Contact-less measurement system for cardiopulmonary activity

This paper presents a wireless cardiopulmonary activity measurement system. This system generates a continuous wave toward a person's chest set at a distance of 1 m, then reflected to the system. Using a vector network analyzer, the phase of S21 is computed. The phase variation of S21 contains information about cardiopulmonary activity. Several processing techniques are used to separate heartbeat signal from cardiorespiratory signal either in frequency or in temporal domain. The measurements were performed simultaneously with a PC-based electrocardiogram to validate the heartbeat rate detection techniques. In conclusion, processing techniques used in this paper give accurate results.