Detecting Sleep-Related Breathing Disorders Using FMCW Radar

Polysomnography (PSG) is currently the sole method for detecting breathing disorders that occur during sleep, such as apnea and hypopnea. However, PSG monitoring is quite inconvenient for test subjects. This study proposes a non-contact method for detecting sleep-related breathing disorders that uses frequency-modulated continuous wave (FMCW) radar. The proposed method effectively extracts respiratory signals from radar signals and uses the degree of reduction in the amplitude of the respiratory signals and the duration of the reduction interval as data to detect breathing disorder intervals. The experimental results show that the respiratory signals extracted using the proposed method are similar to the actual respiratory signals. Furthermore, the breathing disorder intervals detected during sleep using FMCW radar are consistent with the actual apnea and hypopnea intervals as confirmed by the PSG results. These results demonstrate that the proposed method is suitable for non-contact detection of breathing disorders during sleep using FMCW radar.