Preface ........................................................ xi
CHAPTER 1
Introduction to Body-Centric Wireless Communications ............ 1
1.1 What Are Body-Centric Communications Systems? .............. 1
1.2 Off-Body to On-Body Communications ......................... 5
1.3 On-Body Communications ..................................... 5
1.4 Medical Implants and Sensor Networks ....................... 6
1.5 Layout of the Book ......................................... 7
References ...................................................... 8
CHAPTER 2
Electromagnetic Properties and Modeling of the Human Body ...... 11
2.1 Electromagnetic Characteristics of Human Tissues .......... 11
2.2 Physical Body Phantoms .................................... 12
2.2.1 Liquid Phantoms .................................... 14
2.2.2 Semisolid (Gel) or Solid (Wet) Phantoms ............ 17
2.2.3 Solid (Dry) Phantoms ............................... 17
2.2.4 Examples of Physical Phantoms ...................... 18
2.3 Numerical Phantoms ........................................ 20
2.3.1 Theoretical Phantoms ............................... 21
2.3.2 Voxel Phantoms ..................................... 21
2.4 Numerical Modeling Techniques for Body-Centric Wireless
Communications ............................................ 22
2.4.1 Introduction of Numerical Techniques ............... 22
2.4.2 On-Body Radio Channel Modeling ..................... 27
References ..................................................... 34
CHAPTER 3
Antennas and Propagation for On-Body Communication at
Microwave Frequencies .......................................... 39
3.1 Introduction .............................................. 39
3.2 On-Body Channel Measurement and Modeling .................. 41
3.3 Antenna Design ............................................ 51
3.3.1 Comparison of Antenna Types ........................ 52
3.3.2 Antenna Match and Efficiency ....................... 52
3.4 Simulation and Modeling ................................... 56
3.5 Systems Modeling .......................................... 60
3.6 Conclusions ............................................... 62
Acknowledgments ................................................ 63
References ..................................................... 63
CHAPTER 4
Transmission Mechanism of Wearable Devices Using the Human
Body as a Transmission Channel ................................. 65
4.1 Introduction to Communications Using Circuits in Direct
Contact with the Human Body ............................... 65
4.2 Numerical Analysis and Equivalent Circuit Models .......... 68
4.2.1 Whole Body Models .................................. 68
4.2.2 Arm Models ......................................... 70
4.2.3 Effective Electrode Structure ...................... 73
4.2.4 Equivalent Circuit Models .......................... 74
4.3 Experiments Using Human Phantom ........................... 76
4.3.1 Measurement of the Signal Distributions ............ 76
4.3.2 Comparison Between Measurement and Calculation ..... 78
4.3.3 Electric Field Distributions in and Around the
Arm ................................................ 82
4.3.4 Received Signal Voltage of the Receiver ............ 83
4.4 Investigation of the Dominant Signal Transmission Path .... 86
4.4.1 Calculation Model .................................. 86
4.4.2 Electric Field Distributions and Received Signal
Voltages ........................................... 87
4.5 Conclusions ............................................... 89
References ..................................................... 91
CHAPTER 5
Body-Centric UWB Communications ................................ 93
5.1 Overview .................................................. 93
5.2 Antennas .................................................. 94
5.2.1 Design and Analysis ................................ 94
5.2.2 Measurements ...................................... 109
5.2.3 Concluding Remarks ................................ 111
5.3 Channel Simulation and Measurement Methodology ........... 111
5.3.1 Simulation of the Radio Propagation in Body-
Centric Communication Scenarios ................... 111
5.3.2 Measurement of the Radio Propagation in Body-
Centric Communication Scenarios ................... 112
5.3.3 Concluding Remarks ................................ 120
5.4 Channel Characterization and Modeling .................... 121
5.4.1 General Aspects ................................... 122
5.4.2 Personal Area Network Scenarios ................... 124
5.4.3 Body Area Network Scenarios ....................... 129
5.4.4 Concluding Remarks ................................ 144
References .................................................... 147
CHAPTER 6
Wearable Antennas: Advances in Design, Characterization, and
Application ................................................... 151
6.1 Background ............................................... 151
6.2 Wearable Antennas: Critical Design Issues ................ 153
6.3 Textile Materials ........................................ 155
6.4 Effects of Substrate Materials: An Example of the
Fabric GPS Antenna ....................................... 156
6.4.1 Effects of Ground Plane Size Attached to the
Fabric Substrate on GPS Antenna Performance ....... 159
6.5 Effect of Various Conductive Materials of Patch
Antennas: An Example of WLAN Antenna on Fleece Fabric .... 162
6.6 Dual Frequency Wearable Antenna Design: An Example of a
U-Slot Patch ............................................. 166
6.6.1 Experimental Results and Discussions: Fleece and
Vellux Fabrics .................................... 169
6.7 Wearable Electromagnetic Bandgap Antenna: An Example of
WLAN Antenna ............................................. 171
6.7.1 Remarks on Antenna Bending ........................ 176
6.8 Wearable Antennas Near the Human Body: An Example of a
WLAN Antenna ............................................. 180
6.8.1 Models and Methods ................................ 180
6.8.2 Results ........................................... 181
6.9 Conclusions .............................................. 184
Acknowledgments ............................................... 186
References .................................................... 186
CHAPTER 7
Body-Sensor Networks for Space and Military Applications ...... 189
7.1 Introduction ............................................. 189
7.2 Biosensor System and Basics of Biomedical RF Telemetry ... 190
7.2.1 Implantable Pressure Sensor ....................... 192
7.2.2 Integrated Inductor/Antenna ....................... 192
7.2.3 External Pickup Antenna ........................... 194
7.3 Antenna Design for Body Sensors .......................... 194
7.3.1 Implantable Antennas .............................. 194
7.3.2 Antennas for External Handheld Devices ............ 203
7.4 Space, Military, and Civilian Applications ............... 206
7.4.1 Sensors for Space Environment ..................... 206
7.4.2 Battlefield Sensors ............................... 207
7.4.3 Sensors in Hospitals and Smart Homes .............. 207
References .................................................... 208
CHAPTER 8
Antennas and Propagation for Telemedicine and Telecare:
On-Body Systems ............................................... 211
8.1 Telemedicine and Telecare Applications .................. 211
8.1.1 Physiological Signals for Patient Monitoring ...... 213
8.1.2 Technologies for Ward-Based Systems ............... 213
8.1.1 Technologies for Home-Based and Full-Mobility
Systems ........................................... 215
8.1.4 Emerging Technologies and Novel Applications ...... 215
8.1.5 Wireless Telemedicine Link Design ................. 216
8.2 Antennas and Human Body Interaction in Personal
Telemedicine ............................................. 217
8.2.1 Antenna-Body Effects (Less Than 1 GHz) ............ 220
8.2.2 Antenna-Body Effects (Greater Than 1 GHz) ......... 224
8.2.3 Emerging Antennas ................................. 229
8.3 System Design Issues ..................................... 231
8.3.1 Channel Effects ................................... 231
8.3.2 Radio Frequency Interference ...................... 232
8.4 Conclusion ............................................... 236
References .................................................... 236
CHAPTER 9
Medical Implant Communication Systems ......................... 241
9.1 Introduction ............................................. 241
9.1.1 Inductive Coupling ................................ 242
9.1.2 MICS Standard ..................................... 243
9.1.3 2.4-GHz ISM Band .................................. 244
9.2 Lossy Dispersive Media ................................... 244
9.2.1 Matter ............................................ 244
9.2.2 Material Data and Measurements .................... 245
9.2.3 Phantoms .......................................... 246
9.2.4 Skin Depth ........................................ 249
9.2.5 Wave Propagation: One-Dimensional FDTD
Simulations ....................................... 250
9.2.6 Influence of Patient .............................. 253
9.2.7 Phantom Influence on Antenna ...................... 253
9.3 Low-Profile Antennas for Implantable Medical Devices ..... 255
9.3.1 What Is the Antenna? .............................. 256
9.3.2 Antenna Efficiency Calculations in Matter ......... 256
9.3.3 Electric Versus Magnetic Antennas ................. 258
9.3.4 Implantable Antenna Designs ....................... 260
9.3.5 Dependence on Insulation Thickness ................ 266
9.3.6 SAR ............................................... 267
9.4 Conclusion ............................................... 268
References .................................................... 269
CHAPTER 10
Summary and Conclusions ....................................... 271
10.1 Overview and Conclusions ................................. 271
10.1.1 Overview of Narrowband Systems .................... 271
10.1.2 Overview of Wideband Systems ...................... 274
10.1.3 Overview of Applications .......................... 274
10.1.4 Conclusions ....................................... 275
10.2 Future Challenges ........................................ 275
10.2.1 Towards Air Interfaces and New Standards .......... 275
10.2.2 Novel Antennas for Body-Centric Wireless
Communications .................................... 276
10.2.3 Medical Implant Systems ........................... 276
10.2.4 Characterization of Time-Domain Systems ........... 277
References .................................................... 277
About the Authors ............................................. 279
Index ......................................................... 289
|
