Danick Briand obtained his PhD degree in the field of micro-chemical systems from the Institute of Microtechnology (IMT), University of Neuchatel, Switzerland, in 2001. He is currently a team leader at EPFL IMT Samlab in the field of EnviroMEMS, Energy and Enviromental MEMS. He has been awarded the Eurosensors Fellowship in 2010. He has been author or co-author on more than 150 papers published in scientific journals and conference proceedings. He is a member of several scientific and technical conference committees in the field of sensors and MEMS, participating also in the organization of workshop and conferences. His research interests in the field of sensors and microsystems include environmental and energy MEMS.Eric M. Yeatman has been a member of academic staff in Imperial College London since 1989, and Professor of Micro-Engineering since 2005. He is Deputy Head of the Department of Electrical and Electronic Engineering, and has published more than 160 papers and patents on optical devices and materials, and micro-electro-mechanical systems. In 2011 he was awarded the Royal Academy of Engineering Silver Medal. He has been principal or co-investigator on more than 20 research projects, and has acted as a design consultant for several international companies. His current research interests are in radio frequency and photonic MEMS devices, energy sources for wireless devices, and sensor networks.

"The book is loaded with ideas using a wide range of different energy harvesting methods with detailed explanations of the principles of each method and new materials being used to take advantage of the surrounding energy...Engineers interested in energy harvest­ing will find this book to be a very good resource for learning about new methods for parasitically powering low power electronic devices." (IEEE Electrical Insulation 17/03/2017)

• About the Volume Editors XVIIList of Contributors XIX1 Introduction to Micro Energy Harvesting 1Danick Briand, Eric Yeatman, and Shad Roundy1.1 Introduction to the Topic 11.2 Current Status and Trends 31.3 Book Content and Structure 42 Fundamentals of Mechanics and Dynamics 7Helios Vocca and Luca Gammaitoni2.1 Introduction 72.2 Strategies for Micro Vibration Energy Harvesting 82.2.1 Piezoelectric 92.2.2 Electromagnetic 102.2.3 Electrostatic 112.2.4 From Macro to Micro to Nano 112.3 Dynamical Models for Vibration Energy Harvesters 122.3.1 Stochastic Character of Ambient Vibrations 142.3.2 Linear Case 1: Piezoelectric Cantilever Generator 142.3.3 Linear Case 2: Electromagnetic Generator 152.3.4 Transfer Function 152.4 Beyond Linear Micro-Vibration Harvesting 162.4.1 Frequency Tuning 162.4.2 Multimodal Harvesting 172.4.3 Up-Conversion Techniques 172.5 Nonlinear Micro-Vibration Energy Harvesting 182.5.1 Bistable Oscillators: Cantilever 192.5.2 Bistable Oscillators: Buckled Beam 212.5.3 Monostable Oscillators 232.6 Conclusions 24Acknowledgments 24References 243 Electromechanical Transducers 27Adrien Badel, Fabien Formosa, andMickaël Lallart3.1 Introduction 273.2 Electromagnetic Transducers 273.2.1 Basic Principle 273.2.1.1 Induced Voltage 283.2.1.2 Self-Induction 283.2.1.3 Mechanical Aspect 293.2.2 Typical Architectures 303.2.2.1 Case Study 303.2.2.2 General Case 333.2.3 Energy Extraction Cycle 333.2.3.1 Resistive Cycle 343.2.3.2 Self-Inductance Cancelation 343.2.3.3 Cycle with Rectification 353.2.3.4 Active Cycle 363.2.4 Figures of Merit and Limitations 363.3 Piezoelectric Transducers 373.3.1 Basic Principles and Constitutive Equations 373.3.1.1 Physical Origin of Piezoelectricity in Ceramics and Crystals 373.3.1.2 Constitutive Equations 383.3.2 Typical Architectures for Energy Harvesting 393.3.2.1 Modeling 393.3.2.2 Application to Typical Configurations 403.3.3 Energy Extraction Cycles 413.3.3.1 Resistive Cycles 413.3.3.2 Cycles with Rectification 433.3.3.3 Active Cycles 433.3.3.4 Comparison 433.3.4 Maximal Power Density and Figure of Merit 443.4 Electrostatic Transducers 453.4.1 Basic Principles 453.4.1.1 Gauss’s Law 453.4.1.2 Capacitance C0 453.4.1.3 Electric Potential 463.4.1.4 Energy 463.4.1.5 Force 473.4.2 Design Parameters for a Capacitor 473.4.2.1 Architecture 473.4.2.2 Dielectric 483.4.3 Energy Extraction Cycles 483.4.3.1 Charge-Constrained Cycle 493.4.3.2 Voltage-Constrained Cycle 503.4.3.3 Electret Cycle 513.4.4 Limits 513.4.4.1 Parasitic Capacitors 513.4.4.2 Breakdown Voltage 533.4.4.3 Pull-In Force 533.5 Other Electromechanical Transduction Principles 533.5.1 Electrostrictive Materials 533.5.1.1 Physical Origin and Constitutive Equations 533.5.1.2 Energy Harvesting Strategies 543.5.2 Magnetostrictive Materials 553.5.2.1 Physical Origin 553.5.2.2 Constitutive Equations 563.6 Effect of the Vibration Energy Harvester Mechanical Structure 563.7 Summary 58References 594 Thermal Fundamentals 61Mathieu Francoeur4.1 Introduction 614.2 Fundamentals of Thermoelectric Power Generation 624.2.1 Overview of Nanoscale Heat Conduction and the Seebeck Effect 624.2.2 Heat Transfer Analysis ofThermoelectric Power Generation 644.3 Near-FieldThermal Radiation andThermophotovoltaic Power Generation 664.3.1 Introduction 664.3.2 Theoretical Framework: Fluctuational Electrodynamics 674.3.3 Introduction toThermophotovoltaic Power Generation and Physics of Near-Field Radiative Heat Transfer between Two Bulk Materials Separated by a Subwavelength Vacuum Gap 704.3.4 Nanoscale-Gap Thermophotovoltaic Power Generation 764.4 Conclusions 80Acknowledgments 80References 815 Power Conditioning for Energy Harvesting – Theory and Architecture 85Stephen G. Burrow and Paul D.Mitcheson5.1 Introduction 855.2 The Function of Power Conditioning 855.2.1 Interface to the Harvester 865.2.2 Circuits with Resistive Input Impedance 875.2.3 Circuits with Reactive Input Impedance 895.2.4 Circuits with Nonlinear Input Impedance 905.2.5 Peak Rectifiers 905.2.6 Piezoelectric Pre-biasing 925.2.7 Control 945.2.7.1 Voltage Regulation 945.2.7.2 Peak Power Controllers 965.2.8 System Architectures 975.2.8.1 Start-Up 975.2.9 Highly Dynamic Load Power 985.3 Summary 100References 1006 ThermoelectricMaterials for Energy Harvesting 103Andrew C.Miner6.1 Introduction 1036.2 Performance Considerations in Materials Selection: zT 1036.2.1 Properties of Chalcogenides (Group 16) 1066.2.2 Properties of Crystallogens (Group 14) 1066.2.3 Properties of Pnictides (Group 15) 1076.2.4 Properties of Skutterudites 1086.3 Influence of Scale on Material Selection and Synthesis 1106.3.1 Thermal Conductance Mismatch 1116.3.2 Domination of Electrical Contact Resistances 1126.3.3 Domination of Bypass Heat Flow 1136.3.4 Challenges inThermoelectric Property Measurement 1136.4 Low Dimensionality: Internal Micro/Nanostructure and Related Approaches 1146.5 Thermal Expansion and Its Role in Materials Selection 1156.6 Raw Material Cost Considerations 1166.7 Material Synthesis with Particular Relevance to Micro Energy Harvesting 1166.7.1 Electroplating, Electrophoresis, Dielectrophoresis 1176.7.2 Thin andThick Film Deposition 1186.8 Summary 118References 1197 Piezoelectric Materials for Energy Harvesting 123Emmanuel Defay, Sébastien Boisseau, and Ghislain Despesse7.1 Introduction 1237.2 What Is Piezoelectricity? 1237.3 Thermodynamics: the RightWay to Describe Piezoelectricity 1257.4 Material Figure of Merit: the Electromechanical Coupling Factor 1267.4.1 Special Considerations for Energy Harvesting 1287.5 Perovskite Materials 1297.5.1 Structure 1297.5.1.1 Ferroelectricity in Perovskites 1297.5.1.2 Piezoelectricity in Perovskites: Poling Required 1317.5.2 PZT Phase Diagram 1317.5.3 Ceramics 1327.5.3.1 Fabrication Process 1327.5.3.2 Typical Examples for Energy Harvesting 1347.5.4 Bulk Single Crystals 1357.5.4.1 Perovskites 1357.5.4.2 Energy Harvesting with Perovskites Bulk Single Crystals 1357.5.5 Polycrystalline PerovskitesThin Films 1367.5.5.1 Fabrication Processes 1367.5.5.2 Energy Harvesting with Poly-PZT Films 1367.5.6 Single-Crystal Thin Films 1377.5.6.1 Fabrication Process 1377.5.6.2 Energy Harvesting with SC Perovskite Films 1377.5.7 Lead-Free 1387.5.7.1 Energy Harvesting with Lead-Free Materials 1397.6 Wurtzites 1397.6.1 Structure 1397.6.2 Thin Films and Energy Harvesting 1407.6.3 Doping 1417.7 PVDFs 1417.7.1 Structure 1417.7.2 Synthesis 1437.7.3 Energy Harvesters with PVDF 1437.8 Nanomaterials 1437.9 Typical Values for the Main Piezoelectric Materials 1447.10 Summary 145References 1458 Electrostatic/Electret-Based Harvesters 149Yuji Suzuki8.1 Introduction 1498.2 Electrostatic/Electret Conversion Cycle 1498.3 Electrostatic/Electret Generator Models 1518.3.1 Configuration of Electrostatic/Electret Generator 1518.3.2 Electrode Design for Electrostatic/Electret Generator 1538.4 Electrostatic Generators 1568.4.1 Design and Fabrication Methods 1568.4.2 Generator Examples 1588.5 Electrets and Electret Generator Model 1608.5.1 Electrets 1608.5.2 Electret Materials 1618.5.3 Charging Technologies 1628.5.4 Electret Generator Model 1638.6 Electret Generators 1688.7 Summary 171References 1719 Electrodynamic Vibrational Energy Harvesting 175Shuo Cheng, Clemens Cepnik, and David P. Arnold9.1 Introduction 1759.2 Theoretical Background 1789.2.1 Energy Storage, Dissipation, and Conversion 1789.2.2 Electrodynamic Physics 1799.2.2.1 Faraday’s Law 1799.2.2.2 Lorentz Force 1809.2.3 Simplified Electrodynamic Equations 1809.3 Electrodynamic Harvester Architectures 1819.4 Modeling and Optimization 1839.4.1 Modeling 1849.4.1.1 Lumped Element Method 1849.4.1.2 Finite Element Method 1889.4.1.3 Combination of Lumped Element Model and Finite Element Model 1899.4.2 Optimization 1909.5 Design and Fabrication 1919.5.1 Design of Electrodynamic Harvesters 1929.5.2 Fabrication of Electrodynamic Harvesters 1949.6 Summary 196References 19710 Piezoelectric MEMS Energy Harvesters 201Jae Yeong Park10.1 Introduction 20110.1.1 The General Governing Equation 20210.1.2 Design Consideration 20310.2 Development of Piezoelectric MEMS Energy Harvesters 20410.2.1 Overview 20410.2.2 Fabrication Technologies 20510.2.3 Characterization 21110.2.3.1 Frequency Response 21110.2.3.2 Output Power of Piezoelectric MEMS Energy Harvesters 21110.3 Challenging Issues in Piezoelectric MEMS Energy Harvesters 21310.3.1 Output Power 21310.3.2 Frequency Response 21510.3.3 Piezoelectric Material 21710.4 Summary 218References 21811 Vibration Energy Harvesting fromWideband and Time-Varying Frequencies 223Lindsay M.Miller11.1 Introduction 223Contents XI11.1.1 Motivation 22311.1.2 Classification of Devices 22311.1.3 General Comments 22511.2 Active Schemes for Tunable Resonant Devices 22511.2.1 Stiffness Modification for Frequency Tuning 22611.2.1.1 Modify L 22611.2.1.2 Modify E 22711.2.1.3 Modify keff Using Axial Force 22711.2.1.4 Modify keff Using an External Spring 22911.2.1.5 Modify keff Using an Electrical External Spring 23111.2.2 Mass Modification for Frequency Tuning 23211.3 Passive Schemes for Tunable Resonant Devices 23211.3.1 Modify meff by Coupling Mass Position with Beam Excitation 23311.3.2 Modify keff by Coupling Axial Force with Centrifugal Force from Rotation 23411.3.3 Modify L by Using Centrifugal Force to Toggle Beam Clamp Position 23411.4 Wideband Devices 23511.4.1 Multimodal Designs 23611.4.2 Nonlinear Designs 23711.5 Summary and Future Research Directions 24011.5.1 Summary of Tunable andWideband Strategies 24011.5.2 Areas for Future Improvement in Tunable andWideband Strategies 24111.5.2.1 Tuning range and resolution 24111.5.2.2 Tuning sensitivity to driving vibrations 24211.5.2.3 System Size considerations 242References 24312 Micro Thermoelectric Generators 245Ingo Stark12.1 Introduction 24512.2 Classification of Micro Thermoelectric Generators 24712.3 General Considerations for MicroTEGs 25012.4 Micro Device Technologies 25212.4.1 Research and Development 25312.4.1.1 Electrodeposition 25312.4.1.2 Silicon-MEMS Technology 25312.4.1.3 CMOS-MEMS Technology 25412.4.1.4 Other 25512.4.2 Commercialized Micro Technologies 25712.4.2.1 Micropelt Technology 25712.4.2.2 Nextreme/Laird Technology 25812.4.2.3 Thermogen Technology 25912.5 Applications of Complete Systems 26012.5.1 Energy-Autonomous Sensor for Air Flow Temperature 26112.5.2 Wireless Pulse Oximeter SpO2 Sensor 26112.5.3 Intelligent Thermostatic Radiator Valve (iTRV) 26212.5.4 Wireless Power Generator Evaluation Kit 26312.5.5 Jacket-IntegratedWireless Temperature Sensor 26312.6 Summary 264References 26513 Micromachined Acoustic Energy Harvesters 271Stephen Horowitz and Mark Sheplak13.1 Introduction 27113.2 Historical Overview 27213.2.1 A Brief History 27213.2.2 Survey of Reported Performance 27413.3 Acoustics Background 27613.3.1 Principles and Concepts 27613.3.2 Fundamentals of Acoustics 27613.3.3 Challenges of Acoustic Energy Harvesting 27713.4 Electroacoustic Transduction 27713.4.1 Modeling 27813.4.1.1 Lumped Element Modeling (LEM) 27813.4.1.2 Equivalent Circuits 27913.4.1.3 Transduction 28013.4.1.4 Numerical Approaches 28113.4.2 Impedance Matching and Energy Focusing 28113.4.3 Transduction Methods 28113.4.3.1 Piezoelectric Transduction 28113.4.3.2 Electromagnetic Transduction 28213.4.3.3 Electrostatic Transduction 28213.4.3.4 Comparative Analysis 28313.4.4 Transduction Structures 28413.4.4.1 Structures for Impedance Matching 28413.4.4.2 Structures for Acoustical to Mechanical Transduction 28613.5 Fabrication Methods 28813.5.1 Materials 28813.5.2 Processes 28913.6 Testing and Characterization 28913.7 Summary 290Acknowledgments 290References 29014 Energy Harvesting from Fluid Flows 297Andrew S. Holmes14.1 Introduction 29714.2 Fundamental and Practical Limits 298Contents XIII14.3 MiniatureWind Turbines 30114.3.1 Scaling Effects in MiniatureWind Turbines 30214.3.1.1 Turbine Performance 30214.3.1.2 Generator and Bearing Losses 30514.4 Energy Harvesters Based on Flow Instability 30614.4.1 Vortex Shedding Devices 30714.4.2 Devices Based on Galloping and Flutter 31014.5 Performance Comparison 31614.6 Summary 317References 31715 Far-Field RF Energy Transfer and Harvesting 321Hubregt J. Visser and Ruud Vullers15.1 Introduction 32115.2 Nonradiative and Radiative (Far-Field) RF Energy Transfer 32215.2.1 Nonradiative Transfer 32215.2.2 Radiative Transfer 32315.2.3 Harvesting versus Transfer 32415.3 Receiving Rectifying Antenna 32615.3.1 Antenna–Rectifier Matching 32615.3.1.1 Voltage Boosting Technique 32715.3.1.2 Antenna Matched to Rectifier 32815.3.1.3 Antenna Not Matched to the Rectifier/Multiplier 32915.3.1.4 Consequences for the Rectifier and the Antenna Design 33015.4 Rectifier 33015.4.1 RF Input Impedance 33115.4.2 DC Output Voltage 33215.4.3 Antenna 33415.4.3.1 50 Ω Antenna 33515.4.3.2 Complex Conjugately Matched Antenna 33515.4.4 Rectenna Results 33615.4.5 Voltage Up-Conversion 33915.5 Transmission 34015.6 Examples and Future Perspectives 34115.7 Conclusions 344References 34416 Microfabricated Microbial Fuel Cells 347Hao Ren and Junseok Chae16.1 Introduction 34716.2 Fundamentals of MEMS MFC 34816.2.1 Operation Principle 34816.2.1.1 Structure 34816.2.1.2 Materials 35016.2.2 Critical Parameters for Testing 35016.2.2.1 Anode and Cathode Potential, the Total Cell Potential 35016.2.2.2 Open Circuit Voltage (EOCV) 35116.2.2.3 Areal/Volumetric Current Density and Areal/Volumetric Power Density 35116.2.2.4 Internal Resistance and Areal Resistivity 35216.2.2.5 Efficiency 35316.3 Prior Art MEMS MFCS 35416.4 FutureWork 35516.4.1 Reducing Areal Resistivity 35516.4.1.1 Applying Materials with High Surface-Area-to-Volume Ratio 35516.4.1.2 Mitigating Oxygen Intrusion 35816.4.2 Autonomous Running 35916.4.3 Elucidating the EET Mechanism 359References 35917 Micro Photovoltaic Module Energy Harvesting 363Shunpu Li ,WensiWang, NingningWang, Cian O’Mathuna, and Saibal Roy17.1 Introduction 36317.1.1 p-n Junction and Crystalline Si Solar Cells 36317.1.2 Amorphous Silicon Solar Cell 36617.1.3 CIGS and CdTe Solar Cell Development 36717.1.4 Polymer Solar Cell 37017.1.5 Dye-Sensitized Solar Cells (DSSC) 37317.2 Monolithically Integration of Solar Cells with IC 37517.3 Low-Power Micro Photovoltaic Systems 37617.3.1 Maximum Power Point Tracking 37617.3.2 Output Voltage Regulation 37917.3.3 Indoor-Light-PoweredWireless Sensor Networks – a Case Study 38017.4 Summary 382References 38318 Power Conditioning for Energy Harvesting – Case Studies and Commercial Products 385Paul D.Mitcheson and Stephen G. Burrow18.1 Introduction 38518.2 Submilliwatt Electromagnetic Harvester Circuit Example 38618.3 Single-Supply Pre-biasing for Piezoelectric Harvesters 38818.4 Ultra-Low-Power Rectifier and MPPT for Thermoelectric Harvesters 39218.5 Frequency Tuning of an Electromagnetic Harvester 39318.6 Examples of Converters for Ultra-Low-Output Transducers 39618.7 Power Processing for Electrostatic Devices 39718.8 Commercial Products 39718.9 Conclusions 398References 39919 Micro Energy Storage: Considerations 401Dan Steingart19.1 Introduction 40119.2 Boundary Conditions 40119.2.1 Microbatteries 40419.2.2 Supercapacitors 40519.3 Primary Energy Storage Approaches 40519.3.1 Volume-Constrained versus Conformally Demanding Approaches 40819.3.2 Caveat Emptor 40919.3.3 FutureWork and First-Order Problems 409References 41020 Thermoelectric Energy Harvesting in Aircraft 415Thomas Becker, Alexandros Elefsiniotis, andMichail E. Kiziroglou20.1 Introduction 41520.2 Aircraft Standardization 41620.3 AutonomousWireless Sensor Systems 41720.4 Thermoelectric Energy Harvesting in Aircraft 41920.4.1 Efficiency of a Thermoelectric Energy Harvesting Device 42020.4.2 StaticThermoelectric Energy Harvester 42120.4.3 Dynamic Thermoelectric Energy Harvester 42320.5 Design Considerations 42520.6 Applications 42720.6.1 StaticThermoelectric Harvester for Aircraft Seat Sensors 42720.6.2 The Dynamic Thermoelectric Harvesting Prototype 42820.6.3 Heat Storage Thermoelectric Harvester for Aircraft Strain Sensors 42820.6.4 Outlook 43020.7 Conclusions 432References 43321 Powering Pacemakers with Heartbeat Vibrations 435M. Amin Karami and Daniel J. Inman21.1 Introduction 43521.2 Design Specifications 43621.3 Estimation of Heartbeat Oscillations 43721.4 Linear Energy Harvesters 43821.5 Monostable Nonlinear Harvesters 44121.6 Bistable Harvesters 44621.7 Experimental Investigations 45021.8 Heart Motion Characterization 45021.9 Conclusions 456Acknowledgment 457References 457Index 459

Danick Briand obtained his PhD degree in the field of micro-chemical systems from the Institute of Microtechnology (IMT), University of Neuchatel, Switzerland, in 2001. He is currently a team leader at EPFL IMT Samlab in the field of EnviroMEMS, Energy and Enviromental MEMS. He has been awarded the Eurosensors Fellowship in 2010. He has been author or co-author on more than 150 papers published in scientific journals and conference proceedings. He is a member of several scientific and technical conference committees in the field of sensors and MEMS, participating also in the organization of workshop and conferences. His research interests in the field of sensors and microsystems include environmental and energy MEMS.Eric M. Yeatman has been a member of academic staff in Imperial College London since 1989, and Professor of Micro-Engineering since 2005. He is Deputy Head of the Department of Electrical and Electronic Engineering, and has published more than 160 papers and patents on optical devices and materials, and micro-electro-mechanical systems. In 2011 he was awarded the Royal Academy of Engineering Silver Medal. He has been principal or co-investigator on more than 20 research projects, and has acted as a design consultant for several international companies. His current research interests are in radio frequency and photonic MEMS devices, energy sources for wireless devices, and sensor networks.

"The book is loaded with ideas using a wide range of different energy harvesting methods with detailed explanations of the principles of each method and new materials being used to take advantage of the surrounding energy...Engineers interested in energy harvest­ing will find this book to be a very good resource for learning about new methods for parasitically powering low power electronic devices." (IEEE Electrical Insulation 17/03/2017)

• About the Volume Editors XVIIList of Contributors XIX1 Introduction to Micro Energy Harvesting 1Danick Briand, Eric Yeatman, and Shad Roundy1.1 Introduction to the Topic 11.2 Current Status and Trends 31.3 Book Content and Structure 42 Fundamentals of Mechanics and Dynamics 7Helios Vocca and Luca Gammaitoni2.1 Introduction 72.2 Strategies for Micro Vibration Energy Harvesting 82.2.1 Piezoelectric 92.2.2 Electromagnetic 102.2.3 Electrostatic 112.2.4 From Macro to Micro to Nano 112.3 Dynamical Models for Vibration Energy Harvesters 122.3.1 Stochastic Character of Ambient Vibrations 142.3.2 Linear Case 1: Piezoelectric Cantilever Generator 142.3.3 Linear Case 2: Electromagnetic Generator 152.3.4 Transfer Function 152.4 Beyond Linear Micro-Vibration Harvesting 162.4.1 Frequency Tuning 162.4.2 Multimodal Harvesting 172.4.3 Up-Conversion Techniques 172.5 Nonlinear Micro-Vibration Energy Harvesting 182.5.1 Bistable Oscillators: Cantilever 192.5.2 Bistable Oscillators: Buckled Beam 212.5.3 Monostable Oscillators 232.6 Conclusions 24Acknowledgments 24References 243 Electromechanical Transducers 27Adrien Badel, Fabien Formosa, andMickaël Lallart3.1 Introduction 273.2 Electromagnetic Transducers 273.2.1 Basic Principle 273.2.1.1 Induced Voltage 283.2.1.2 Self-Induction 283.2.1.3 Mechanical Aspect 293.2.2 Typical Architectures 303.2.2.1 Case Study 303.2.2.2 General Case 333.2.3 Energy Extraction Cycle 333.2.3.1 Resistive Cycle 343.2.3.2 Self-Inductance Cancelation 343.2.3.3 Cycle with Rectification 353.2.3.4 Active Cycle 363.2.4 Figures of Merit and Limitations 363.3 Piezoelectric Transducers 373.3.1 Basic Principles and Constitutive Equations 373.3.1.1 Physical Origin of Piezoelectricity in Ceramics and Crystals 373.3.1.2 Constitutive Equations 383.3.2 Typical Architectures for Energy Harvesting 393.3.2.1 Modeling 393.3.2.2 Application to Typical Configurations 403.3.3 Energy Extraction Cycles 413.3.3.1 Resistive Cycles 413.3.3.2 Cycles with Rectification 433.3.3.3 Active Cycles 433.3.3.4 Comparison 433.3.4 Maximal Power Density and Figure of Merit 443.4 Electrostatic Transducers 453.4.1 Basic Principles 453.4.1.1 Gauss’s Law 453.4.1.2 Capacitance C0 453.4.1.3 Electric Potential 463.4.1.4 Energy 463.4.1.5 Force 473.4.2 Design Parameters for a Capacitor 473.4.2.1 Architecture 473.4.2.2 Dielectric 483.4.3 Energy Extraction Cycles 483.4.3.1 Charge-Constrained Cycle 493.4.3.2 Voltage-Constrained Cycle 503.4.3.3 Electret Cycle 513.4.4 Limits 513.4.4.1 Parasitic Capacitors 513.4.4.2 Breakdown Voltage 533.4.4.3 Pull-In Force 533.5 Other Electromechanical Transduction Principles 533.5.1 Electrostrictive Materials 533.5.1.1 Physical Origin and Constitutive Equations 533.5.1.2 Energy Harvesting Strategies 543.5.2 Magnetostrictive Materials 553.5.2.1 Physical Origin 553.5.2.2 Constitutive Equations 563.6 Effect of the Vibration Energy Harvester Mechanical Structure 563.7 Summary 58References 594 Thermal Fundamentals 61Mathieu Francoeur4.1 Introduction 614.2 Fundamentals of Thermoelectric Power Generation 624.2.1 Overview of Nanoscale Heat Conduction and the Seebeck Effect 624.2.2 Heat Transfer Analysis ofThermoelectric Power Generation 644.3 Near-FieldThermal Radiation andThermophotovoltaic Power Generation 664.3.1 Introduction 664.3.2 Theoretical Framework: Fluctuational Electrodynamics 674.3.3 Introduction toThermophotovoltaic Power Generation and Physics of Near-Field Radiative Heat Transfer between Two Bulk Materials Separated by a Subwavelength Vacuum Gap 704.3.4 Nanoscale-Gap Thermophotovoltaic Power Generation 764.4 Conclusions 80Acknowledgments 80References 815 Power Conditioning for Energy Harvesting – Theory and Architecture 85Stephen G. Burrow and Paul D.Mitcheson5.1 Introduction 855.2 The Function of Power Conditioning 855.2.1 Interface to the Harvester 865.2.2 Circuits with Resistive Input Impedance 875.2.3 Circuits with Reactive Input Impedance 895.2.4 Circuits with Nonlinear Input Impedance 905.2.5 Peak Rectifiers 905.2.6 Piezoelectric Pre-biasing 925.2.7 Control 945.2.7.1 Voltage Regulation 945.2.7.2 Peak Power Controllers 965.2.8 System Architectures 975.2.8.1 Start-Up 975.2.9 Highly Dynamic Load Power 985.3 Summary 100References 1006 ThermoelectricMaterials for Energy Harvesting 103Andrew C.Miner6.1 Introduction 1036.2 Performance Considerations in Materials Selection: zT 1036.2.1 Properties of Chalcogenides (Group 16) 1066.2.2 Properties of Crystallogens (Group 14) 1066.2.3 Properties of Pnictides (Group 15) 1076.2.4 Properties of Skutterudites 1086.3 Influence of Scale on Material Selection and Synthesis 1106.3.1 Thermal Conductance Mismatch 1116.3.2 Domination of Electrical Contact Resistances 1126.3.3 Domination of Bypass Heat Flow 1136.3.4 Challenges inThermoelectric Property Measurement 1136.4 Low Dimensionality: Internal Micro/Nanostructure and Related Approaches 1146.5 Thermal Expansion and Its Role in Materials Selection 1156.6 Raw Material Cost Considerations 1166.7 Material Synthesis with Particular Relevance to Micro Energy Harvesting 1166.7.1 Electroplating, Electrophoresis, Dielectrophoresis 1176.7.2 Thin andThick Film Deposition 1186.8 Summary 118References 1197 Piezoelectric Materials for Energy Harvesting 123Emmanuel Defay, Sébastien Boisseau, and Ghislain Despesse7.1 Introduction 1237.2 What Is Piezoelectricity? 1237.3 Thermodynamics: the RightWay to Describe Piezoelectricity 1257.4 Material Figure of Merit: the Electromechanical Coupling Factor 1267.4.1 Special Considerations for Energy Harvesting 1287.5 Perovskite Materials 1297.5.1 Structure 1297.5.1.1 Ferroelectricity in Perovskites 1297.5.1.2 Piezoelectricity in Perovskites: Poling Required 1317.5.2 PZT Phase Diagram 1317.5.3 Ceramics 1327.5.3.1 Fabrication Process 1327.5.3.2 Typical Examples for Energy Harvesting 1347.5.4 Bulk Single Crystals 1357.5.4.1 Perovskites 1357.5.4.2 Energy Harvesting with Perovskites Bulk Single Crystals 1357.5.5 Polycrystalline PerovskitesThin Films 1367.5.5.1 Fabrication Processes 1367.5.5.2 Energy Harvesting with Poly-PZT Films 1367.5.6 Single-Crystal Thin Films 1377.5.6.1 Fabrication Process 1377.5.6.2 Energy Harvesting with SC Perovskite Films 1377.5.7 Lead-Free 1387.5.7.1 Energy Harvesting with Lead-Free Materials 1397.6 Wurtzites 1397.6.1 Structure 1397.6.2 Thin Films and Energy Harvesting 1407.6.3 Doping 1417.7 PVDFs 1417.7.1 Structure 1417.7.2 Synthesis 1437.7.3 Energy Harvesters with PVDF 1437.8 Nanomaterials 1437.9 Typical Values for the Main Piezoelectric Materials 1447.10 Summary 145References 1458 Electrostatic/Electret-Based Harvesters 149Yuji Suzuki8.1 Introduction 1498.2 Electrostatic/Electret Conversion Cycle 1498.3 Electrostatic/Electret Generator Models 1518.3.1 Configuration of Electrostatic/Electret Generator 1518.3.2 Electrode Design for Electrostatic/Electret Generator 1538.4 Electrostatic Generators 1568.4.1 Design and Fabrication Methods 1568.4.2 Generator Examples 1588.5 Electrets and Electret Generator Model 1608.5.1 Electrets 1608.5.2 Electret Materials 1618.5.3 Charging Technologies 1628.5.4 Electret Generator Model 1638.6 Electret Generators 1688.7 Summary 171References 1719 Electrodynamic Vibrational Energy Harvesting 175Shuo Cheng, Clemens Cepnik, and David P. Arnold9.1 Introduction 1759.2 Theoretical Background 1789.2.1 Energy Storage, Dissipation, and Conversion 1789.2.2 Electrodynamic Physics 1799.2.2.1 Faraday’s Law 1799.2.2.2 Lorentz Force 1809.2.3 Simplified Electrodynamic Equations 1809.3 Electrodynamic Harvester Architectures 1819.4 Modeling and Optimization 1839.4.1 Modeling 1849.4.1.1 Lumped Element Method 1849.4.1.2 Finite Element Method 1889.4.1.3 Combination of Lumped Element Model and Finite Element Model 1899.4.2 Optimization 1909.5 Design and Fabrication 1919.5.1 Design of Electrodynamic Harvesters 1929.5.2 Fabrication of Electrodynamic Harvesters 1949.6 Summary 196References 19710 Piezoelectric MEMS Energy Harvesters 201Jae Yeong Park10.1 Introduction 20110.1.1 The General Governing Equation 20210.1.2 Design Consideration 20310.2 Development of Piezoelectric MEMS Energy Harvesters 20410.2.1 Overview 20410.2.2 Fabrication Technologies 20510.2.3 Characterization 21110.2.3.1 Frequency Response 21110.2.3.2 Output Power of Piezoelectric MEMS Energy Harvesters 21110.3 Challenging Issues in Piezoelectric MEMS Energy Harvesters 21310.3.1 Output Power 21310.3.2 Frequency Response 21510.3.3 Piezoelectric Material 21710.4 Summary 218References 21811 Vibration Energy Harvesting fromWideband and Time-Varying Frequencies 223Lindsay M.Miller11.1 Introduction 223Contents XI11.1.1 Motivation 22311.1.2 Classification of Devices 22311.1.3 General Comments 22511.2 Active Schemes for Tunable Resonant Devices 22511.2.1 Stiffness Modification for Frequency Tuning 22611.2.1.1 Modify L 22611.2.1.2 Modify E 22711.2.1.3 Modify keff Using Axial Force 22711.2.1.4 Modify keff Using an External Spring 22911.2.1.5 Modify keff Using an Electrical External Spring 23111.2.2 Mass Modification for Frequency Tuning 23211.3 Passive Schemes for Tunable Resonant Devices 23211.3.1 Modify meff by Coupling Mass Position with Beam Excitation 23311.3.2 Modify keff by Coupling Axial Force with Centrifugal Force from Rotation 23411.3.3 Modify L by Using Centrifugal Force to Toggle Beam Clamp Position 23411.4 Wideband Devices 23511.4.1 Multimodal Designs 23611.4.2 Nonlinear Designs 23711.5 Summary and Future Research Directions 24011.5.1 Summary of Tunable andWideband Strategies 24011.5.2 Areas for Future Improvement in Tunable andWideband Strategies 24111.5.2.1 Tuning range and resolution 24111.5.2.2 Tuning sensitivity to driving vibrations 24211.5.2.3 System Size considerations 242References 24312 Micro Thermoelectric Generators 245Ingo Stark12.1 Introduction 24512.2 Classification of Micro Thermoelectric Generators 24712.3 General Considerations for MicroTEGs 25012.4 Micro Device Technologies 25212.4.1 Research and Development 25312.4.1.1 Electrodeposition 25312.4.1.2 Silicon-MEMS Technology 25312.4.1.3 CMOS-MEMS Technology 25412.4.1.4 Other 25512.4.2 Commercialized Micro Technologies 25712.4.2.1 Micropelt Technology 25712.4.2.2 Nextreme/Laird Technology 25812.4.2.3 Thermogen Technology 25912.5 Applications of Complete Systems 26012.5.1 Energy-Autonomous Sensor for Air Flow Temperature 26112.5.2 Wireless Pulse Oximeter SpO2 Sensor 26112.5.3 Intelligent Thermostatic Radiator Valve (iTRV) 26212.5.4 Wireless Power Generator Evaluation Kit 26312.5.5 Jacket-IntegratedWireless Temperature Sensor 26312.6 Summary 264References 26513 Micromachined Acoustic Energy Harvesters 271Stephen Horowitz and Mark Sheplak13.1 Introduction 27113.2 Historical Overview 27213.2.1 A Brief History 27213.2.2 Survey of Reported Performance 27413.3 Acoustics Background 27613.3.1 Principles and Concepts 27613.3.2 Fundamentals of Acoustics 27613.3.3 Challenges of Acoustic Energy Harvesting 27713.4 Electroacoustic Transduction 27713.4.1 Modeling 27813.4.1.1 Lumped Element Modeling (LEM) 27813.4.1.2 Equivalent Circuits 27913.4.1.3 Transduction 28013.4.1.4 Numerical Approaches 28113.4.2 Impedance Matching and Energy Focusing 28113.4.3 Transduction Methods 28113.4.3.1 Piezoelectric Transduction 28113.4.3.2 Electromagnetic Transduction 28213.4.3.3 Electrostatic Transduction 28213.4.3.4 Comparative Analysis 28313.4.4 Transduction Structures 28413.4.4.1 Structures for Impedance Matching 28413.4.4.2 Structures for Acoustical to Mechanical Transduction 28613.5 Fabrication Methods 28813.5.1 Materials 28813.5.2 Processes 28913.6 Testing and Characterization 28913.7 Summary 290Acknowledgments 290References 29014 Energy Harvesting from Fluid Flows 297Andrew S. Holmes14.1 Introduction 29714.2 Fundamental and Practical Limits 298Contents XIII14.3 MiniatureWind Turbines 30114.3.1 Scaling Effects in MiniatureWind Turbines 30214.3.1.1 Turbine Performance 30214.3.1.2 Generator and Bearing Losses 30514.4 Energy Harvesters Based on Flow Instability 30614.4.1 Vortex Shedding Devices 30714.4.2 Devices Based on Galloping and Flutter 31014.5 Performance Comparison 31614.6 Summary 317References 31715 Far-Field RF Energy Transfer and Harvesting 321Hubregt J. Visser and Ruud Vullers15.1 Introduction 32115.2 Nonradiative and Radiative (Far-Field) RF Energy Transfer 32215.2.1 Nonradiative Transfer 32215.2.2 Radiative Transfer 32315.2.3 Harvesting versus Transfer 32415.3 Receiving Rectifying Antenna 32615.3.1 Antenna–Rectifier Matching 32615.3.1.1 Voltage Boosting Technique 32715.3.1.2 Antenna Matched to Rectifier 32815.3.1.3 Antenna Not Matched to the Rectifier/Multiplier 32915.3.1.4 Consequences for the Rectifier and the Antenna Design 33015.4 Rectifier 33015.4.1 RF Input Impedance 33115.4.2 DC Output Voltage 33215.4.3 Antenna 33415.4.3.1 50 Ω Antenna 33515.4.3.2 Complex Conjugately Matched Antenna 33515.4.4 Rectenna Results 33615.4.5 Voltage Up-Conversion 33915.5 Transmission 34015.6 Examples and Future Perspectives 34115.7 Conclusions 344References 34416 Microfabricated Microbial Fuel Cells 347Hao Ren and Junseok Chae16.1 Introduction 34716.2 Fundamentals of MEMS MFC 34816.2.1 Operation Principle 34816.2.1.1 Structure 34816.2.1.2 Materials 35016.2.2 Critical Parameters for Testing 35016.2.2.1 Anode and Cathode Potential, the Total Cell Potential 35016.2.2.2 Open Circuit Voltage (EOCV) 35116.2.2.3 Areal/Volumetric Current Density and Areal/Volumetric Power Density 35116.2.2.4 Internal Resistance and Areal Resistivity 35216.2.2.5 Efficiency 35316.3 Prior Art MEMS MFCS 35416.4 FutureWork 35516.4.1 Reducing Areal Resistivity 35516.4.1.1 Applying Materials with High Surface-Area-to-Volume Ratio 35516.4.1.2 Mitigating Oxygen Intrusion 35816.4.2 Autonomous Running 35916.4.3 Elucidating the EET Mechanism 359References 35917 Micro Photovoltaic Module Energy Harvesting 363Shunpu Li ,WensiWang, NingningWang, Cian O’Mathuna, and Saibal Roy17.1 Introduction 36317.1.1 p-n Junction and Crystalline Si Solar Cells 36317.1.2 Amorphous Silicon Solar Cell 36617.1.3 CIGS and CdTe Solar Cell Development 36717.1.4 Polymer Solar Cell 37017.1.5 Dye-Sensitized Solar Cells (DSSC) 37317.2 Monolithically Integration of Solar Cells with IC 37517.3 Low-Power Micro Photovoltaic Systems 37617.3.1 Maximum Power Point Tracking 37617.3.2 Output Voltage Regulation 37917.3.3 Indoor-Light-PoweredWireless Sensor Networks – a Case Study 38017.4 Summary 382References 38318 Power Conditioning for Energy Harvesting – Case Studies and Commercial Products 385Paul D.Mitcheson and Stephen G. Burrow18.1 Introduction 38518.2 Submilliwatt Electromagnetic Harvester Circuit Example 38618.3 Single-Supply Pre-biasing for Piezoelectric Harvesters 38818.4 Ultra-Low-Power Rectifier and MPPT for Thermoelectric Harvesters 39218.5 Frequency Tuning of an Electromagnetic Harvester 39318.6 Examples of Converters for Ultra-Low-Output Transducers 39618.7 Power Processing for Electrostatic Devices 39718.8 Commercial Products 39718.9 Conclusions 398References 39919 Micro Energy Storage: Considerations 401Dan Steingart19.1 Introduction 40119.2 Boundary Conditions 40119.2.1 Microbatteries 40419.2.2 Supercapacitors 40519.3 Primary Energy Storage Approaches 40519.3.1 Volume-Constrained versus Conformally Demanding Approaches 40819.3.2 Caveat Emptor 40919.3.3 FutureWork and First-Order Problems 409References 41020 Thermoelectric Energy Harvesting in Aircraft 415Thomas Becker, Alexandros Elefsiniotis, andMichail E. Kiziroglou20.1 Introduction 41520.2 Aircraft Standardization 41620.3 AutonomousWireless Sensor Systems 41720.4 Thermoelectric Energy Harvesting in Aircraft 41920.4.1 Efficiency of a Thermoelectric Energy Harvesting Device 42020.4.2 StaticThermoelectric Energy Harvester 42120.4.3 Dynamic Thermoelectric Energy Harvester 42320.5 Design Considerations 42520.6 Applications 42720.6.1 StaticThermoelectric Harvester for Aircraft Seat Sensors 42720.6.2 The Dynamic Thermoelectric Harvesting Prototype 42820.6.3 Heat Storage Thermoelectric Harvester for Aircraft Strain Sensors 42820.6.4 Outlook 43020.7 Conclusions 432References 43321 Powering Pacemakers with Heartbeat Vibrations 435M. Amin Karami and Daniel J. Inman21.1 Introduction 43521.2 Design Specifications 43621.3 Estimation of Heartbeat Oscillations 43721.4 Linear Energy Harvesters 43821.5 Monostable Nonlinear Harvesters 44121.6 Bistable Harvesters 44621.7 Experimental Investigations 45021.8 Heart Motion Characterization 45021.9 Conclusions 456Acknowledgment 457References 457Index 459

Danick Briand obtained his PhD degree in the field of micro-chemical systems from the Institute of Microtechnology (IMT), University of Neuchatel, Switzerland, in 2001. He is currently a team leader at EPFL IMT Samlab in the field of EnviroMEMS, Energy and Enviromental MEMS. He has been awarded the Eurosensors Fellowship in 2010. He has been author or co-author on more than 150 papers published in scientific journals and conference proceedings. He is a member of several scientific and technical conference committees in the field of sensors and MEMS, participating also in the organization of workshop and conferences. His research interests in the field of sensors and microsystems include environmental and energy MEMS.Eric M. Yeatman has been a member of academic staff in Imperial College London since 1989, and Professor of Micro-Engineering since 2005. He is Deputy Head of the Department of Electrical and Electronic Engineering, and has published more than 160 papers and patents on optical devices and materials, and micro-electro-mechanical systems. In 2011 he was awarded the Royal Academy of Engineering Silver Medal. He has been principal or co-investigator on more than 20 research projects, and has acted as a design consultant for several international companies. His current research interests are in radio frequency and photonic MEMS devices, energy sources for wireless devices, and sensor networks.

"The book is loaded with ideas using a wide range of different energy harvesting methods with detailed explanations of the principles of each method and new materials being used to take advantage of the surrounding energy...Engineers interested in energy harvest­ing will find this book to be a very good resource for learning about new methods for parasitically powering low power electronic devices." (IEEE Electrical Insulation 17/03/2017)

• About the Volume Editors XVIIList of Contributors XIX1 Introduction to Micro Energy Harvesting 1Danick Briand, Eric Yeatman, and Shad Roundy1.1 Introduction to the Topic 11.2 Current Status and Trends 31.3 Book Content and Structure 42 Fundamentals of Mechanics and Dynamics 7Helios Vocca and Luca Gammaitoni2.1 Introduction 72.2 Strategies for Micro Vibration Energy Harvesting 82.2.1 Piezoelectric 92.2.2 Electromagnetic 102.2.3 Electrostatic 112.2.4 From Macro to Micro to Nano 112.3 Dynamical Models for Vibration Energy Harvesters 122.3.1 Stochastic Character of Ambient Vibrations 142.3.2 Linear Case 1: Piezoelectric Cantilever Generator 142.3.3 Linear Case 2: Electromagnetic Generator 152.3.4 Transfer Function 152.4 Beyond Linear Micro-Vibration Harvesting 162.4.1 Frequency Tuning 162.4.2 Multimodal Harvesting 172.4.3 Up-Conversion Techniques 172.5 Nonlinear Micro-Vibration Energy Harvesting 182.5.1 Bistable Oscillators: Cantilever 192.5.2 Bistable Oscillators: Buckled Beam 212.5.3 Monostable Oscillators 232.6 Conclusions 24Acknowledgments 24References 243 Electromechanical Transducers 27Adrien Badel, Fabien Formosa, andMickaël Lallart3.1 Introduction 273.2 Electromagnetic Transducers 273.2.1 Basic Principle 273.2.1.1 Induced Voltage 283.2.1.2 Self-Induction 283.2.1.3 Mechanical Aspect 293.2.2 Typical Architectures 303.2.2.1 Case Study 303.2.2.2 General Case 333.2.3 Energy Extraction Cycle 333.2.3.1 Resistive Cycle 343.2.3.2 Self-Inductance Cancelation 343.2.3.3 Cycle with Rectification 353.2.3.4 Active Cycle 363.2.4 Figures of Merit and Limitations 363.3 Piezoelectric Transducers 373.3.1 Basic Principles and Constitutive Equations 373.3.1.1 Physical Origin of Piezoelectricity in Ceramics and Crystals 373.3.1.2 Constitutive Equations 383.3.2 Typical Architectures for Energy Harvesting 393.3.2.1 Modeling 393.3.2.2 Application to Typical Configurations 403.3.3 Energy Extraction Cycles 413.3.3.1 Resistive Cycles 413.3.3.2 Cycles with Rectification 433.3.3.3 Active Cycles 433.3.3.4 Comparison 433.3.4 Maximal Power Density and Figure of Merit 443.4 Electrostatic Transducers 453.4.1 Basic Principles 453.4.1.1 Gauss’s Law 453.4.1.2 Capacitance C0 453.4.1.3 Electric Potential 463.4.1.4 Energy 463.4.1.5 Force 473.4.2 Design Parameters for a Capacitor 473.4.2.1 Architecture 473.4.2.2 Dielectric 483.4.3 Energy Extraction Cycles 483.4.3.1 Charge-Constrained Cycle 493.4.3.2 Voltage-Constrained Cycle 503.4.3.3 Electret Cycle 513.4.4 Limits 513.4.4.1 Parasitic Capacitors 513.4.4.2 Breakdown Voltage 533.4.4.3 Pull-In Force 533.5 Other Electromechanical Transduction Principles 533.5.1 Electrostrictive Materials 533.5.1.1 Physical Origin and Constitutive Equations 533.5.1.2 Energy Harvesting Strategies 543.5.2 Magnetostrictive Materials 553.5.2.1 Physical Origin 553.5.2.2 Constitutive Equations 563.6 Effect of the Vibration Energy Harvester Mechanical Structure 563.7 Summary 58References 594 Thermal Fundamentals 61Mathieu Francoeur4.1 Introduction 614.2 Fundamentals of Thermoelectric Power Generation 624.2.1 Overview of Nanoscale Heat Conduction and the Seebeck Effect 624.2.2 Heat Transfer Analysis ofThermoelectric Power Generation 644.3 Near-FieldThermal Radiation andThermophotovoltaic Power Generation 664.3.1 Introduction 664.3.2 Theoretical Framework: Fluctuational Electrodynamics 674.3.3 Introduction toThermophotovoltaic Power Generation and Physics of Near-Field Radiative Heat Transfer between Two Bulk Materials Separated by a Subwavelength Vacuum Gap 704.3.4 Nanoscale-Gap Thermophotovoltaic Power Generation 764.4 Conclusions 80Acknowledgments 80References 815 Power Conditioning for Energy Harvesting – Theory and Architecture 85Stephen G. Burrow and Paul D.Mitcheson5.1 Introduction 855.2 The Function of Power Conditioning 855.2.1 Interface to the Harvester 865.2.2 Circuits with Resistive Input Impedance 875.2.3 Circuits with Reactive Input Impedance 895.2.4 Circuits with Nonlinear Input Impedance 905.2.5 Peak Rectifiers 905.2.6 Piezoelectric Pre-biasing 925.2.7 Control 945.2.7.1 Voltage Regulation 945.2.7.2 Peak Power Controllers 965.2.8 System Architectures 975.2.8.1 Start-Up 975.2.9 Highly Dynamic Load Power 985.3 Summary 100References 1006 ThermoelectricMaterials for Energy Harvesting 103Andrew C.Miner6.1 Introduction 1036.2 Performance Considerations in Materials Selection: zT 1036.2.1 Properties of Chalcogenides (Group 16) 1066.2.2 Properties of Crystallogens (Group 14) 1066.2.3 Properties of Pnictides (Group 15) 1076.2.4 Properties of Skutterudites 1086.3 Influence of Scale on Material Selection and Synthesis 1106.3.1 Thermal Conductance Mismatch 1116.3.2 Domination of Electrical Contact Resistances 1126.3.3 Domination of Bypass Heat Flow 1136.3.4 Challenges inThermoelectric Property Measurement 1136.4 Low Dimensionality: Internal Micro/Nanostructure and Related Approaches 1146.5 Thermal Expansion and Its Role in Materials Selection 1156.6 Raw Material Cost Considerations 1166.7 Material Synthesis with Particular Relevance to Micro Energy Harvesting 1166.7.1 Electroplating, Electrophoresis, Dielectrophoresis 1176.7.2 Thin andThick Film Deposition 1186.8 Summary 118References 1197 Piezoelectric Materials for Energy Harvesting 123Emmanuel Defay, Sébastien Boisseau, and Ghislain Despesse7.1 Introduction 1237.2 What Is Piezoelectricity? 1237.3 Thermodynamics: the RightWay to Describe Piezoelectricity 1257.4 Material Figure of Merit: the Electromechanical Coupling Factor 1267.4.1 Special Considerations for Energy Harvesting 1287.5 Perovskite Materials 1297.5.1 Structure 1297.5.1.1 Ferroelectricity in Perovskites 1297.5.1.2 Piezoelectricity in Perovskites: Poling Required 1317.5.2 PZT Phase Diagram 1317.5.3 Ceramics 1327.5.3.1 Fabrication Process 1327.5.3.2 Typical Examples for Energy Harvesting 1347.5.4 Bulk Single Crystals 1357.5.4.1 Perovskites 1357.5.4.2 Energy Harvesting with Perovskites Bulk Single Crystals 1357.5.5 Polycrystalline PerovskitesThin Films 1367.5.5.1 Fabrication Processes 1367.5.5.2 Energy Harvesting with Poly-PZT Films 1367.5.6 Single-Crystal Thin Films 1377.5.6.1 Fabrication Process 1377.5.6.2 Energy Harvesting with SC Perovskite Films 1377.5.7 Lead-Free 1387.5.7.1 Energy Harvesting with Lead-Free Materials 1397.6 Wurtzites 1397.6.1 Structure 1397.6.2 Thin Films and Energy Harvesting 1407.6.3 Doping 1417.7 PVDFs 1417.7.1 Structure 1417.7.2 Synthesis 1437.7.3 Energy Harvesters with PVDF 1437.8 Nanomaterials 1437.9 Typical Values for the Main Piezoelectric Materials 1447.10 Summary 145References 1458 Electrostatic/Electret-Based Harvesters 149Yuji Suzuki8.1 Introduction 1498.2 Electrostatic/Electret Conversion Cycle 1498.3 Electrostatic/Electret Generator Models 1518.3.1 Configuration of Electrostatic/Electret Generator 1518.3.2 Electrode Design for Electrostatic/Electret Generator 1538.4 Electrostatic Generators 1568.4.1 Design and Fabrication Methods 1568.4.2 Generator Examples 1588.5 Electrets and Electret Generator Model 1608.5.1 Electrets 1608.5.2 Electret Materials 1618.5.3 Charging Technologies 1628.5.4 Electret Generator Model 1638.6 Electret Generators 1688.7 Summary 171References 1719 Electrodynamic Vibrational Energy Harvesting 175Shuo Cheng, Clemens Cepnik, and David P. Arnold9.1 Introduction 1759.2 Theoretical Background 1789.2.1 Energy Storage, Dissipation, and Conversion 1789.2.2 Electrodynamic Physics 1799.2.2.1 Faraday’s Law 1799.2.2.2 Lorentz Force 1809.2.3 Simplified Electrodynamic Equations 1809.3 Electrodynamic Harvester Architectures 1819.4 Modeling and Optimization 1839.4.1 Modeling 1849.4.1.1 Lumped Element Method 1849.4.1.2 Finite Element Method 1889.4.1.3 Combination of Lumped Element Model and Finite Element Model 1899.4.2 Optimization 1909.5 Design and Fabrication 1919.5.1 Design of Electrodynamic Harvesters 1929.5.2 Fabrication of Electrodynamic Harvesters 1949.6 Summary 196References 19710 Piezoelectric MEMS Energy Harvesters 201Jae Yeong Park10.1 Introduction 20110.1.1 The General Governing Equation 20210.1.2 Design Consideration 20310.2 Development of Piezoelectric MEMS Energy Harvesters 20410.2.1 Overview 20410.2.2 Fabrication Technologies 20510.2.3 Characterization 21110.2.3.1 Frequency Response 21110.2.3.2 Output Power of Piezoelectric MEMS Energy Harvesters 21110.3 Challenging Issues in Piezoelectric MEMS Energy Harvesters 21310.3.1 Output Power 21310.3.2 Frequency Response 21510.3.3 Piezoelectric Material 21710.4 Summary 218References 21811 Vibration Energy Harvesting fromWideband and Time-Varying Frequencies 223Lindsay M.Miller11.1 Introduction 223Contents XI11.1.1 Motivation 22311.1.2 Classification of Devices 22311.1.3 General Comments 22511.2 Active Schemes for Tunable Resonant Devices 22511.2.1 Stiffness Modification for Frequency Tuning 22611.2.1.1 Modify L 22611.2.1.2 Modify E 22711.2.1.3 Modify keff Using Axial Force 22711.2.1.4 Modify keff Using an External Spring 22911.2.1.5 Modify keff Using an Electrical External Spring 23111.2.2 Mass Modification for Frequency Tuning 23211.3 Passive Schemes for Tunable Resonant Devices 23211.3.1 Modify meff by Coupling Mass Position with Beam Excitation 23311.3.2 Modify keff by Coupling Axial Force with Centrifugal Force from Rotation 23411.3.3 Modify L by Using Centrifugal Force to Toggle Beam Clamp Position 23411.4 Wideband Devices 23511.4.1 Multimodal Designs 23611.4.2 Nonlinear Designs 23711.5 Summary and Future Research Directions 24011.5.1 Summary of Tunable andWideband Strategies 24011.5.2 Areas for Future Improvement in Tunable andWideband Strategies 24111.5.2.1 Tuning range and resolution 24111.5.2.2 Tuning sensitivity to driving vibrations 24211.5.2.3 System Size considerations 242References 24312 Micro Thermoelectric Generators 245Ingo Stark12.1 Introduction 24512.2 Classification of Micro Thermoelectric Generators 24712.3 General Considerations for MicroTEGs 25012.4 Micro Device Technologies 25212.4.1 Research and Development 25312.4.1.1 Electrodeposition 25312.4.1.2 Silicon-MEMS Technology 25312.4.1.3 CMOS-MEMS Technology 25412.4.1.4 Other 25512.4.2 Commercialized Micro Technologies 25712.4.2.1 Micropelt Technology 25712.4.2.2 Nextreme/Laird Technology 25812.4.2.3 Thermogen Technology 25912.5 Applications of Complete Systems 26012.5.1 Energy-Autonomous Sensor for Air Flow Temperature 26112.5.2 Wireless Pulse Oximeter SpO2 Sensor 26112.5.3 Intelligent Thermostatic Radiator Valve (iTRV) 26212.5.4 Wireless Power Generator Evaluation Kit 26312.5.5 Jacket-IntegratedWireless Temperature Sensor 26312.6 Summary 264References 26513 Micromachined Acoustic Energy Harvesters 271Stephen Horowitz and Mark Sheplak13.1 Introduction 27113.2 Historical Overview 27213.2.1 A Brief History 27213.2.2 Survey of Reported Performance 27413.3 Acoustics Background 27613.3.1 Principles and Concepts 27613.3.2 Fundamentals of Acoustics 27613.3.3 Challenges of Acoustic Energy Harvesting 27713.4 Electroacoustic Transduction 27713.4.1 Modeling 27813.4.1.1 Lumped Element Modeling (LEM) 27813.4.1.2 Equivalent Circuits 27913.4.1.3 Transduction 28013.4.1.4 Numerical Approaches 28113.4.2 Impedance Matching and Energy Focusing 28113.4.3 Transduction Methods 28113.4.3.1 Piezoelectric Transduction 28113.4.3.2 Electromagnetic Transduction 28213.4.3.3 Electrostatic Transduction 28213.4.3.4 Comparative Analysis 28313.4.4 Transduction Structures 28413.4.4.1 Structures for Impedance Matching 28413.4.4.2 Structures for Acoustical to Mechanical Transduction 28613.5 Fabrication Methods 28813.5.1 Materials 28813.5.2 Processes 28913.6 Testing and Characterization 28913.7 Summary 290Acknowledgments 290References 29014 Energy Harvesting from Fluid Flows 297Andrew S. Holmes14.1 Introduction 29714.2 Fundamental and Practical Limits 298Contents XIII14.3 MiniatureWind Turbines 30114.3.1 Scaling Effects in MiniatureWind Turbines 30214.3.1.1 Turbine Performance 30214.3.1.2 Generator and Bearing Losses 30514.4 Energy Harvesters Based on Flow Instability 30614.4.1 Vortex Shedding Devices 30714.4.2 Devices Based on Galloping and Flutter 31014.5 Performance Comparison 31614.6 Summary 317References 31715 Far-Field RF Energy Transfer and Harvesting 321Hubregt J. Visser and Ruud Vullers15.1 Introduction 32115.2 Nonradiative and Radiative (Far-Field) RF Energy Transfer 32215.2.1 Nonradiative Transfer 32215.2.2 Radiative Transfer 32315.2.3 Harvesting versus Transfer 32415.3 Receiving Rectifying Antenna 32615.3.1 Antenna–Rectifier Matching 32615.3.1.1 Voltage Boosting Technique 32715.3.1.2 Antenna Matched to Rectifier 32815.3.1.3 Antenna Not Matched to the Rectifier/Multiplier 32915.3.1.4 Consequences for the Rectifier and the Antenna Design 33015.4 Rectifier 33015.4.1 RF Input Impedance 33115.4.2 DC Output Voltage 33215.4.3 Antenna 33415.4.3.1 50 Ω Antenna 33515.4.3.2 Complex Conjugately Matched Antenna 33515.4.4 Rectenna Results 33615.4.5 Voltage Up-Conversion 33915.5 Transmission 34015.6 Examples and Future Perspectives 34115.7 Conclusions 344References 34416 Microfabricated Microbial Fuel Cells 347Hao Ren and Junseok Chae16.1 Introduction 34716.2 Fundamentals of MEMS MFC 34816.2.1 Operation Principle 34816.2.1.1 Structure 34816.2.1.2 Materials 35016.2.2 Critical Parameters for Testing 35016.2.2.1 Anode and Cathode Potential, the Total Cell Potential 35016.2.2.2 Open Circuit Voltage (EOCV) 35116.2.2.3 Areal/Volumetric Current Density and Areal/Volumetric Power Density 35116.2.2.4 Internal Resistance and Areal Resistivity 35216.2.2.5 Efficiency 35316.3 Prior Art MEMS MFCS 35416.4 FutureWork 35516.4.1 Reducing Areal Resistivity 35516.4.1.1 Applying Materials with High Surface-Area-to-Volume Ratio 35516.4.1.2 Mitigating Oxygen Intrusion 35816.4.2 Autonomous Running 35916.4.3 Elucidating the EET Mechanism 359References 35917 Micro Photovoltaic Module Energy Harvesting 363Shunpu Li ,WensiWang, NingningWang, Cian O’Mathuna, and Saibal Roy17.1 Introduction 36317.1.1 p-n Junction and Crystalline Si Solar Cells 36317.1.2 Amorphous Silicon Solar Cell 36617.1.3 CIGS and CdTe Solar Cell Development 36717.1.4 Polymer Solar Cell 37017.1.5 Dye-Sensitized Solar Cells (DSSC) 37317.2 Monolithically Integration of Solar Cells with IC 37517.3 Low-Power Micro Photovoltaic Systems 37617.3.1 Maximum Power Point Tracking 37617.3.2 Output Voltage Regulation 37917.3.3 Indoor-Light-PoweredWireless Sensor Networks – a Case Study 38017.4 Summary 382References 38318 Power Conditioning for Energy Harvesting – Case Studies and Commercial Products 385Paul D.Mitcheson and Stephen G. Burrow18.1 Introduction 38518.2 Submilliwatt Electromagnetic Harvester Circuit Example 38618.3 Single-Supply Pre-biasing for Piezoelectric Harvesters 38818.4 Ultra-Low-Power Rectifier and MPPT for Thermoelectric Harvesters 39218.5 Frequency Tuning of an Electromagnetic Harvester 39318.6 Examples of Converters for Ultra-Low-Output Transducers 39618.7 Power Processing for Electrostatic Devices 39718.8 Commercial Products 39718.9 Conclusions 398References 39919 Micro Energy Storage: Considerations 401Dan Steingart19.1 Introduction 40119.2 Boundary Conditions 40119.2.1 Microbatteries 40419.2.2 Supercapacitors 40519.3 Primary Energy Storage Approaches 40519.3.1 Volume-Constrained versus Conformally Demanding Approaches 40819.3.2 Caveat Emptor 40919.3.3 FutureWork and First-Order Problems 409References 41020 Thermoelectric Energy Harvesting in Aircraft 415Thomas Becker, Alexandros Elefsiniotis, andMichail E. Kiziroglou20.1 Introduction 41520.2 Aircraft Standardization 41620.3 AutonomousWireless Sensor Systems 41720.4 Thermoelectric Energy Harvesting in Aircraft 41920.4.1 Efficiency of a Thermoelectric Energy Harvesting Device 42020.4.2 StaticThermoelectric Energy Harvester 42120.4.3 Dynamic Thermoelectric Energy Harvester 42320.5 Design Considerations 42520.6 Applications 42720.6.1 StaticThermoelectric Harvester for Aircraft Seat Sensors 42720.6.2 The Dynamic Thermoelectric Harvesting Prototype 42820.6.3 Heat Storage Thermoelectric Harvester for Aircraft Strain Sensors 42820.6.4 Outlook 43020.7 Conclusions 432References 43321 Powering Pacemakers with Heartbeat Vibrations 435M. Amin Karami and Daniel J. Inman21.1 Introduction 43521.2 Design Specifications 43621.3 Estimation of Heartbeat Oscillations 43721.4 Linear Energy Harvesters 43821.5 Monostable Nonlinear Harvesters 44121.6 Bistable Harvesters 44621.7 Experimental Investigations 45021.8 Heart Motion Characterization 45021.9 Conclusions 456Acknowledgment 457References 457Index 459