Cardiac Signature Detection and Study Using Contactless Technology: Millimeter-Wave FMCW Radar

Abstract

The work presented in this article aims to detect the cardiac movement of a person in a noninvasive way and correlate it with a reference signal in the medical field: the electrocardiogram. To achieve this goal, a measurement campaign was carried out on 20 consenting individuals. On the one hand, the mechanical signal, the movement of the subject's chest induced by the heartbeat, is recorded via an FMCW radar, and on the other hand, the electrical signal of the heart is recorded via an ECG acquisition board. Signal processing functions and different filtering will allow the correlation of the radar and ECG signals. This study is conducted on apnea recordings in order to remove the impact of breathing on the movement of the chest. When the subject holds his or her breath, the two important phases of cardiac movement via radar capture can be detected: 1) the systole and 2) the diastole. The delay between the mechanical signal of the heart and the electrical signal of the heart, already explained by medicine, is well noted. The accuracy of motion detection provided by the radar allowed us to highlight the reproducibility of the chest movements detected during a capture. Their correlation with ECG data validates the proposed hypotheses.