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.