A Study on the Effect of Measurement Distance on the Accuracy of Millimeter-Wave Radar Sensing for Heartbeat Measurement

Millimeter-wave radar (mm-wave radar) sensing has great potential for non-contact heartbeat measurement in home monitoring. However, most of the current radar-based measurement is inaccurate. There have been studies reporting signal analysis and processing methods for improving the measuring accuracy. However, the signal-to-noise ratio (SNR) of measured signals needs further improvement. This study aims to explore the possibility of measurement distance between a mm-wave radar and the person to be measured as a key factor to improve the SNR, and thus the measurement accuracy. Two novel evaluation indexes for the quality of radar signals, reflection intensity and the SNR, were proposed, and verified with experiments. The results demonstrated a correlation between these indexes and measurement accuracy, offering insight into determining an appropriate measurement distance for improving accuracy of heartbeat measurement in home monitoring applications.