Advanced Design Techniques and Realizations of Microwave and RF Filters

The fundamentals needed to design and realize microwave and RF filters. Microwave and RF filters play an important role in communication systems and, owing to the proliferation of radar, satellite, and mobile wireless systems, there is a need for design methods that can satisfy the ever-increasing demand for accuracy, reliability, and shorter development times. Beginning with a brief review of scattering and chain matrices, filter approximations and synthesis, waveguides and transmission lines, and fundamental electromagnetic equations, the book then covers design techniques for microwave and RF filters operating across a frequency range from 1 GHz to 35 GHz. Each design chapter: Is dedicated to only one filter and is organized by the type of filter response Provides several design examples, including the analysis and modeling of the structures discussed and the methodologies employed Offers practical information on the actual performance of the filters and common difficulties encountered during construction Concludes with the construction technique, pictures of the inside and outside of the filter, and the measured performances Advanced Design Techniques and Realizations of Microwave and RF Filters is an essential resource for wireless and telecommunication engineers, as well as for researchers interested in current microwave and RF filter design practices. It is also appropriate as a supplementary textbook for advanced undergraduate courses in filter design.

Table of Contents:
Foreword xiii Preface xv PART I MICROWAVE FILTER FUNDAMENTALS 1 1 Scattering Parameters and ABCD Matrices 3 1.1 Introduction 3 1.2 Scattering Matrix of a Two-Port System 4 1.2.1 Definitions 4 1.2.2 Computing the S Parameters 6 1.2.3 S-Parameter Properties 10 1.3 ABCD Matrix of a Two-Port System 10 1.3.1 ABCD Matrix of Basic Elements 11 1.3.2 Cascade and Multiplication Property 12 1.3.3 Input Impedence of a Loaded Two-Port 14 1.3.4 Impedance and Admittance Inverters 14 1.3.5 ABCD-Parameter Properties 17 1.4 Conversion from Formulation S to ABCD and ABCD to S 18 1.5 Bisection Theorem for Symmetrical Networks 18 1.6 Conclusions 21 References 21 2 Approximations and Synthesis 23 2.1 Introduction 23 2.2 Ideal Low-Pass Filtering Characteristics 24 2.3 Functions Approximating the Ideal Low-Pass Magnitude Response 25 2.3.1 Butterworth Function 25 2.3.2 Chebyshev Function 26 2.3.3 Elliptic Function 27 2.3.4 Generalized Chebyshev (Pseudoelliptic) Function 29 2.4 Functions Approximating the Ideal Low-Pass Phase Response 30 2.4.1 Bessel Function 30 2.4.2 Rhodes Equidistant Linear-Phase Function 31 2.5 Low-Pass Lumped Ladder Prototypes 32 2.5.1 General Synthesis Technique 32 2.5.2 Normalized Low-Pass Ladders 36 2.6 Impedance and Frequency Scaling 39 2.6.1 Impedance Scaling 39 2.6.2 Frequency Scaling 40 2.7 LC Filter Example 41 2.8 Impedance and Admittance Inverter Ladders 41 2.8.1 Low-Pass Prototypes 41 2.8.2 Scaling Flexibility 42 2.8.3 Bandpass Ladders 44 2.8.4 Filter Examples 45 2.9 Conclusions 46 References 46 3 Waveguides and Transmission Lines 49 3.1 Introduction 49 3.2 Rectangular Waveguides and Cavities 49 3.2.1 Rectangular Waveguides 49 3.2.2 Rectangular Cavities 52 3.3 Circular Waveguides and Cavities 53 3.3.1 Circular Waveguides 53 3.3.2 Cylindrical Cavities 55 3.4 Evanescent Modes 56 3.5 Planar Transmission Lines 57 3.6 Distributed Circuits 60 3.7 Conclusions 63 References 64 4 Categorization of Microwave Filters 67 4.1 Introduction 67 4.2 Minimum-Phase Microwave Filters 68 4.2.1 General Design Steps 68 4.2.2 Minimum-Phase Filter Examples 70 4.3 Non-Minimum-Phase Symmetrical Response Microwave Filters 70 4.3.1 General Design Steps 71 4.3.2 Non-Minimum-Phase Symmetrical Response Filter Examples 73 4.3.3 Microwave Linear-Phase Filters 73 4.4 Non-Minimum-Phase Asymmetrical Response Microwave Filters 74 4.4.1 General Design Steps 74 4.4.2 Non-Minimum-Phase Asymmetrical Response Filter Examples 77 4.4.3 Multimode Microwave Filters by Optimization 79 4.5 Conclusions 79 References 80 PART II MINIMUM-PHASE FILTERS 83 5 Capacitive-Gap Filters for Millimeter Waves 85 5.1 Introduction 85 5.2 Capacitive-Gap Filters 86 5.2.1 Capacitive-Gap Filter Structure 86 5.2.2 Design Procedures 87 5.2.3 Step-by-Step Design Example 91 5.2.4 Filter Realizations 93 5.3 Extension to Millimeter Waves 95 5.3.1 Millimeter-Wave Technology 95 5.3.2 Fifth-Order Chebyshev Capacitive-Gap Filter at 35 GHz 96 5.4 Electromagnetic Characterization of SSS 99 5.5 Conclusions 102 References 102 6 Evanescent-Mode Waveguide Filters with Dielectric Inserts 105 6.1 Introduction 105 6.2 Evanescent-Mode Waveguide Filters 106 6.2.1 Scattering and ABCD Descriptions of the Structure 108 6.2.2 Equivalent Circuit of the Structure 110 6.2.3 Filter Design Procedure 115 6.2.4 Design Examples and Realizations 117 6.3 Folded Evanescent-Mode Waveguide Filters 121 6.3.1 Scattering and ABCD Descriptions of the Additional Elements 123 6.3.2 Filter Design Procedure 125 6.3.3 Design Examples and Realizations 125 6.4 Conclusions 127 References 128 7 Interdigital Filters 131 7.1 Introduction 131 7.2 Interdigital Filters 131 7.3 Design Method 135 7.3.1 Prototype Circuit 135 7.3.2 Equivalent Circuit 137 7.3.3 Input and Output 140 7.3.4 Case of Narrowband Filters 141 7.3.5 Frequency Transformation 141 7.3.6 Physical Parameters of the Interdigital Filter 142 7.4 Design Examples 145 7.4.1 Wideband Example 145 7.4.2 Narrowband Example 147 7.5 Realizations and Measured Performance 148 7.6 Conclusions 150 References 151 8 Combline Filters Implemented in SSS 153 8.1 Introduction 153 8.2 Combline Filters 153 8.3 Design Method 156 8.3.1 Prototype Circuit 156 8.3.2 Equivalent Circuit 157 8.3.3 Input and Output 159 8.3.4 Feasibility 162 8.3.5 Physical Parameters of the Combline Structure 162 8.4 Design Example 165 8.5 Realizations and Measured Performance 168 8.6 Conclusions 169 References 170 PART III NON-MINIMUM-PHASE SYMMETRICAL RESPONSE FILTERS 171 9 Generalized Interdigital Filters with Conditions on Amplitude and Phase 173 9.1 Introduction 173 9.2 Generalized Interdigital Filter 174 9.3 Simultaneous Amplitude and Phase Functions 175 9.3.1 Minimum-Phase Functions with Linear Phase 175 9.3.2 Non-Minimum-Phase Functions with Simultaneous Conditions on the Amplitude and Phase 177 9.3.3 Synthesis of Non-Minimum-Phase Functions with Simultaneous Conditions on the Amplitude and Phase 180 9.4 Design Method 182 9.4.1 Even-Mode Equivalent Circuit 182 9.4.2 Frequency Transformation 186 9.4.3 Physical Parameters of the Interdigital Structure 187 9.5 Design Example 191 9.6 Realizations and Measured Performance 194 9.7 Conclusions 195 References 197 10 Temperature-Stable Narrowband Monomode TE011 Linear-Phase Filters 199 10.1 Introduction 199 10.2 TE011 Filters 200 10.3 Low-Pass Prototype 200 10.3.1 Amplitude 200 10.3.2 Delay 201 10.3.3 Synthesis of the Low-Pass Prototype 202 10.4 Design Method 204 10.4.1 Matching the Coupling 204 10.4.2 Selecting the Cavities 207 10.4.3 Defining the Coupling 208 10.5 Design Example 210 10.6 Realizations and Measured Performance 213 10.6.1 Amplitude and Phase Performance 213 10.6.2 Temperature Performance 214 10.7 Conclusions 215 References 217 PART IV NON-MINIMUM-PHASE ASYMMETRICAL RESPONSE FILTERS 219 11 Asymmetrical Capacitive-Gap Coupled Line Filters 221 11.1 Introduction 221 11.2 Capacitive-Gap Coupled Line Filters 222 11.3 Synthesis of Low-Pass Asymmetrical Generalized Chebyshev Filters 222 11.3.1 In-Line Network 225 11.3.2 Analysis of the In-Line Network 226 11.3.3 Synthesis of the In-Line Network 229 11.3.4 Frequency Transformation 232 11.4 Design Method 233 11.5 Design Example 238 11.6 Realization of the CGCL Filter 243 11.7 Conclusions 244 References 245 12 Asymmetrical Dual-Mode TE102/TE301 Thick Iris Rectangular In-Line Waveguide Filters with Transmission Zeros 247 12.1 Introduction 247 12.2 TE102/TE301 Filters 248 12.3 Synthesis of Low-Pass Asymmetrical Generalized Chebyshev Filters 248 12.3.1 Fundamental Element 249 12.3.2 Analysis of the In-Line Network 250 12.3.3 Synthesis by Simple Extraction Techniques 252 12.3.4 Frequency Transformation 254 12.4 Design Method 256 12.4.1 Equivalent Circuit of Monomode and Bimode Cavities 256 12.4.2 Optimization Approach 256 12.5 Design Example 262 12.6 Realizations and Measured Performance 266 12.6.1 Third-Order Filter with One Transmission Zero 266 12.6.2 Fourth-Order Filter with Two Transmission Zeros 268 12.7 Conclusions 269 References 270 13 Asymmetrical Cylindrical Dual-Mode Waveguide Filters with Transmission Zeros 273 13.1 Introduction 273 13.2 Dual-Mode Cylindrical Waveguide Filters 274 13.3 Synthesis of Low-Pass Asymmetrical Generalized Chebyshev Filters 275 13.3.1 Synthesis From a Cross-Coupled Prototype 275 13.3.2 Extracting the Elements from the Chain Matrix 277 13.3.3 Coupling Graph and Frequency Transformation 281 13.4 Design Method 284 13.4.1 Rotation Matrix 284 13.4.2 Cruciform Iris 286 13.4.3 Physical Parameters of the Irises 290 13.5 Realizations and Measured Performance 292 13.5.1 Fourth-Order Filter with One Transmission Zero on the Left 292 13.5.2 Fourth-Order Filter with Two Ransmission Zeros on the Right 293 13.5.3 Sixth-Order Filter with One Transmission Zero on the Right 295 13.6 Conclusions 296 References 296 14 Asymmetrical Multimode Rectangular Building Block Filters Using Genetic Optimization 299 14.1 Introduction 299 14.2 Multimode Rectangular Waveguide Filters 300 14.3 Optimization-Based Design 302 14.3.1 Genetic Algorithm 302 14.3.2 Example 308 14.4 Realizations 313 14.4.1 Fourth-Order Filter with Two Transmission Zeros 313 14.4.2 Seventh-Order Filter with Four Transmission Zeros 314 14.4.3 Extension to a Tenth-Order Filter with Six Transmission Zeros 318 14.5 Conclusions 320 References 320 Appendix 1: Lossless Systems 323 Appendix 2: Redundant Elements 325 Appendix 3: Modal Analysis of Waveguide Step Discontinuities 328 Appendix 4: Trisections with Unity Inverters on the Inside or on the Outside 338 Appendix 5: Reference Fields and Scattering Matrices for Multimodal Rectangular Waveguide Filters 340 Index 353