About the Authors xiii -- Preface xiv -- Acknowledgments xvi -- List of Abbreviations xviii -- About the Companion Website xx -- Part I Principles 1 -- 1 Background 3 -- 1.1 Introduction 3 -- 1.1.1 Filters Necessity 3 -- 1.1.2 Alternative Filtering Methods 4 -- 1.2 Filter Anatomy and Representation 5 -- 1.2.1 The Basic Coupling Matrix (M Matrix) 5 -- 1.2.2 Coupling-Routing Diagrams 8 -- 1.2.3 Additions to the Coupling Matrix for Synthesis of Advanced and Practical Filter Responses 10 -- 1.2.3.1 Positive and Negative Coupling Values 10 -- 1.2.3.2 Finite Resonator Quality Factors 11 -- 1.2.3.3 Resonator Frequency Tuning 13 -- 1.2.3.4 Non-Resonating Nodes 13 -- 1.2.3.5 Complex Impedance Loads 16 -- 1.3 Tunable Resonators in Filters 20 -- 1.3.1 Planar Tunable Resonators 21 -- 1.3.2 Ferrimagnetic Tunable Resonators 22 -- 1.3.3 Evanescent-Mode 3-D Tunable Resonators 22 -- 2 Evanescent-Mode Resonators 25 -- 2.1 Physical Structure 25 -- 2.2 Analysis 26 -- 2.2.1 Coaxial Cable Approximation 26 -- 2.2.1.1 Unloaded Quality Factor 28 -- 2.2.2 Tapered Resonator Model 30 -- 2.2.2.1 Frequency Tuning Ratio 34 -- 2.2.3 Tuning Range and Quality Factor Co-optimization 37 -- 2.3 Coupling Techniques 38 -- 2.3.1 External Coupling 38 -- 2.3.2 Inter-Resonator Coupling 43 -- 2.4 Coupling Values Polarity 44 -- 2.4.1 External Coupling Polarity 44 -- 2.4.2 Inter-Resonator Coupling Polarity 45 -- 2.5 Advanced Evanescent-Mode Structures 48 -- 2.5.1 Dual-Mode Resonators 48 -- 2.5.2 Fractional Mode Resonators 49 -- 2.6 Filter Examples 51 -- 2.6.1 Chebyshev Bandpass Filter 51 -- 2.6.2 Butterworth Bandstop Filter 53 -- Part II Implementation 55 -- 3 Printed Circuit Board Technology 57 -- 3.1 Evanescent-Mode Resonator Structure 57 -- 3.1.1 Practical Considerations 58 -- 3.2 Tunable Membrane 60 -- 3.2.1 Piezoelectric Disk Tuners 60 -- 3.2.2 Contactless Mechanical Actuators 61 -- 4 Silicon Microfabrication 65 -- 4.1 Generic Structure 65 -- 4.2 MEMS Tuner Design 66 -- 4.3 Microfabrication Process 68 -- 4.3.1 MEMS Tuner Microfabrication 68 -- 4.3.2 Evanescent-Mode Resonator Microfabrication 69 -- 4.3.3 Bias Electrode Microfabrication 69 -- 4.3.4 Filter Assembly 70 -- 4.4 Mechanical Model and Power Handling 72 -- 5 Injection Molding 77 -- 5.1 Manufacturing Technology 77 -- 5.1.1 Device Concept 77 -- 5.1.2 Injection Molding Technology 78 -- 5.1.3 Material Selection 80 -- 5.1.4 Design for Moldability 81 -- 5.2 Resonator and Filter RF Design 82 -- 5.2.1 Resonator 82 -- 5.2.2 Filter 83 -- 5.3 Fabrication and Measurements 85 -- 5.3.1 Resonator 85 -- 5.3.2 Filter Performance Measurements 87 -- 5.3.3 Power Handling 90 -- 5.4 Discussion 93 -- 5.5 Conclusion 95 -- 5.6 How to Choose the Right Manufacturing Technology 95 -- 5.7 How to Choose the Right Actuator for the Filter 96 -- Part III Applications 99 -- 6 Absorptive Bandstop Filters 101 -- 6.1 Design Principles of Absorptive Filters 101 -- 6.1.1 Analysis of a Two-Pole Absorptive Bandstop Filter 101 -- 6.1.2 W-Band Absorptive Bandstop Filter 104 -- 6.1.2.1 Filter Design 104 -- 6.1.2.2 Fabrication and Measurements 107 -- 6.2 Triplet Quasi-absorptive Topology 109 -- 6.2.1 Quasi-absorptive Filter Design and Implementation 111 -- 6.2.1.1 Measured Results 114 -- 7 Bandwidth and Passband Control 115 -- 7.1 Bandwidth Control for Bandpass Filters 115 -- 7.1.1 Filter Design 116 -- 7.1.1.1 Bandwidth Variation 116 -- 7.1.1.2 Quality Factor Impact 118 -- 7.1.1.3 Impedance Matching 119 -- 7.1.1.4 Simulated Results 120 -- 7.1.2 Filter Implementation 122 -- 7.2 BSF Bandwidth Control 126 -- 7.2.1 Constant Bandwidth Coupling Concept 128 -- 7.2.1.1 BWVariation Versus T-Line Length and Tuning Range 131 -- 7.2.1.2 Phase Variation 134 -- 7.2.2 Constant Bandwidth Filter Design 136 -- 7.2.2.1 External Coupling 136 -- 7.2.2.2 External Coupling Structures: Polarity Design 138 -- 7.2.2.3 Inter-Resonator Coupling 140 -- 7.2.3 Fabrication and Measurements 141 -- 7.2.3.1 Constant FBW Filter 142 -- 7.2.3.2 Constant ABW Filter 143 -- 7.2.3.3 Four-Pole Filter 144 -- 8 High-Order and Fractional-Order Evanescent-Mode Filters 147 -- 8.1 High-Order Evanescent-Mode Filters 147 -- 8.1.1 Independently Tunable Dual-Mode Evanescent-Mode Filter 147 -- 8.1.1.1 Resonator Design 148 -- 8.1.1.2 Filter Design 150 -- 8.1.1.3 Experimental Validation 151 -- 8.1.2 High Selectivity Dual-Mode Filters 152 -- 8.1.2.1 Resonator Design 154 -- 8.1.2.2 Constant Absolute Bandwidth BPF Filter 157 -- 8.1.2.3 Filter A: Implementation and Validation 160 -- 8.1.2.4 Filter B: Implementation and Validation 161 -- 8.1.2.5 Filter C: Implementation and Validation 162 -- 8.1.2.6 Filter D: Implementation and Validation 162 -- 8.1.3 Four-Wedge Evanescent-Mode Resonator 165 -- 8.1.3.1 Bandpass Filter Design 165 -- 8.1.3.2 Design Example 167 -- 8.2 Tunable Half-Mode SIW Filter 170 -- 9 Advanced Evanescent-Mode Filter Structures 175 -- 9.1 Bandpass-to-bandstop Reconfigurable Filter 175 -- 9.1.1 Bandpass-to-bandstop Filter Theory 176 -- 9.1.1.1 Coupling Structure to Switch M01 and M03 Simultaneously 177 -- 9.1.2 Bandpass-to-bandstop Reconfigurable Filter Design 179 -- 9.1.3 Measured Results 180 -- 9.2 Field-programmable Filter Array 184 -- 9.2.1 Positive-to-negative Coupling Structure 184 -- 9.2.2 Response Enhancements Enabled By Positive-to-negative Inter-Resonator Coupling 185 -- 9.2.2.1 Zero Net Coupling State Enhancement Using Destructive Interference 185 -- 9.2.2.2 Local Stopband Attenuation Enhancement Technique 187 -- 9.2.3 Resonator Array Design and Fabrication 188 -- 9.2.4 Measured Results 189 -- 10 Passive Applications 195 -- 10.1 Impedance Tuner 195 -- 10.1.1 Design and Fabrication 195 -- 10.1.2 Measured Results 197 -- 10.2 Single-ended (SE) and Balanced (BAL) Diplexers 198 -- 10.2.1 Dual-Mode Diplexing Concept 198 -- 10.2.1.1 Diplexing Architecture 198 -- 10.2.1.2 Resonant Frequency Misalignment 199 -- 10.2.1.3 Inter-Resonator Coupling 201 -- 10.2.2 SE–SE Diplexer Implementation and Measurements 201 -- 10.2.2.1 External Coupling 201 -- 10.2.2.2 Measured Results 201 -- 10.2.3 SE–BAL Diplexer Implementation and Measurements 202 -- 10.2.3.1 External Coupling 202 -- 10.2.3.2 Measured Results 203 -- 10.2.4 BAL–BAL Diplexer Implementation and Measurements 205 -- 10.2.4.1 External Coupling 205 -- 10.2.4.2 Measured Results 205 -- 10.3 Tunable Filtering Rat-race Couplers Based on Half- and Full-mode Evanescent-mode Resonators 207 -- 10.3.1 Design 207 -- 10.3.2 Full-mode Rat-race Coupler 209 -- 10.3.2.1 Experimental Validation 209 -- 10.3.3 Half-mode Rat-race Coupler 210 -- 10.3.3.1 Half-mode Structure 210 -- 10.3.3.2 Experimental Validation 211 -- 11 Active Applications 215 -- 11.1 Co-Design of Power Amplifiers and High-Q Filters 215 -- 11.1.1 Filter Design 216 -- 11.1.2 Transistor Characterization 217 -- 11.1.3 Matching Filter Design 217 -- 11.1.3.1 Fundamental and Harmonic Matchings 219 -- 11.1.4 PA Design 220 -- 11.1.5 Experimental Results 220 -- 11.1.6 Co-Design of PA and Three-Pole High-Q Tunable Filter 222 -- 11.2 Phase-Locked Loop 224 -- 11.2.1 Frequency Synthesizer Architecture and Phase Noise Model 224 -- 11.2.2 Circuit Design and Optimizations 226 -- 11.2.2.1 Evanescent-Mode Cavity Resonator 226 -- 11.2.2.2 Voltage-Controlled Oscillator Design 226 -- 11.2.2.3 Phase-Locked Loop Design 227 -- 11.2.2.4 Measured Results 229 -- 11.3 Balanced–Balanced Tunable Filtering LNA 231 -- 11.3.1 Cavity Resonator-LNA Co-Design 231 -- 11.3.1.1 Evanescent-Mode Resonators 232 -- 11.3.1.2 LNA 232 -- 11.3.2 Implementation and Measured Results 233 -- 12 Monitoring and Control 235 -- 12.1 Monitoring and Control of PCB-based Resonators: Diplexer Example 235 -- 12.1.1 System Architecture 235 -- 12.1.1.1 Diplexer 236 -- 12.1.1.2 Resonators Monitoring and Control 237 -- 12.1.1.3 Spectrum Sensing 240 -- 12.1.2 Control Loop Analysis 242 -- 12.1.3 Design Details 242 -- 12.1.3.1 Diplexer Structure 242 -- 12.1.3.2 Oscillator and Frequency Counter 243 -- 12.1.3.3 Control Unit and Charge Pump 246 -- 12.1.4 Implementation and Measurements 247 -- 12.1.4.1 Implementation 247 -- 12.1.4.2 Monitoring Performance 248 -- 12.1.4.3 RF Performance 250 -- 12.1.4.4 Spectrum-aware Measurements 254 -- 12.2 Monitoring and Control of Silicon-based Filters 254 -- 12.2.1 Monitoring Concepts and Optimizations 255 -- 12.2.1.1 Inductive Proximity Sensing 255 -- 12.2.1.2 Circuit Optimization 257 -- 12.2.1.3 Spiral Inductor 261 -- 12.2.2 Control System Design 261 -- 12.2.3 Testbed Filter Design 263 -- 12.2.4

Implementation and Measurements 263 -- 12.2.4.1 Fabrication 263 -- 12.2.4.2 Sensing Feedback 265 -- 12.2.4.3 Filter Monitoring and Control 266 -- 12.3 Monitoring and Control Applications: Temperature Compensation 267 -- 12.3.1 Temperature Control 268 -- 12.3.1.1 Temperature Compensation System Implementation 268 -- 12.3.1.2 Room Temperature Filter Performance 268 -- 12.3.1.3 Temperature Compensation Performance 268 -- References 275 -- Index 289.