A phased array non-contact vital signs sensor with automatic beam steering

Abstract

Doppler-based non-contact vital signs (NCVS) sensor systems have the ability to monitor heart and respiration rates of patients without physical contacts. Because the accuracy of a NCVS sensor can deteriorate quickly in a noisy or cluttered environment, and that patients confined on their beds have different physical sizes and microwave signatures and will still move naturally (though not frequently), continuous NCVS monitoring that can work well for all individuals is very difficult. Therefore, we have developed a highly directive phased-array antenna NCVS system that can perform automatic electronic beam steering for continuous NCVS monitoring with considerably improved monitoring accuracy over that obtained from the Doppler radar with a fixed beam. Our NCVS system includes an automatic beam steering algorithm, and has achieved heart rate measurement accuracy of nearly 95% within 5 beat-per-minute (BPM) vs. reference at our engineering lab.