ISBN: 3-540-67232-X
TITLE: Surface Acoustic Wave Devices in Telecommunications
AUTHOR: Hashimoto, Ken-ya
TOC:

1. Bulk Acoustic and Surface Acoustic Waves 1
1.1 Bulk Acoustic Waves1
1.1.1 Elastic Waves in Solids 1
1.1.2 Wavevector and Group Velocity 4
1.1.3 Behavior of BAWs at a Boundary 6
1.1.4 Diffraction. 8
1.1.5 Piezoelectricity 8
1.1.6 Evanescent Fields 11
1.1.7 Waveguides 12
1.1.8 Behavior at the Boundary Between Waveguides 13
1.1.9 Open Waveguides 15
1.2 Waves in a Semi-infinite Substrate 17
1.2.1 Excitation of L- and SV-type Waves 17
1.2.2 Excitation of SH-type Waves 18
1.2.3 Leaky SAWs 20
1.2.4 Leaky and Nonleaky SAWs 21
1.2.5 SSBW 22
References 22
2. Grating 25
2.1 Basic Structure 25
2.1.1 Fundamentals 25
2.1.2 Reflection Center 26
2.2 Behavior in Periodic Structures 27
2.2.1 Bragg Reflection 27
2.2.2 Energy Storing Effect 30
2.2.3 FabryPerot Resonator 31
2.3 Equivalent Circuit Analysis 32
2.3.1 Analysis 32
2.3.2 Dependence of Reflection Characteristics on Parameters 35
2.4 Metallic Grating 39
2.4.1 Fundamental Characteristics 39
2.4.2 SAW Dispersion Characteristics 40
2.4.3 Approximated Dispersion Characteristics 42
References 46
3. Interdigital Transducers 47
3.1 Fundamentals 47
3.1.1 Bidirectional IDTs 47
3.1.2 Unidirectional IDTs 48
3.2 Static Characteristics 52
3.2.1 Charge Distribution 52
3.2.2 Electromechanical Coupling Factor 53
3.2.3 Element Factor 55
3.2.4 Complex Electrode Geometries 56
3.2.5 Effect of IDT Ends 59
3.3 IDT Modeling 61
3.3.1 Delta-Function Model 61
3.3.2 Equivalent Circuit Model 65
3.3.3 Other Models 66
3.4 Influence of Peripheral Circuit 68
3.4.1 Summary 68
3.4.2 Smith Chart and Impedance Matching 70
3.4.3 Achievable Bandwidth 73
3.5 p Matrix 74
3.5.1 Summary 74
3.5.2 IDT Characterization by Using p Matrix 76
3.5.3 Discussion on Unidirectional IDTs 77
3.6 BAW Radiation 79
3.6.1 Phase Matching Condition 79
3.6.2 Radiation Characteristics 81
References 84
4. Transversal Filters 87
4.1 Basics 87
4.1.1 Weighting 87
4.1.2 Basic Properties of Weighted IDTs 91
4.1.3 Effects of Peripheral Circuits 92
4.2 Design of Transversal Filters 97
4.2.1 Fourier Transforms 97
4.2.2 Remez Exchange Method 100
4.2.3 Linear Programming 101
4.3 Spurious Responses 103
4.3.1 Diffraction. 103
4.3.2 Bulk Waves 107
4.3.3 Other Parasitic Effects 110
4.4 Low-Loss Transversal Filters 112
4.4.1 Multi-IDT Structures 112
4.4.2 Transversal Filters Employing SPUDTs 114
4.4.3 Combination of SPUDTs and Reflectors 117
References 120
5. Resonators 123
5.1 One-Port SAW Resonators 123
5.1.1 Introduction 123
5.1.2 FabryPerot Model 127
5.2 Spurious Responses 130
5.2.1 Beam Diffraction and Transverse Modes 130
5.2.2 Transverse-Mode Analysis 131
5.2.3 Effect of BAW Radiation 138
5.3 Two-Port SAW Resonators 141
5.3.1 Summary 141
5.3.2 FabryPerot model 143
5.3.3 Multi-Mode Resonator Filter 145
5.3.4 Cascade Connection of Resonators 148
5.4 Impedance Element Filters 149
5.4.1 pi-Type Filters 149
5.4.2 Lattice-Type Filters 152
5.4.3 Ladder-Type Filters 153
References 160
6. Selection of Substrate Material 163
6.1 Substrate Material and Device Characteristics 163
6.1.1 Orientation 163
6.1.2 Influence of Substrate and Electrode Materials 164
6.2 Evaluation of Acoustic Properties by Effective Permittivity 167
6.2.1 Effective Permittivity 167
6.2.2 Approximate Expressions 173
6.3 Single Crystals 174
6.3.1 Quartz 174
6.3.2 LiNbO_3 176
6.3.3 LiTaO_3 179
6.3.4 Li_2B_4O_7 182
6.3.5 Langasite 183
6.4 Thin Films 184
References 188
7. Coupling-of-Modes Theory 191
7.1 Fundamentals 191
7.1.1 Collinear Coupling 191
7.1.2 Periodic Structures 196
7.1.3 Excitation 200
7.2 COM Theory for SAW Devices 200
7.2.1 Derivation 200
7.2.2 COM Equations in Other Forms 203
7.2.3 Inclusion of Electrode Resistivity 204
7.2.4 Examples 206
7.3 Determination of COM Parameters 214
7.3.1 Perturbation Theory 214
7.3.2 Wave Theory Based Analysis 216
7.3.3 Analysis for Multi-Electrode IDTs 221
7.4 COM-Based Simulators 227
7.4.1 SAW Device Simulation 227
7.4.2 Inclusion of Peripheral Circuit 230
7.4.3 Results of Simulation 231
References 235
8. Simulation of SH-type SAW Devices 237
8.1 Physics of SH-Type SAWs 237
8.1.1 Summary 237
8.1.2 Propagation and Excitation on a Uniform Surface 237
8.1.3 Behavior on a Grating 243
8.1.4 Electrical Characteristics of IDTs 246
8.1.5 Effects of Back-Scattered BAWs 248
8.1.6 Influence of Grating Edge 249
8.2 COM Theory for SH-Type SAWs 250
8.2.1 COM Parameter Derivation 250
8.2.2 Simulation 254
8.2.3 COM Parameters for Rayleigh-Type SAWs 263
8.3 Derivation of Approximate Dispersion Relations 266
8.3.1 Derivation of Plessky's Dispersion Relation 266
8.3.2 Derivation of Abbott's Dispersion Relation 267
References 268
A. Physics of Acoustic Waves 271
A.1 Elasticity of Solids 271
A.2 Piezoelectricity 275
A.3 Surface Acoustic Waves 278
A.4 Effective Acoustic Admittance Matrix and Permittivity 282
A.5 Acoustic Wave Properties in 6mm Materials 284
A.5.1 Rayleigh-Type SAWs 284
A.5.2 Effective Permittivity for BGS Waves 285
A.5.3 Effective Acoustic Admittance Matrix 287
A.6 Wave Excitation 287
A.6.1 Integration Path 287
A.6.2 Electrostatic Coupling 288
A.6.3 BGS Wave Excitation 289
A.6.4 SSBW Excitation 290
References 291
B. Analysis of Wave Propagation on Grating Structures 293
B.1 Summary 293
B.2 Metallic Gratings 294
B.2.1 Bltekjr's Theory for Single-Electrode Gratings 294
B.2.2 Wagner's Theory for Oblique Propagation 296
B.2.3 Aoki's Theory for Double-Electrode Gratings 297
B.2.4 Extension to Triple-Electrode Gratings 301
B.3 Analysis of Metallic Gratings with Finite Thickness 304
B.3.1 Combination with Finite Element Method 304
B.3.2 Application to Extended Bltekjr Theories 306
B.4 Wave Excitation and Propagation in Grating Structures 310
B.4.1 Effective Permittivity for Grating Structures 310
B.4.2 Evaluation of Discrete Green Function 312
B.4.3 Delta-Function Model 315
B.4.4 Infinite IDTs 316
References 318
Index 321
END
