Microwave RF Applicators and Probes for Material Heating, Sensing, and Plasma Generation: A Design Guide

Copyright......Page 2
Dedication......Page 3
Preface......Page 4
Acknowledgements......Page 6
Introduction......Page 7
The wave equations and materials......Page 8
High-frequency electric fields and materials......Page 10
Energy deposition into materials with the dielectric loss effect......Page 12
Example......Page 13
High-frequency magnetic fields and materials......Page 14
Fields at boundaries between two real materials......Page 15
Wave impedance in various environments......Page 16
Lumped field approximations in electrically small systems......Page 18
Fields at conductor boundaries, skin depth, and surface resistance......Page 19
Standing waves in cavity and transmission-line applicators......Page 20
Penetration and reflection of waves into lossy dielectrics......Page 21
Distinction between dielectric loss and conductivity......Page 23
Temperature rise and thermal issues in electromagnetic heating......Page 24
Temperature rise and energy losses......Page 25
Special and non-thermal electromagnetic effects on materials......Page 26
Nonlinearity issues and thermal runaway in electromagnetic heating......Page 27
Ceramics and glasses......Page 28
Polymers and plastics......Page 29
Conductive materials: metals and carbon-based conductors......Page 30
Water and water-rich organic materials......Page 31
High-frequency properties of biological and live tissues......Page 34
Gases/vapors......Page 35
Metamaterials/periodic structures......Page 36
References......Page 37
Introduction......Page 41
Far field and near field: antennas versus applicators/probes......Page 42
Electrically small and electrically large applicators......Page 43
Applicator/probe categorization based on applicator/material load geometry......Page 44
Applicator coupling, efficiency, and power management......Page 45
Fill factor of applicators and probes......Page 47
Field uniformity: definition and contributing factors......Page 49
Electric field applicator/probes......Page 50
Magnetic field (inductive coil) applicators/probes......Page 52
Lumped resonance: fields and energy storage......Page 53
Distributed resonance: field and energy storage......Page 55
Resonant frequency......Page 56
Quality factor, bandwidth, and efficiency in resonant applicators......Page 58
Parasitic energy storage in resonant applicators and probes......Page 60
Improving applicator efficiency and probe sensitivity......Page 61
Self-resonant and semi-lumped applicator/probes......Page 63
Cavity resonators as applicators or probes......Page 64
Non-resonant and transmission-line applicators and probes......Page 65
Material loading effects......Page 67
Reciprocity between applicators and probes: sensitivity......Page 68
Applicators/probes for ISM applications across the frequency spectrum......Page 69
References......Page 71
Introduction......Page 73
Description and definitions......Page 74
Field configurations and methods of analysis......Page 75
Field uniformity and methods of improvement......Page 77
E-field applicators for material heating and plasma activation: principles......Page 79
E-field probes as dielectic material sensors......Page 80
Asymmetrical E-field electrode systems for localized heating: medical RF ablation......Page 82
Parallel-plate E-field applicator with stratified dielectric layers: equivalent circuit and field calculations......Page 84
Equivalent circuit and fields for parallel-plate applicators with two lossy dielectric layers......Page 85
Equivalent circuit of parallel plates partially filled with lossy dielectric......Page 86
Quality factor of partially filled parallel plates with lossy dielectric......Page 88
Parallel-plate applicator partially filled with a conductive material......Page 89
Approximate equivalent circuit of a lossy dielectric pill in parallel plates......Page 90
Resonance and efficiency in E-field applicators......Page 91
Coupling to external circuits for E-field applicators......Page 94
Fringing-field, interdigital, and stray-field applicators and probes......Page 96
Common characteristics and applications of fringing-field and interdigital electrode systems......Page 97
Analysis methods and computation of electrode capacitance......Page 98
Alternate configurations and applications of interdigital dielectric sensors......Page 100
Stray-field and through-field applicators for RF heating of planar materials......Page 102
Advantages and characteristics of RF heating......Page 103
Electric field strength inside and outside of material in RF heating......Page 104
Currents and voltages in RF heating systems......Page 106
Modern RF heating system configurations......Page 109
Wavelength effects and standing waves in RF heating electrodes......Page 111
References......Page 112
Introduction......Page 115
Configurations of field–material interactions: basics of single-mode cavities......Page 116
Description of material loading effects in single mode cavities......Page 117
Comparison of single-mode cavities with other applicator/probe types......Page 118
Applications of single-mode cavities for material processing and sensing......Page 119
Dielectric measurements......Page 120
Methods for determination of field distribution, material effects, coupling, and electrical parameters of single-mode cavities......Page 121
Field configuration and geometry of TM010 cavity......Page 123
The resonant frequency, quality factor, and tuning issues......Page 124
Coupling methods and interface with external circuits......Page 127
Dual-port cavities, insertion loss, and return loss......Page 130
Equivalent circuit of a cylindrical TM010 cavity......Page 131
Material loading impact in single-mode cavities: approximate and rigorous methods......Page 133
The perturbation method for material loading studies......Page 134
Application example: use of perturbation method in the design of a sensor with a cylindrical TM010 mode cavity......Page 135
Example......Page 136
Solution......Page 137
Application example: industrial application of TM020 cavities for viscous liquid heating......Page 138
TE10n waveguide-based single-mode cavities......Page 139
Application example: rectangular TE101 cavity for gas-phase catalysis......Page 143
Cylindrical TE011 and other cavities for interactions with sheet dielectrics......Page 145
Some special and alternative applications of single-mode cavities......Page 146
The use of solid-state amplifiers for feeding of single-mode heating cavities......Page 149
Magnetron injection locking for single-mode cavities used in material heating......Page 151
The general process for the design of single-mode cavities for material interactions......Page 152
References......Page 153
Introduction......Page 157
Description of fields and resonant modes in multimode cavities......Page 158
Resonant frequency and number of possible modes in multimode cavities......Page 160
The optical beam method of studying multimode cavity behavior......Page 162
A phenomenological description of power source/multimode cavity interactions......Page 164
Comparison of multimode cavities with other RF/microwave applicators......Page 166
Methods for computation of energy distribution......Page 167
Factors other than fields that contribute to non-uniform heating......Page 170
Mechanical movement methods to improve heating uniformity......Page 171
Frequency sweeping/multi-frequency methods to improve field uniformity......Page 173
Coupling structures for optimum transfer and uniformity......Page 174
Multiple port/multiple source coupling for improvement of uniformity and increase of total microwave power......Page 176
Principles of microwave susceptors......Page 177
Planar susceptors for food applications......Page 178
Metallic field modification devices in multimode ovens......Page 179
Modified domestic microwave ovens for continuous power adjustment and control......Page 181
Multimode applicators for plasma generation......Page 182
Microwave fluidized bed applicators......Page 183
References......Page 185
Introduction......Page 189
Basic structure and equivalent circuit......Page 190
Field of view (field of coverage)......Page 191
Categories of open-ended applicator/probes......Page 192
Open-ended parallel strips......Page 193
Effective field interaction volume......Page 194
Impedance mismatch and signal/power transfer to the material......Page 195
Equivalent circuit of open-ended transmission-line applicators......Page 197
Open-ended coaxial transmission-line probes......Page 198
Analytical solutions for the admittance of the open-ended coaxial probe......Page 199
Advantages and limitations of material characterization with open-ended coaxial probes......Page 201
Factors in performance optimization of open-ended coaxial lines......Page 202
Extended coaxial-line (monopole antenna) applicators......Page 204
Application example: microwave drill......Page 208
Industrial material measurements using resonant coaxial probe......Page 209
Application example: microwave microscopy with focused open-ended coaxial transmission lines......Page 211
Open-ended waveguide, horn, and cavity applicators......Page 212
Open-ended waveguides as near-field applicators and probes......Page 213
Horn applicators......Page 214
Array and lens applicators......Page 217
Over-moded dielectric-filled open cavity applicators......Page 218
References......Page 221
Introduction......Page 225
H-field probes: categorization of applications and applicator/probe types at high frequencies......Page 226
The eddy current effect and its formation......Page 227
High-frequency magnetic fields imposed on ferromagnetic materials......Page 230
Magnetic resonance applications of H-field applicators......Page 232
Frequencies and power levels for various applications of H-field applicators/probes......Page 233
Field patterns in inductive applicators......Page 234
Inductive applicator definitions and circuit parameters......Page 237
A simplified model of a conductive load in a uniform AC magnetic field......Page 238
Wire/filament magnetic/inductive applicators (coils)......Page 240
Current foil-type magnetic applicators......Page 241
Resonant cavity-type magnetic field applicators......Page 242
Saddle coils and H-field applicators designed for specific field direction......Page 244
Description and field distribution of solenoid-type applicators......Page 245
Inductance......Page 246
Spiral-type applicators......Page 247
High-frequency issues, stray electric field, and self-resonance......Page 248
Induction heating of a hollow cylindrical shell......Page 251
Solution......Page 253
Energy deposition into a cylindrical load from a uniform magnetic field......Page 254
Induction heating of a cylindrical load in a solenoid-type coil......Page 255
Practical issues in high-frequency induction heating......Page 257
Uniformity of energy deposition in induction heating......Page 258
Application example: induction heating leading to silicon–silicon wafer bonding......Page 259
Applicator current, voltage, and power efficiency......Page 260
Resonance and the tank capacitor......Page 262
Coupling circuits for H-field applicators and coils......Page 263
Answer......Page 265
Applications of induction heating of packed beds......Page 266
Example......Page 269
References......Page 270
Introduction......Page 275
Electromagnetic fusion welding......Page 276
Electromagnetic joining with curable adhesives or joining agents......Page 277
Electromagnetic joining with susceptive implants......Page 279
RF Fusion welding of thermoplastics: applicator and system considerations......Page 280
System and process for RF fusion welding......Page 281
Parallel-plate welding applicator: RF power requirements considering heat losses......Page 283
Solution......Page 284
Parallel-plate welding applicator fields, power, and voltage for fusion welding......Page 285
Failure mechanisms in RF welding......Page 286
Dielectric buffer layer in RF fusion welding......Page 287
Electrode edge overheating/arcing and the use of a conjugate (symmetrical) electrode to reduce it......Page 289
Parameters and tradeoffs, and limitations in RF fusion welding......Page 290
System/circuit schemes in RF welding......Page 292
Arc detection circuit for the applicator in RF welding......Page 293
Applicator configurations in microwave welding......Page 294
Joining agents or implant materials for microwave welding......Page 297
Magnetic field/inductive applicators for joining of materials......Page 298
Applicator types used for inductive welding......Page 299
system issues in induction welding......Page 300
References......Page 302
Introduction......Page 306
Power requirements for a continuous system......Page 307
Relationship between the product flow rate and process geometry......Page 308
Heating uniformity issues in RF/microwave conveyor systems......Page 309
Temperature and control issues in continuous systems......Page 310
General theory of continuous RF/microwave processing......Page 311
Preparation for continuous process design and collection of basic data......Page 312
RF parallel-plate continuous system......Page 313
Continuous process example: RF drying of temperature-sensitive herbicide granules......Page 314
Continuous process example: RF processing of polyamide pellets with thermal runaway......Page 317
Resonant single-mode continuous processing of webs and multi-strand fibers......Page 322
Meandering (serpentine) microwave waveguide applicators......Page 324
Longitudinal-flow waveguide applicators (standing-wave applicators)......Page 329
Introduction......Page 330
Cutoff frequencies for cylindrical and rectangular waveguides......Page 333
Below-cutoff attenuation ducts (chokes)......Page 334
Above-cutoff attenuation ducts for product entry/exit (vestibules)......Page 335
Resonant (reflective) choking methods of attenuation tunnels......Page 336
References......Page 337
Mode Chart for Cylindrical Cavities......Page 340
Impedance/Admittance and Electric Field Solutions for a Parallel-plate Applicator with Dual Layers of Real Dielectric Materials......Page 341
Mathematica™ Worksheet for Derivation of Dual-layer Parallel Plates with Real Dielectrics......Page 344
Field Analysis of TM0n0 Cylindrical Cavities with Two Concentric Layers of Real Dielectric at the Axis......Page 346
Mathematica™ Notebook for Computation of Single-mode TM0n0 Cavities for Material Heating and Sensing Applications......Page 349
Analysis of an Example of Rectangular Cavity Mode for Power Density......Page 353
Mathematica™ Notebook for Computation of Possible Modes Over a Given Bandwidth for a Rectangular Multimode Cavity......Page 356
Mathematica™ Worksheet for Finding the Admittance and Equivalent Circuit Parameters of the Open-ended Coaxial Probe......Page 358
Mathematica™ Notebook for Impedance of the Extended Center Conductor Coaxial Line......Page 360
Admittance of Open-ended Waveguide with Dielectric Material Loading......Page 362
Field Analysis of Circular Loop Applicator......Page 364
Mathematica™ Program for Eddy Current Induction into a Conductive Cylinder......Page 367
Selected Information on Frequency Allocations for ISM (Industrial, Scientific, and Medical) Applications......Page 379
RF/Microwave Safety......Page 381
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R......Page 391
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W......Page 394