DOPPLER PHASE MODULATION EFFECT FOR NON-CONTACT ACCURATE MEASRUEMENT ...

129 Pages·2009·3.14 MB·English

DOPPLER PHASE MODULATION EFFECT FOR NON-CONTACT ACCURATE
MEASRUEMENT OF VITAL SIGNS AND OTHER PERIODIC MOVEMENTS
– FROM THEORY TO CMOS SYSTEM ON CHIP INTEGRATIONS

By

CHANGZHI LI

A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA

2009
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© 2009 Changzhi Li

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To my parents

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ACKNOWLEDGMENTS
I would like to express my sincere gratitude to my advisor Dr. Jenshan Lin for his advice,
encouragement, and mentoring throughout my PhD study. I have truly enjoyed doing research
under his guidance over the years. Moreover, Dr. Lin’s dedication to the service of the
microwave society and kindness to other people are things I will follow throughout my life. I
would also like to thank my committee members, Dr. Jian Li, Dr. William Eisenstadt, and Dr. Z.
Hugh Fan for their time and precious comments.
I am also thankful to my colleagues (Gabriel Reyes, Xiaogang Yu, Yan Yan, Chien-Ming
Lee, Austin Chen, Mingqi Chen, Lance Covert, Ching-Ku Liao, Zivin Park, Zhen Ning Low,
Raul Chinga, and Ashley Trowell) in the Radio Frequency Circuits and Systems Research Group,
for all the help and happiness they offered. My special thanks also go to my friend Jun Ling and
his advisor Dr. Jian Li for their great help on the signal processing side of my research. I would
like to mention my thanks to the University of Florida Integrated Product and Process Design
Program (IPPD). It was my great pleasure to collaborate with the IPPD students (Julie
Cummings, Jeffrey Lam, Eric Graves, and Stephanie Jimenez) and their coach Ms. Wenhsing
Wu.
I would like to thank my parents for their encouragement and unconditional support. I
dedicate this Dissertation to my family, whose love gives me the courage to my life.

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TABLE OF CONTENTS

page
ACKNOWLEDGMENTS...............................................................................................................4
LIST OF TABLES...........................................................................................................................8
LIST OF FIGURES.........................................................................................................................9
LIST OF ABBREVIATIONS........................................................................................................12
ABSTRACT...................................................................................................................................13
1 INTRODUCTION..................................................................................................................15
1.1 Background..................................................................................................................15
1.2 Recent Progresses on Non-contact Vital Sign Detection.............................................16
2 EXPERIMENT AND SPECTRAL ANALYSIS FOR OPTIMUM DESIGN OF RADIO
FREQUENCY AND RADIO ARCHITECTURE..................................................................19
2.1 Introduction..................................................................................................................19
2.2 Measurement from Four Sides of a Human Body.......................................................20
2.3 Spectral Analysis.........................................................................................................24
2.3.1 Spectral Analysis of Doppler Radar Sensor.......................................................25
2.3.2 Sensitivity..........................................................................................................25
2.3.3 Harmonic Interference.......................................................................................26
2.3.4 Residual Phase – Optimum/Null Points Manipulation......................................29
2.4 Simulation....................................................................................................................31
2.4.1 Spectrum............................................................................................................31
2.4.2 Optimum Choice of Carrier Frequency.............................................................32
2.4.2.1 Absolute detected heartbeat strength........................................................36
2.4.2.2 Detected heartbeat compared with harmonics..........................................38
2.4.2.3 Detected heartbeat compared with intermodulation tone.........................38
2.4.2.4 Summary...................................................................................................40
2.5 Experiment...................................................................................................................40
2.5.1 Observation of Harmonics.................................................................................41
2.5.2 Even Order Harmonics Dominant – Null Point.................................................42
2.5.3 Odd Order Harmonics Dominant – Optimum Point..........................................42
2.6 Conclusion...................................................................................................................43
3 A NEW METHOD AND SYSTEM FOR NON-CONTACT MEASUREMENT OF
FREQUENCY AND AMPLITUDE OF MECHANICAL VIBRATION..............................44
3.1 Introduction..................................................................................................................44
3.2 Theory and Analysis....................................................................................................45
3.3 Experimental Results...................................................................................................48
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3.4 Wide angle Incidence and the Effect on Accuracy......................................................50
3.5 Conclusion...................................................................................................................53
4 SYSTEM INTEGRATION ON BOARD LEVEL.................................................................54
4.1 Introduction..................................................................................................................54
4.2 Circuit Design and Implementation.............................................................................54
4.3 Measurement Results...................................................................................................56
5 SYSTEM INTEGRATION ON CHIP LEVEL......................................................................58
5.1 Introduction..................................................................................................................58
5.2 A 5 GHz Indirect Conversion Double Sideband Transmission Radar Sensor.............58
5.3.1 CMOS 5 GHz Indirect Conversion Radar Transceiver.....................................58
5.3.2 Baseband Circuit................................................................................................62
5.3.3 Antenna..............................................................................................................63
5.3.4 Experimental Results.........................................................................................63
5.3 A 5 GHz Direct Conversion Software Configurable Radar Sensor.............................65
5.3.1 CMOS 5 GHz Direct Conversion Radar Receiver............................................65
5.3.2 System Design Considerations..........................................................................66
5.3.3 Detailed Circuit Design......................................................................................69
5.3.3.1 LNA and preamplifier...............................................................................69
5.3.3.2 Mixers........................................................................................................71
5.3.3.3 Variable gain amplifiers............................................................................71
5.3.3.4 Bias circuits...............................................................................................72
5.3.4 Experiments.......................................................................................................74
5.4 Conclusion...................................................................................................................77
6 COMPLEX SIGNAL DEMODULATION AND RANDOM BODY MOVEMENT
CANCELLATION IN DOPPLER RADAR VITAL SIGN DETECTION............................78
6.1 Introduction..................................................................................................................78
6.2 Complex Signal Demodulation and Arctangent demodulation...................................80
6.2.1 Complex Signal Demodulation..........................................................................82
6.2.2 Arctangent demodulation...................................................................................84
6.3 Effects of Phase Offset.................................................................................................86
6.4 Simulation....................................................................................................................88
6.4.1 Ray-tracing Model.............................................................................................88
6.4.2 Demodulation without Random Body Movement.............................................89
6.4.2.1 Example I: 5.8 GHz quadrature radar.......................................................89
6.4.2.2 Example II: 24 GHz quadrature radar.......................................................91
6.4.3 Random Body Movement Cancellation.............................................................93
6.5 Experiment...................................................................................................................96
6.5.1 DC Offset Estimation in Baseband....................................................................98
6.5.2 Random Body Movement Cancellation...........................................................100
6.6 Conclusion.................................................................................................................103
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7 ADVANCED SPECTRAL ESTIMATION ALGORITHM FOR DOPPLER RADAR
NON-CONTACT VITAL SIGN DETECTION...................................................................104
7.1 Introduction................................................................................................................104
7.2 Spectral Estimation Using Periodogram....................................................................106
7.2.1 Problem Formulation.......................................................................................106
7.2.2 Periodogram.....................................................................................................108
7.3 Spectral Estimation Using RELAX...........................................................................110
7.4 Numerical and Experimental Results.........................................................................112
7.4.1 Example I.........................................................................................................113
7.4.2 Example II........................................................................................................116
7.5 Conclusion.................................................................................................................118
8 APPLICATION CASE STUDY – INFANT VITAL SIGN MONITOR.............................119
8.1 Introduction................................................................................................................119
8.2 System Architecture...................................................................................................120
8.3 Features......................................................................................................................121
8.4 Conclusion.................................................................................................................123
9 SUMMARY..........................................................................................................................124
LIST OF REFERENCES.............................................................................................................125
BIOGRAPHICAL SKETCH.......................................................................................................129

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LIST OF TABLES
Table page

2-1 Summary of heart rate detection accuracy.........................................................................23
3-1 Detection range for different pairs of harmonics...............................................................48
4-1 Building blocks and specifications used in the 4-7 GHz radar..........................................55
5-1 System specifications (power referred to 50 Ohm)...........................................................68
7-1 The RELAX algorithm....................................................................................................111

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LIST OF FIGURES
Figure page

2-1 Block diagram of the Ka-band Doppler-radar system using double side-band
transmission.......................................................................................................................21
2-2 Heart-rate comparison at 2 m distance...............................................................................22
2-3 Normalized spectrum comparison at 2 m distance for the front case and the back case
under power lever of 350 µW............................................................................................23
2-4 Bessel coefficients.............................................................................................................27
2-5 Surface formed by the values of J (4πm /λ)/J (4πm /λ) as a function of m and m ..........28
4 r 1 h r h
2-6 Simulated normalized spectrum comparison.....................................................................32
2-7 Spectral intensity of breathing fundamental, breathing harmonics, and heartbeat
fundamental........................................................................................................................33
2-8 Simulated spectrum of baseband signal.............................................................................35
2-9 Amplitude of detected heartbeat signal versus the carrier frequency................................37
2-10 Relative strength of detected heartbeat signal compared with the third order
harmonic as the carrier frequency changes........................................................................38
2-11 Relative strength of detected heartbeat signal compared with the intermodulation as
the carrier frequency changes............................................................................................39
2-12 Measured and calculated baseband spectrum when residual phase is found to be
51.770.................................................................................................................................41
2-13 Measured baseband spectrum when even order harmonics dominate, corresponding
to a null detection point......................................................................................................42
2-14 Measured baseband spectrum when odd order harmonics dominate, corresponding to
an optimum detection point...............................................................................................43
3-1 Block diagram and experimental setup..............................................................................45
3-2 Theoretical harmonic ratio as a function of the movement amplitude..............................47
3-3 Detected baseband signal and spectrum when carrier frequency is 40 GHz.....................49
3-4 Method to obtain the displacement and to check the validity of the measurement...........49
3-5 Baseband spectrum detected with the target placed 0.25m in front of the antenna...........51
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3-6 Radiation pattern of the horn antenna used in experiment and a 10×10 antenna array.....52
3-7 Measurement error of 3rd order to 1st order ratio and 4th order to 2nd order ratio by
different antennas...............................................................................................................52
4-1 The 4-7 GHz vital sign detector.........................................................................................55
4-2 Measurement results of complex demodulation................................................................57
5-1 Block diagram of the 5 GHz radar transceiver with the input/output interface.................59
5-2 Simplified circuit diagram of the 5 GHz radar transceiver................................................61
5-3 Chip microphotograph of the 5 GHz radar transceiver......................................................62
5-4 Baseband circuit for signal amplification and differential to single-ended
transformation....................................................................................................................62
5-5 Transmitted spectrum when RF-VCO tuned at the highest frequency and the lowest
frequency............................................................................................................................64
5-6 Detected baseband spectrum..............................................................................................65
5-7 Block diagram of the software configurable 5.8 GHz radar sensor chip...........................67
5-8 Schematic of the receiver chain.........................................................................................70
5-9 Bandgap bias circuit for the mixer core and mixer buffer.................................................72
5-10 Constant-Gm bias circuit for the variable gain amplifier..................................................73
5-11 Schematic of the Gm-boosted bias circuit.........................................................................73
5-12 Chip microphotograph of the 5.8 GHz radar sensor receiver............................................74
5-13 Experiment setup for non-contact vital sign detection......................................................75
5-14 Detection from the back of a human subject at 0.5m away...............................................76
5-15 Detection from the front of a human subject at 1.5m away...............................................76
6-1 Simplified block diagram for Doppler radar non-contact vital sign detection..................80
6-2 Demodulation block diagram.............................................................................................83
6-3 Ray-tracing model for 5.8 GHz radar application.............................................................87
6-4 Ray-tracing model for random body movement cancellation............................................88
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