Measurements Performance of a Bioradar for Human Respiration Monitoring

Breathing pattern monitoring of humans is very important especially during long isolation in space missions. In particular, several factors can induce some breathing anomalies during the sleep, which may cause apnea episodes; an early diagnosis of such episodes is crucial for the application of an efficient therapy. Continuous wave bioradars operating in the microwave frequency range are effective contactless tools for monitoring the respiratory activity. These active systems emit a low power electromagnetic wave at a single frequency, which is reflected by the human chest. Based on the phase difference between the incident and reflected signals, it is possible to estimate and monitor the respiratory rate. In this paper, a metrological characterization of the bioradar methodology is presented. To this end, bioradar results are compared with the ground truth data recorded by a spirometer, which is a standard medical device that measures the air volume inhaled and exhaled by the subject.