Foreword xi Preface xiii Acknowledgment xv 1 Introduction: Toward Biomedical Applications 1 1.1 Biomedical Devices for Healthcare 1 1.1.1 Wearable Devices 3 1.1.2 Implantable Devices 6 1.2 Wireless Date Telemetry and Powering for Biomedical Devices 8 1.2.1 Wireless Data Telemetry for Biomedical Devices 8 1.2.2 Wireless Power Transmission for Biomedical Devices 12 1.3 Overview of Book 13 2 Miniaturized Wideband and Multiband Implantable Antennas 17 2.1 Introduction 17 2.2 Miniaturization Methods for Implantable Antenna Design 18 2.2.1 Use of High-permittivity Dielectric Substrate/Superstrate 18 2.2.2 Use of Planar Inverted-F Antenna Structure 20 2.2.3 Lengthening the Current Path of the Radiator 22 2.2.4 Loading Technique for Impedance Matching 24 2.2.5 Choosing Higher Operating Frequency 26 2.3 Wideband Miniaturized Implantable Antenna 28 2.3.1 Introducing Adjacent Resonant Frequency Points 28 2.3.1.1 Linear Wire Antenna 28 2.3.1.2 Slot Antenna 32 2.3.1.3 Loop Antenna 34 2.3.1.4 Microstrip Patch Antenna 34 2.3.2 Multiple Resonance and Wideband Impedance Matching 35 2.3.3 Advanced Technology for Detuning Problem 49 2.4 Multiband Miniaturized Implantable Antennas 50 2.4.1 Compact PIFAWith Multi-current Patch 50 2.4.2 Open-end Slots on Ground 54 2.4.3 Single-layer Design 55 2.5 Conclusions 61 3 Polarization Design for Implantable Antennas 67 3.1 Introduction 67 3.2 Compact Microstrip Patch Antenna for CP-implantable Antenna Design 68 3.2.1 Capacitively-loaded CP-implantable Patch Antenna 68 3.2.1.1 An Implantable Microstrip Patch Antenna with a Center Square Slot 68 3.2.1.2 Compact-implantable CP Patch Antenna with Capacitive Loading 71 3.2.1.3 Communication Link Study of the CP-implantable Patch Antenna 73 3.2.1.4 Sensitivity Evaluation of the Implantable CP Patch Antenna 75 3.2.2 Miniaturized Circularly Polarized-implantable Annular-ring Antenna 79 3.3 Wide AR Bandwidth-implantable Antenna 83 3.3.1 Miniaturized CP-implantable Loop Antenna 83 3.3.1.1 Configuration of the CP-implantable Loop Antenna 83 3.3.1.2 Principle of the CP-implantable Loop Antenna 86 3.3.1.3 Antenna Measurement and Discussions 88 3.3.1.4 Communication Link of the Implantable CP Loop Antennas 90 3.3.2 Ground Radiation CP-implantable Antenna 91 3.4 Application Base Design of CP-implantable Antenna -- Capsule Endoscopy 97 3.4.1 Axial-mode Multilayer Helical Antenna 97 3.4.1.1 Antenna Structure 99 3.4.1.2 Conformal Capsule Antenna Design Including Biocompatibility Shell Consideration 101 3.4.1.3 Wireless Capsule Endoscope System in a Human Body 103 3.4.1.4 In Vitro Testing and Discussions 108 3.4.2 Conformal CP Antenna for Wireless Capsule Endoscope Systems 112 3.4.2.1 Antenna Layout and Simulation Phantom 112 3.4.2.2 Mechanism of CP Operation 114 3.4.2.3 Results and Discussion 115 3.5 In Vivo Testing of Circularly Polarized-implantable Antennas 118 3.5.1 In Vivo Testing Configuration 118 3.5.2 Measured Reflection Coefficient 119 3.5.3 Analysis of the Results and Discussions 120 3.6 Conclusions 122 4 Differential-fed Implantable Antennas 129 4.1 Introduction 129 4.2 Dual-band Implantable Antenna for Neural Recording 130 4.2.1 Differential Reflection Coefficient Characterization 130 4.2.2 Antenna Design and Operating Principle 131 4.2.3 Measurement and Discussions 134 4.2.4 Communication Link Study 136 4.3 Integrated On-chip Antenna in 0.18μm CMOS Technology 137 4.3.1 System Requirement and Antenna Design 139 4.3.2 Chip-to-SMA Transition Design and Measurement 142 4.4 Dual-band Implantable Antenna for Capsule Systems 146 4.4.1 Planar-implantable Antenna Design 146 4.4.2 Conformal Capsule Design 149 4.4.3 Coating and In Vitro Measurement 153 4.5 Miniaturized Differentially Fed Dual-band Implantable Antenna 154 4.5.1 Miniaturized Dual-band Antenna Design 155 4.5.2 Parametric Analysis and Measurement 158 4.5.2.1 The Effect of the Shorting Strip 158 4.5.2.2 The Effect of the Length of L-shaped Arms 158 4.5.2.3 Measurement 159 4.6 Differentially Fed Antenna With Complex Input Impedance for Capsule Systems 160 4.6.1 Antenna Geometry 161 4.6.2 Operating Principle 162 4.6.2.1 Equivalent Circuit 163 4.6.2.2 Parametric Study 164 4.6.2.3 Comparison With T-Match 166 4.6.3 Experiment 169 4.7 Conclusions 172 5 Wearable Antennas for On-/Off-Body Communications 177 5.1 Introduction 177 5.2 ExploringWearable Antennas: Design and Fabrication Techniques 179 5.2.1 Typical Designs ofWearable Antennas 179 5.2.2 Variation of Antenna Characteristics and Design Considerations 181 5.2.3 AMC-Backed Near-EndfireWearable Antenna 182 5.3 Latex Substrate and Screen-Printing forWearable Antennas Fabrication 183 5.4 AMC-backed Endfire Antenna 184 5.4.1 Bidirectional Yagi Antenna for Endfire Radiation 184 5.4.2 Near-Endfire Yagi Antenna Backed by SAMC 184 5.4.3 Near-Endfire Yagi Antenna Backed by DAMC 187 5.5 Simulations of the Antennas in Free Space 189 5.5.1 Return Loss 189 5.5.2 Radiation Patterns 189 5.5.3 Gain 190 5.6 Simulations of the Antennas on Human Body 191 5.6.1 Frequency Detuning 191 5.6.2 SAR and Antenna Efficiency 192 5.6.3 Radiation Patterns on A Human Body 194 5.7 Antenna Performance Under Deformation 195 5.8 Experiment 198 5.8.1 Return Loss 198 5.8.2 Radiation Pattern Measurement 198 5.8.3 Gain Measurement 201 5.9 Conclusion 201 6 Investigation and Modeling of Capacitive Human Body Communication 205 6.1 Introduction 205 6.2 Galvanic and Capacitive Coupling HBC 206 6.3 Capacitive HBC 207 6.3.1 Experimental Characterizations 207 6.3.2 Numerical Models 211 6.3.3 Circuit Models of Capacitive HBC 212 6.3.4 Theoretical Analysis 212 6.4 Investigation and Modeling of Capacitive HBC 214 6.4.1 Measurement Setup and Results 214 6.4.2 Simulation Setup and Results 220 6.4.3 Equivalent Circuit Model 226 6.5 Conclusions: Other Design Considerations of HBC Systems 230 6.5.1 Channel Characteristics 231 6.5.2 Modulation and Communication Performance 232 6.5.3 Systems and Application Examples 232 7 Near-field Wireless Power Transfer for Biomedical Applications 237 7.1 Introduction 237 7.2 Resonant InductiveWireless Power Transfer (IWPT) and IWPT Topologies 238 7.2.1 Resonances in IWPT 238 7.2.2 Resonant IWPT Topologies 242 7.2.3 Power Transfer Efficiency 242 7.2.4 Experimental Verification 244 7.2.5 Limitations of the Resonance Tuning 245 7.3 IWPT Topology Selection Strategies 247 7.3.1 For Applications With a Fixed Load 247 7.3.2 For Applications With a Variable Load 249 7.3.3 Optimal Operating Frequency 251 7.3.4 Upper Limit on Power Transfer Efficiency 252 7.4 CapacitiveWireless Power Transfer (CWPT) 254 7.4.1 NCC Link Modeling 256 7.4.1.1 Tissue Model 257 7.4.1.2 Tissue Loss 258 7.4.1.3 Conductor Loss (RC) 260 7.4.1.4 Self-inductance 260 7.4.1.5 Equivalent Capacitance 260 7.4.1.6 Return Loss 261 7.4.1.7 Power Transfer Efficiency 261 7.4.1.8 Power Transfer Limit 262 7.4.2 Full-wave Simulation 264 7.4.3 Optimal Link Design 266 7.5 CWPT: Experiments in Nonhuman Primate Cadaver 267 7.5.1 Study on Power Transfer Efficiency 267 7.5.2 Flexion Study 269 7.6 Summary 270 8 Far-field Wireless Power Transmission for Biomedical Application 275 8.1 Introduction 275 8.2 Far-Field EM Coupling 275 8.2.1 Power Transfer Efficiency 277 8.2.2 Link Design 278 8.2.3 Challenges and Solutions 279 8.3 Enhanced Far-field WPT Link for Implants 280 8.3.1 Safety Considerations for Far-field Wireless Power Transmission 280 8.3.2 Implantable Rectenna Design 281 8.3.2.1 Implantable Antenna Configuration 281 8.3.2.2 Wireless Power Link Study 284 8.3.2.3 Safety Concerns 285 8.3.2.4 Method to Enhance the Received Power 287 8.3.2.5 Wireless Power Link With the Parasitic Patch 288 8.3.3 Measurement and Discussion 290 8.3.3.1 Rectifier Circuit Design 291 8.3.3.2 Integration Solution of the Implantable Rectenna 294 8.3.3.3 Measurement Setup 295 8.4 WPT Antenna Misalignment: An Antenna Alignment Method Using Intermodulation 297 8.4.1 Operation Mechanism 298 8.4.1.1 PCE Enhancement and Intermodulation Generation 298 8.4.1.2 Relation Between Intermodulation and Misalignments 300 8.4.2 Miniaturized IMD Rectenna Design With NRIC Link 300 8.4.2.1 Miniaturized Rectifier With Intermodulation Readout 300 8.4.2.2 IMD Antenna CodesignedWith Rectifier Circuit 302 8.4.2.3 NRIC Link Establishment 304 8.4.3 Experimental Validation 306 8.4.3.1 Experimental Setup 306 8.4.3.2 Results and Discussion 308 8.5 Summary 309 9 System Design Examples: Peripheral Nerve Implants and Neurostimulators 313 9.1 Introduction 313 9.2 Wireless Powering and Telemetry for Peripheral Nerve Implants 314 9.2.1 Peripheral Nerve Prostheses 314 9.2.1.1 Stimulator Implant 314 9.2.1.2 Neural Recording 314 9.2.1.3 Wireless Power Delivery and Telemetry Requirements 316 9.2.2 Wireless Platform for Peripheral Nerve Implants 317 9.2.2.1 Wireless Platform for Stimulator Implant 317 9.2.2.2 Wireless Platform for Recording Implant 319 9.2.3 Design and Experiments 319 9.2.3.1 Power Transfer Characteristics in Tissue Environments 320 9.2.3.2 Power Transfer Link for Peripheral Nerve Implants 323 9.2.3.3 Stimulator Implant Experiment 324 9.2.4 Safety 328 9.2.4.1 Biosafety 328 9.2.4.2 Electrical Safety 328 9.2.5 Near-field Resonant Inductive-coupling Link (NRIC) Versus Near-field Capacitive-coupling Link (NCC) 328 9.3 Co-matching Solution for Neurostimulator Narrow Band Antenna 330 9.3.1 Co-matching Antenna Operating Mode 332 9.3.2 Antenna Property in Body Phantom 334 9.3.3 Co-matching Circuit Design 336 9.3.4 Fabrication Processing of the Proposed Antenna 338 9.3.5 Reflection Coefficient and Impedance Measurement 339 9.3.6 Radiation Performance 340 9.4 Reconfigurable Antenna for Neurostimulator 343 9.4.1 Tuning Principle 344 9.4.2 Antenna Configuration and Design Procedures 344 9.4.3 Antenna Manufacturing and Measurement Setup 347 9.4.4 System Design 348 9.4.5 Antenna Tuning and Optimized RF Link 349 9.5 Summary 352 References 352 Index 357

Join the cutting edge of biomedical technology with this essential reference The role of wireless communications in biomedical technology is a significant one. Wireless and antenna-driven communication between telemetry components now forms the basis of cardiac pacemakers and defibrillators, cochlear implants, glucose readers, and more. As wireless technology continues to advance and miniaturization progresses, it’s more essential than ever that biomedical research and development incorporate the latest technology. Antennas and Wireless Power Transfer Methods for Biomedical Applications provides a comprehensive introduction to wireless technology and its incorporation into the biomedical field. Beginning with an introduction to recent developments in antenna and wireless technology, it analyzes the major wireless systems currently available and their biomedical applications, actual and potential. The result is an essential guide to technologies that have already improved patient outcomes and increased life expectancies worldwide. Readers will also find: Authored by internationally renowned researchers of wireless technologies Detailed analysis of CP implantable antennas, wearable antennas, near-field wireless power, and more Up to 100 figures that supplement the text Antennas and Wireless Power Transfer Methods for Biomedical Applications is a valuable introduction for biomedical researchers and biomedical engineers, as well as for research and development professionals in the medical device industry.