24 GHz FMCW Radar for Non-Contact Respiratory Detection

Non-contact measurements of human vital signs such as heartbeat and respiration are preferably conducted to maintain the patient comfort and hygienic aspect in using the device. The non-contact measurement device of vital signs using Frequency Modulated Continuous Wave (FMCW) radar has been developed. The phase detection concept has been elaborated in improving the capability of FMCW for detecting the small displacement for a non-contact vital sign. Laboratory experiments have been performed and the results show that the developed 24 GHz FMCW radar is more accurate, can operate in real-time, and generates breathing patterns based on phase differences. Experimental results showed that the range estimation accuracy is less than 4.5 m. It meets the requirements for the safe limit of airborne virus transmission as far as 6 ft.