High sensitivity Doppler radar system for detecting respiration and heart rate using improved isolation technique

This study presents a 14 GHz CW Doppler radar to measure respiration and heart rate. An improved antenna isolation technique is used to detect the heart rate of humans for long range detection. Arctangent demodulation without dc offset compensation can be applied because of the heterodyne receiver structure. HRV(heart rate variability) analysis of the radar system and the ECG(electrocardiogram) signal, which is measured directly, are compared. Based on the measurement results, the proposed radar detects the respiration and the heart rate with a small error rate.