Phase Unwrapping for Heart and Breathing Rate Estimation Using mmWave FMCW Radar

Accurate measurement of heart rate and breathing rate using radar technology requires precise detection of displacements caused by chest wall movements. These vital signs are directly correlated with the displacement information, which is extracted from the phase of the returned radar signal. Consequently, the phase demodulation step is critical for the non-invasive and remote monitoring of these physiological parameters. This paper investigates the accuracy of various phase unwrapping methods through both simulation and real-time measurements using a 60 GHz Frequency Modulated Continuous Wave (FMCW) radar system. Our results demonstrate that with appropriate sampling rate selection, the conventional phase-unwrapping method exhibits superior robustness and reliability compared to alternative approaches for vital sign monitoring applications.