sensor with Preliminary Clinical Validation

This paper proposes a novel sensing system for noninvasive and continuous estimation of blood pressure (BP), which is based on a custom designed wearable 120 GHz Doppler radar sensor. With radar signals detected from brachial artery at the elbow, the moving trajectory of the pulses can be accurately demodulated with micrometer accuracy, and thus the reflective pulse transit time (RPTT) can be obtained for the prediction model to estimate blood pressure. Clinical trials have been launched with invasive blood pressure as reference. The experimental results show a great performance of the designed wearable radar sensor in the detection of weak pulse signatures. Compared to the ground truth of the invasive blood pressure, the estimated blood pressures by radar have mean errors below 3 mmHg for most subjects. The results reveal the possibility for the proposed radar-based BP estimation technique to be employed inside and outside the clinic, such as applications in the vast internet-of-things (IoT) and in-home health monitoring.