A real-time heart rate analysis for a remote millimeter wave I-Q sensor

Abstract

This paper analyzes heart rate (HR) information from physiological tracings collected with a remote millimeter wave (mmW) I-Q sensor for biometric monitoring applications. A parameter optimization method based on the nonlinear Levenberg-Marquardt algorithm is used. The mmW sensor works at 94 GHz and can detect the vital signs of a human subject from a few to tens of meters away. The reflected mmW signal is typically affected by respiration, body movement, background noise, and electronic system noise. Processing of the mmW radar signal is, thus, necessary to obtain the true HR. The down-converted received signal in this case consists of both the real part (I-branch) and the imaginary part (Q-branch), which can be considered as the cosine and sine of the received phase of the HR signal. Instead of fitting the converted phase angle signal, the method directly fits the real and imaginary parts of the HR signal, which circumvents the need for phase unwrapping. This is particularly useful when the SNR is low. Also, the method identifies both beat-to-beat HR and individual heartbeat magnitude, which is valuable for some medical diagnosis applications. The mean HR here is compared to that obtained using the discrete Fourier transform.

Accurate heartbeat monitoring using ultra-wideband radar

“…[12,13,14], and 94.0 GHz [15,16,17,18]. Among these studies, only a few [1,2,8] successfully measured the instantaneous heart rate, which would allow the assessment of heart-rate variability.…”

Real-Time Heart Rate Monitoring System based on Ring-Type Pulse Oximeter Sensor

“…To accomplish this, our ring sensor needs to be more complete and reliable in real dynamic environments. Therefore, we will attempt to improve our system with regard to extracting more reliable heart rates and breath rates [13][14][15].…”

Ultra-Wide Patch Antenna Array Design at 60 GHz Band for Remote Vital Sign Monitoring with Doppler Radar Principle

“…In the recent years, millimetre-wave (MMW) frequencies (30-300 GHz) have drawn a remarkable research interest for RVSM implications [23,[27][28][29][30][31][32][33][34][35]. The main motives of RVSM at MMW frequencies include (i) improvement in the detection accuracy by employing shorter wavelength of the signal, (ii) smaller form factor for the device compactness and (iii) possibility of more subject focused signal transmission and reception to avoid the interference from the unwanted side reflections [22,[33][34][35].…”

“…The main motives of RVSM at MMW frequencies include (i) improvement in the detection accuracy by employing shorter wavelength of the signal, (ii) smaller form factor for the device compactness and (iii) possibility of more subject focused signal transmission and reception to avoid the interference from the unwanted side reflections [22,[33][34][35]. From MMW band, 60 GHz band (57-66 GHz) has drawn more attraction because this band is free of licence and is quite mature due to its extensive use for several other wireless services [27].…”