A Direct Phase-Tracking Doppler Radar Using Wavelet Independent Component Analysis for Non-Contact Respiratory and Heart Rate Monitoring

A continuous wave Doppler radar, operating as a phase-locked-loop in phase demodulator configuration, is proposed and in vivo demonstrated for noncontact vital signs monitoring. The radar architecture exhibits a unique precision in tracking the phase modulation caused by human cardiopulmonary activity from which heartbeat and respiration can simultaneously be extracted. The single mixer architecture is immune to the null point and does not require small-angle approximation conditions, which distinguishes it from pre-existing other approaches. This enables the proposed radar to behave highly linear, with very precise detection of phase modulations induced by any kind of movement, independently from amplitude and speed. After simulations and technical tests to validate functionality and safety of the proposed architecture, a practical setup was demonstrated on human volunteers. Wavelet independent component analysis was applied to successfully retrieve respiratory and heart rate information from the radar baseband signal.

[1]  Ii Leon W. Couch.  Digital and analog communication systems , 1983 .

[2]  Dominique Schreurs,et al.  Radar-Based Health Monitoring , 2013, 2013 IEEE MTT-S International Microwave Workshop Series on RF and Wireless Technologies for Biomedical and Healthcare Applications (IMWS-BIO).

[3]  Mehmet Rasit Yuce,et al.  Systolic Time Interval Estimation Using Continuous Wave Radar With On-Body Antennas , 2018, IEEE Journal of Biomedical and Health Informatics.

[4]  Tzyy-Sheng Horng,et al.  Single-Antenna Doppler Radars Using Self and Mutual Injection Locking for Vital Sign Detection With Random Body Movement Cancellation , 2011, IEEE Transactions on Microwave Theory and Techniques.

[5]  Tzuen-Hsi Huang,et al.  60-GHz Millimeter-Wave Life Detection System (MLDS) for Noncontact Human Vital-Signal Monitoring , 2012, IEEE Sensors Journal.

[6]  Sabine Van Huffel,et al.  Source Separation From Single-Channel Recordings by Combining Empirical-Mode Decomposition and Independent Component Analysis , 2010, IEEE Transactions on Biomedical Engineering.

[7]  G. Ramachandran,et al.  Reconstruction of sequential cardiac in-plane displacement patterns on the chest wall by laser speckle interferometry , 1991, IEEE Transactions on Biomedical Engineering.

[8]  Changzhi Li,et al.  A Review on Recent Advances in Doppler Radar Sensors for Noncontact Healthcare Monitoring , 2013, IEEE Transactions on Microwave Theory and Techniques.

[9]  Cam Nguyen,et al.  On the development of a multifunction millimeter-wave sensor for displacement sensing and low-velocity measurement , 2004, IMS 2004.

[10]  Tzyy-Sheng Horng,et al.  Detection of Concealed Individuals Based on Their Vital Signs by Using a See-Through-Wall Imaging System With a Self-Injection-Locked Radar , 2013, IEEE Transactions on Microwave Theory and Techniques.

[11]  Tzyy-Sheng Horng,et al.  A Rigorous Analysis of a Phase-Locked Oscillator Under Injection , 2010, IEEE Transactions on Microwave Theory and Techniques.

[12]  N. Suzumura,et al.  Absolute calibration of phonocardiographic microphones and measurements of chest wall vibration , 2006, Medical and biological engineering.

[13]  Steve B. Jiang,et al.  Accurate Respiration Measurement Using DC-Coupled Continuous-Wave Radar Sensor for Motion-Adaptive Cancer Radiotherapy , 2012, IEEE Transactions on Biomedical Engineering.

[14]  Changzhi Li,et al.  Null point elimination using RF phase shifter in continuous-wave Doppler radar system , 2011 .

[15]  Cam Nguyen,et al.  A displacement measurement technique using millimeter-wave interferometry , 2003 .

[16]  Alessandro Tognetti,et al.  SoC CMOS UWB Pulse Radar Sensor for Contactless Respiratory Rate Monitoring , 2011, IEEE Transactions on Biomedical Circuits and Systems.

[17]  Kaneo Mohri,et al.  Accurate mechanocardiogram sensors using amorphous star-shaped core multivibrator combined with a magnet , 1987 .

[18]  F.J. Yanovsky.  Recent researches in the field of weather radar at the National Aviation University , 2008, 2008 Microwaves, Radar and Remote Sensing Symposium.

[19]  Mari Zakrzewski,et al.  Separating respiration artifact in microwave doppler radar heart monitoring by Independent Component Analysis , 2010, 2010 IEEE Sensors.

[20]  Ke Wu,et al.  Noise and Sensitivity of Harmonic Radar Architecture for Remote Sensing and Detection of Vital Signs , 2014, IEEE Transactions on Microwave Theory and Techniques.

[21]  Tzyy-Sheng Horng,et al.  Phase- and Self-Injection-Locked Radar for Detecting Vital Signs with Efficient Elimination of DC Offsets and Null Points , 2013, IEEE Transactions on Microwave Theory and Techniques.

[22]  Paul Leroux,et al.  Analysis of an Indoor Biomedical Radar-Based System for Health Monitoring , 2013, IEEE Transactions on Microwave Theory and Techniques.

[23]  Dominique Schreurs,et al.  Contactless medical sensing , 2015, 2015 IEEE MTT-S International Microwave Symposium.

[24]  Kathleen Philips,et al.  A 1.2 nJ/bit 2.4 GHz Receiver With a Sliding-IF Phase-to-Digital Converter for Wireless Personal/Body Area Networks , 2014, IEEE Journal of Solid-State Circuits.

[25]  Changzhi Li,et al.  Random Body Movement Cancellation in Doppler Radar Vital Sign Detection , 2008, IEEE Transactions on Microwave Theory and Techniques.

[26]  Tzyy-Sheng Horng,et al.  A Novel Vital-Sign Sensor Based on a Self-Injection-Locked Oscillator , 2010, IEEE Transactions on Microwave Theory and Techniques.

[27]  T. Zwick,et al.  Millimeter-Wave Technology for Automotive Radar Sensors in the 77 GHz Frequency Band , 2012, IEEE Transactions on Microwave Theory and Techniques.

[28]  Jenshan Lin,et al.  Frequency-tuning technique for remote detection of heartbeat and respiration using low-power double-sideband transmission in the ka-band , 2006, IEEE Transactions on Microwave Theory and Techniques.

[29]  J. Lin,et al.  Experiment and Spectral Analysis of a Low-Power $Ka$-Band Heartbeat Detector Measuring From Four Sides of a Human Body , 2006, IEEE Transactions on Microwave Theory and Techniques.

[30]  F.E. Churchill,et al.  The Correction of I and Q Errors in a Coherent Processor , 1981, IEEE Transactions on Aerospace and Electronic Systems.

[31]  Franziska Hoffmann,et al.  Design Of Analog Cmos Integrated Circuits , 2016 .

[32]  André Bourdoux,et al.  Frequency-Tracking CW Doppler Radar Solving Small-Angle Approximation and Null Point Issues in Non-Contact Vital Signs Monitoring , 2017, IEEE Transactions on Biomedical Circuits and Systems.

[33]  Jenshan Lin,et al.  Optimal Carrier Frequency of Non-contact Vital Sign Detectors , 2007, 2007 IEEE Radio and Wireless Symposium.

[34]  E. M. Staderini,et al.  UWB radars in medicine , 2002 .

[35]  O. Boric-Lubeke,et al.  Wireless house calls: using communications technology for health care and monitoring , 2002 .

[36]  Changzhi Li,et al.  High Dynamic-Range Motion Imaging Based on Linearized Doppler Radar Sensor , 2014, IEEE Transactions on Microwave Theory and Techniques.

[37]  H. H. Meinel,et al.  Commercial applications of millimeterwaves: history, present status, and future trends , 1995 .

[38]  Domenico Zito,et al.  UWB CMOS Monocycle Pulse Generator , 2010, IEEE Transactions on Circuits and Systems I: Regular Papers.

[39]  I. Mostafanezhad,et al.  An RF Based Analog Linear Demodulator , 2011, IEEE Microwave and Wireless Components Letters.

[40]  André Bourdoux,et al.  Digital IF phase-tracking doppler radar for accurate displacement measurements and vital signs monitoring , 2017, 2017 IEEE MTT-S International Microwave Symposium (IMS).

[41]  Byung-Kwon Park,et al.  Arctangent Demodulation With DC Offset Compensation in Quadrature Doppler Radar Receiver Systems , 2007, IEEE Transactions on Microwave Theory and Techniques.

[42]  Tor Sverre Lande,et al.  Time-lapse imaging of human heartbeats using UWB radar , 2013, 2013 IEEE Biomedical Circuits and Systems Conference (BioCAS).

[43]  Domenico Pepe,et al.  Feasibility Study and Design of a Wearable System-on-a-Chip Pulse Radar for Contactless Cardiopulmonary Monitoring , 2008, International journal of telemedicine and applications.

[44]  Jennifer A. Rice,et al.  Automated DC Offset Calibration Strategy for Structural Health Monitoring Based on Portable CW Radar Sensor , 2014, IEEE Transactions on Instrumentation and Measurement.

[45]  Jenshan Lin,et al.  Range correlation and I/Q performance benefits in single-chip silicon Doppler radars for noncontact cardiopulmonary monitoring , 2004, IEEE Transactions on Microwave Theory and Techniques.

[46]  Marco Mercuri,et al.  Embedded DSP-Based Telehealth Radar System for Remote In-Door Fall Detection , 2015, IEEE Journal of Biomedical and Health Informatics.

[47]  Jingyu Wang,et al.  Noncontact Distance and Amplitude-Independent Vibration Measurement Based on an Extended DACM Algorithm , 2014, IEEE Transactions on Instrumentation and Measurement.