LIST OF CONTRIBUTORS xix PREFACE xxiii PART 1 INTRODUCTION 1 1 INTRODUCTION TO BALANCED TRANSMISSION LINES, CIRCUITS, AND NETWORKS 3Ferran Martín, Jordi Naqui, Francisco Medina, Lei Zhu, and Jiasheng Hong 1.1 Introduction 3 1.2 Balanced Versus Single-Ended Transmission Lines and Circuits 4 1.3 Common-Mode Noise 5 1.4 Fundamentals of Differential Transmission Lines 6 1.4.1 Topology 6 1.4.2 Propagating Modes 8 1.4.2.1 Even and Odd Mode 8 1.4.2.2 Common and Differential Mode 11 1.5 Scattering Parameters 13 1.5.1 Single-Ended S-Parameters 13 1.5.2 Mixed-Mode S-Parameters 16 1.6 Summary 19 References 19 PART 2 BALANCED TRANSMISSION LINES WITH COMMON-MODE NOISE SUPPRESSION 21 2 STRATEGIES FOR COMMON-MODE SUPPRESSION IN BALANCED LINES 23Ferran Martín, Paris Vélez, Armando Fernández-Prieto, Jordi Naqui, Francisco Medina, and Jiasheng Hong 2.1 Introduction 23 2.2 Selective Mode Suppression in Differential Transmission Lines 25 2.3 Common-Mode Suppression Filters Based on Patterned Ground Planes 27 2.3.1 Common-Mode Filter Based on Dumbbell-Shaped Patterned Ground Plane 27 2.3.2 Common-Mode Filter Based on Complementary Split Ring Resonators (CSRRs) 30 2.3.3 Common-Mode Filter Based on Defected Ground Plane Artificial Line 40 2.3.4 Common-Mode Filter Based on C-Shaped Patterned Ground Structures 44 2.4 Common-Mode Suppression Filters Based on Electromagnetic Bandgaps (EBGs) 49 2.4.1 Common-Mode Filter Based on Nonuniform Coupled Lines 50 2.4.2 Common-Mode Filter Based on Uniplanar Compact Photonic Bandgap (UC-PBG) Structure 55 2.5 Other Approaches for Common-Mode Suppression 55 2.6 Comparison of Common-Mode Filters 60 2.7 Summary 61 Appendix 2.A: Dispersion Relation for Common-Mode Rejection Filters with Coupled CSRRs or DS-CSRRs 61 Appendix 2.B: Dispersion Relation for Common-Mode Rejection Filters with Coupled Patches Grounded through Inductive Strips 64 References 65 3 COUPLED-RESONATOR BALANCED BANDPASS FILTERS WITH COMMON-MODE SUPPRESSION DIFFERENTIAL LINES 73Armando Fernández-Prieto, Jordi Naqui, Jesús Martel, Ferran Martín, and Francisco Medina 3.1 Introduction 73 3.2 Balanced Coupled-Resonator Filters 74 3.2.1 Single-Band Balanced Bandpass Filter Based on Folded Stepped-Impedance Resonators 75 3.2.2 Balanced Filter Loaded with Common-Mode Rejection Sections 79 3.2.3 Balanced Dual-Band Bandpass Filter Loaded with Common-Mode Rejection Sections 82 3.3 Summary 88 References 88 PART 3 WIDEBAND AND ULTRA-WIDEBAND (UWB) BALANCED BAND PASS FILTERS WITH INTRINSIC COMMON-MODE SUPPRESSION 91 4 WIDEBAND AND UWB BALANCED BANDPASS FILTERS BASED ON BRANCH-LINE TOPOLOGY 93Teck Beng Lim and Lei Zhu 4.1 Introduction 93 4.2 Branch-Line Balanced Wideband Bandpass Filter 97 4.3 Balanced Bandpass Filter for UWB Application 105 4.4 Balanced Wideband Bandpass Filter with Good Common-Mode Suppression 111 4.5 Highly Selective Balanced Wideband Bandpass Filters 116 4.6 Summary 131 References 131 5 WIDEBAND AND UWB COMMON-MODE SUPPRESSED DIFFERENTIAL-MODE FILTERS BASED ON COUPLED LINE SECTIONS 135Qing-Xin Chu, Shi-Xuan Zhang, and Fu-Chang Chen 5.1 Balanced UWB Filter by Combining UWB BPF with UWB BSF 135 5.2 Balanced Wideband Bandpass Filter Using Coupled Line Stubs 142 5.3 Balanced Wideband Filter Using Internal Cross-Coupling 148 5.4 Balanced Wideband Filter Using Stub-Loaded Ring Resonator 155 5.5 Balanced Wideband Filter Using Modified Coupled Feed Lines and Coupled Line Stubs 161 5.6 Summary 173 References 174 6 WIDEBAND DIFFERENTIAL CIRCUITS USING T-SHAPED STRUCTURES AND RING RESONATORS 177Wenquan Che and Wenjie Feng 6.1 Introduction 177 6.2 Wideband Differential Bandpass Filters Using T-Shaped Resonators 179 6.2.1 Mixed-Mode S-Parameters for Four-Port Balanced Circuits 179 6.2.2 T-Shaped Structures with Open/Shorted Stubs 184 6.2.2.1 T-Shaped Structure with Shorted Stubs 184 6.2.2.2 T-Shaped Structure with Open Stubs 185 6.2.3 Wideband Bandpass Filters without Cross Coupling 187 6.2.3.1 Differential-Mode Excitation 189 6.2.3.2 Common-Mode Excitation 191 6.2.4 Wideband Bandpass Filter with Cross Coupling 193 6.3 Wideband Differential Bandpass Filters Using Half-/Full-Wavelength Ring Resonators 201 6.3.1 Differential Filter Using Half-Wavelength Ring Resonators 201 6.3.2 Differential Filter Using Full-Wavelength Ring Resonators 206 6.3.3 Differential Filter Using Open/Shorted Coupled Lines 215 6.3.4 Comparisons of Several Wideband Balanced Filters Based on Different Techniques 220 6.4 Wideband Differential Networks Using Marchand Balun 223 6.4.1 S-Parameter for Six-Port Differential Network 223 6.4.2 Wideband In-Phase Differential Network 227 6.4.3 Wideband Out-of-Phase Differential Network 236 6.5 Summary 244 References 245 7 UWB AND NOTCHED-BAND UWB DIFFERENTIAL FILTERS USING MULTILAYER AND DEFECTED GROUND STRUCTURES (DGSS) 249Jian-Xin Chen, Li-Heng Zhou, and Quan Xue 7.1 Conventional Multilayer Microstrip-to-Slotline Transition (MST) 250 7.2 Differential MST 251 7.2.1 Differential MST with a Two-Layer Structure 251 7.2.2 Differential MST with Three-Layer Structure 252 7.3 UWB Differential Filters Based on the MST 253 7.3.1 Differential Wideband Filters Based on the Conventional MST 253 7.3.2 Differential Wideband Filters Based on the Differential MST 255 7.4 Differential Wideband Filters Based on the Strip-Loaded Slotline Resonator 262 7.4.1 Differential Wideband Filters Using Triple-Mode Slotline Resonator 265 7.4.2 Differential Wideband Filters Using Quadruple-Mode Slotline Resonator 267 7.5 UWB Differential Notched-Band Filter 270 7.5.1 UWB Differential Notched-Band Filter Based on the Traditional MST 270 7.5.2 UWB Differential Notched-Band Filter Based on the Differential MST 272 7.6 Differential UWB Filters with Enhanced Stopband Suppression 277 7.7 Summary 280 References 281 8 APPLICATION OF SIGNAL INTERFERENCE TECHNIQUE TO THE IMPLEMENTATION OF WIDEBAND DIFFERENTIAL FILTERS 283Wei Qin and Quan Xue 8.1 Basic Concept of the Signal Interference Technique 283 8.1.1 Fundamental Theory 284 8.1.2 One Filter Example Based on Ring Resonator 287 8.1.3 Simplified Circuit Model 288 8.2 Signal Interference Technique for Wideband Differential Filters 290 8.2.1 Circuit Model of Wideband Differential Bandpass Filter 290 8.2.2 S-Matrix for Differential Bandpass Filters 292 8.3 Several Designs of Wideband Differential Bandpass Filters 293 8.3.1 Differential Bandpass Filter Based on Wideband Marchand Baluns 293 8.3.2 Differential Bandpass Filter Based on π-Type UWB 180 Phase Shifters 299 8.3.3 Differential Bandpass Filter Based on DSPSL UWB 180 Phase Inverter 302 8.3.3.1 Differential-Mode Analysis 305 8.3.3.2 Common-Mode Analysis 305 8.3.3.3 Filter Design and Measurement 308 8.4 Summary 308 References 309 9 WIDEBAND BALANCED FILTERS BASED ON MULTI-SECTION MIRRORED STEPPED IMPEDANCE RESONATORS (SIRs) 311 Ferran Martín, Jordi Selga, Paris Vélez, Marc Sans, Jordi Bonache, Ana Rodríguez, Vicente E. Boria, Armando Fernández-Prieto, and Francisco Medina 9.1 Introduction 311 9.2 The Multi-Section Mirrored Stepped Impedance Resonator (SIR) 312 9.3 Wideband Balanced Bandpass Filters Based on 7-Section Mirrored SIRs Coupled Through Admittance Inverters 317 9.3.1 Finding the Optimum Filter Schematic 319 9.3.2 Layout Synthesis 325 9.3.2.1 Resonator Synthesis 325 9.3.2.2 Determination of the Line Width 327 9.3.2.3 Optimization of the Line Length (Filter Cell Synthesis) 327 9.3.3 A Seventh-Order Filter Example 330 9.3.4 Comparison with Other Approaches 334 9.4 Compact Ultra-Wideband (UWB) Balanced Bandpass Filters Based on 5-Section Mirrored SIRs and Patch Capacitors 336 9.4.1 Topology and Circuit Model of the Series Resonators 337 9.4.2 Filter Design 341 9.4.3 Comparison with Other Approaches 345 9.5 Summary 346 Appendix 9.A: General Formulation of Aggressive Space Mapping (ASM) 347 References 349 10 METAMATERIAL-INSPIRED BALANCED FILTERS 353Ferran Martín, Paris Vélez, Ali Karami-Horestani, Francisco Medina, and Christophe Fumeaux 10.1 Introduction 353 10.2 Balanced Bandpass Filters Based on Open Split Ring ResonatorS (OSRRS) and Open Complementary Split Ring Resonators (OCSRRS) 354 10.2.1 Topology of the OSRR and OCSRR 354 10.2.2 Filter Design and Illustrative Example 356 10.3 Balanced Filters Based on S-Shaped Complementary Split Ring Resonators (S-CSRRs) 363 10.3.1 Principle for Balanced Bandpass Filter Design and Modeling 365 10.3.2 Illustrative Example 367 10.4 Summary 369 References 369 11 WIDEBAND BALANCED FILTERS ON SLOTLINE RESONATOR WITH INTRINSIC COMMON-MODE REJECTION 373Xin Guo, Lei Zhu, and Wen Wu 11.1 Introduction 373 11.2 Wideband Balanced Bandpass Filter on Slotline MMR 375 11.2.1 Working Mechanism 375 11.2.2 Synthesis Method 378 11.2.3 Geometry and Layout 382 11.2.4 Fabrication and Experimental Verification 388 11.3 Wideband Balanced BPF on Strip-Loaded Slotline Resonator 392 11.3.1 Strip-Loaded Slotline Resonator 392 11.3.2 Wideband Balanced Bandpass Filters 396 11.3.2.1 Wideband Balanced BPF on Strip-Loaded Triple-Mode Slotline Resonator 397 11.3.2.2 Wideband Balanced BPF on Strip-Loaded Quadruple-Mode Slotline Resonator 403 11.4 Wideband Balanced Bandpass Filter on Hybrid MMR 408 11.4.1 Hybrid MMR 408 11.4.2 Wideband Balanced Bandpass Filters 416 11.5 Summary 420 References 420 PART 4 NARROWBAND AND DUAL-BAND BALANCED BANDPASS FILTERS WITH INTRINSIC COMMON-MODE SUPPRESSION 423 12 NARROWBAND COUPLED-RESONATOR BALANCED BANDPASS FILTERS AND DIPLEXERS 425Armando Fernández-Prieto, Francisco Medina, and Jesús Martel 12.1 Introduction 425 12.2 Coupled-Resonator Balanced Filters with Intrinsic Common-Mode Rejection 426 12.2.1 Loop and SIR Resonator Filters with Mixed Coupling 427 12.2.1.1 Quasi-elliptic Response BPF: First Example 428 12.2.1.2 Quasi-elliptic Response BPF: Second Example 434 12.2.2 Magnetically Coupled Open-Loop and FSIR Balanced Filters 439 12.2.2.1 Filters with Magnetic Coupling: First Example 439 12.2.2.2 Filters with Magnetic Coupling: Second Example 447 12.2.3 Interdigital Line Resonators Filters 449 12.2.3.1 ILR Filter Design Example 450 12.2.4 Dual-Mode and Dual-Behavior Resonators for Balanced Filter Design 451 12.2.4.1 Dual-Mode Square Patch Resonator Filters 453 12.2.4.2 Filters Based on Dual-Behavior Resonators 458 12.2.5 LTCC-Based Multilayer Balanced Filter 464 12.2.6 Balanced Bandpass Filters Based on Dielectric Resonators 466 12.3 Loaded Resonators for Common-Mode Suppression Improvement 469 12.3.1 Capacitively, Inductively, and Resistively Center-Loaded Resonators 470 12.3.1.1 Open-Loop UIR-Loaded Filter 470 12.3.1.2 Folded SIR Loaded Filter 476 12.3.2 Filters with Defected Ground Structures (DGS) 484 12.3.2.1 Control of the Transmission Zeros 488 12.3.3 Multilayer Loaded Resonators 490 12.3.3.1 Design Example 492 12.4 Coupled Line Balanced Bandpass Filter 493 12.4.1 Type-II Design Example 495 12.5 Balanced Diplexers 499 12.5.1 Unbalanced-to-Balanced Diplexer Based on Uniform Impedance Stub-Loaded Coupled Resonators 500 12.5.1.1 Resonator Geometry 500 12.5.1.2 Unbalanced-to-Balanced Diplexer Design 502 12.5.2 Example Two: Balanced-to-Balanced Diplexer Based on UIRs and Short-Ended Parallel-Coupled Lines 505 12.6 Summary 508 References 510 13 DUAL-BAND BALANCED FILTERS BASED ON LOADED AND COUPLED RESONATORS 515Jin Shi and Quan Xue 13.1 Dual-Band Balanced Filter with Loaded Uniform Impedance Resonators 516 13.1.1 Center-Loaded Uniform Impedance Resonator 516 13.1.2 Dual-Band Balanced Filter Using the Uniform Impedance Resonator with Center-Loaded Lumped Elements 520 13.1.3 Dual-Band Balanced Filter Using Stub-Loaded Uniform Impedance Resonators 526 13.2 Dual-Band Balanced Filter with Loaded Stepped-Impedance Resonators 528 13.2.1 Center-Loaded Stepped-Impedance Resonator 528 13.2.2 Dual-Band Balanced Filter Using Stepped-Impedance Resonators with Center-Loaded Lumped Elements 531 13.2.3 Dual-Band Balanced Filter Using Stub-Loaded Stepped-Impedance Resonators 535 13.3 Dual-Band Balanced Filter Based on Coupled Resonators 538 13.3.1 Dual-Band Balanced Filter with Coupled Stepped-Impedance Resonators 538 13.3.2 Dual-Band Balanced Filter with Coupled Stub-Loaded Short-Ended Resonators 542 13.4 Summary 546 References 547 14 DUAL-BAND BALANCED FILTERS IMPLEMENTED IN SUBSTRATE INTEGRATED WAVEGUIDE (SIW) TECHNOLOGY 549Wen Wu, Jianpeng Wang, and Chunxia Zhou 14.1 Substrate Integrated Waveguide (SIW) Cavity 550 14.2 Closely Proximate Dual-Band Balanced Filter Design 551 14.3 Dual-Band Balanced Filter Design Utilizing High-Order Modes in SIW Cavities 555 14.4 Summary 563 References 563 PART 5 OTHER BALANCED CIRCUITS 565 15 BALANCED POWER DIVIDERS/COMBINERS 567Lin-Sheng Wu, Bin Xia, and Jun-Fa Mao 15.1 Introduction 567 15.2 Balanced-to-Balanced Wilkinson Power Divider with Microstrip Line 569 15.2.1 Mixed-Mode Analysis 569 15.2.1.1 Mixed-Mode Scattering Matrix of a Balanced-to-Balanced Power Divider 569 15.2.1.2 Constraint Rules of Balanced-to-Balanced Power Divider 571 15.2.1.3 Odd- and Even-Mode Scattering Matrices of Balanced-to-Balanced Power Divider 572 15.2.2 A Transmission-Line Balanced-to-Balanced Power Divider 572 15.2.2.1 Even-Mode Circuit Model 572 15.2.2.2 Odd-Mode Circuit Model 573 15.2.2.3 Scattering Matrix of the Balanced-to-Balanced Power Divider 575 15.2.3 Theoretical Result 575 15.2.4 Simulated and Measured Results 576 15.3 Balanced-to-Balanced Gysel Power Divider with Half-Mode Substrate Integrated Waveguide (SIW) 580 15.3.1 Conversion from Single-Ended Circuit to Balanced Form 580 15.3.2 Half-Mode SIW Ring Structure 581 15.3.3 Results and Discussion 583 15.4 Balanced-to-Balanced Gysel Power Divider with Arbitrary Power Division 585 15.4.1 Analysis and Design 585 15.4.2 Results and Discussion 587 15.5 Balanced-to-Balanced Gysel Power Divider with Bandpass Filtering Response 590 15.5.1 Coupled-Resonator Circuit Model 590 15.5.2 Realization in Transmission Lines 591 15.5.2.1 Internal Coupling Coefficient 592 15.5.2.2 External Q Factor 594 15.5.3 Results and Discussion 595 15.6 Filtering Balanced-to-Balanced Power Divider with Unequal Power Division 598 15.7 Dual-Band Balanced-to-Balanced Power Divider 599 15.7.1 Analysis and Design 599 15.7.2 Results and Discussion 601 15.8 Summary 603 References 603 16 DIFFERENTIAL-MODE EQUALIZERS WITH COMMON-MODE FILTERING 607Tzong-Lin Wu and Chiu-Chih Chou 16.1 Introduction 607 16.2 Design Considerations 610 16.2.1 Equalizer Design 610 16.2.2 Common-Mode Filter Design 612 16.3 First Design 613 16.3.1 Proposed Topology 613 16.3.2 Odd-Mode Analysis 616 16.3.2.1 Equalizer Optimization in Time Domain 617 16.3.3 Even-Mode Analysis 623 16.3.4 Measurement Validation 628 16.4 Second Design 633 16.4.1 Proposed Circuit and Analysis 633 16.4.2 Realization and Measurement 637 16.4.2.1 Realization 637 16.4.2.2 Common-Mode Noise Suppression 638 16.4.2.3 Differential-Mode Equalization 640 16.5 Summary 641 References 641 INDEX 645

This book presents and discusses strategies for the design and implementation of common-mode suppressed balanced microwave filters, including narrowband, wideband, and ultra-wideband filters This book examines differential-mode, or balanced, microwave filters by discussing several implementations of practical realizations of these passive components. Topics covered include selective mode suppression, designs based on distributed and semi-lumped approaches, multilayer technologies, defect ground structures, coupled resonators, metamaterials, interference techniques, and substrate integrated waveguides, among others. Divided into five parts, Balanced Microwave Filters begins with an introduction that presents the fundamentals of balanced lines, circuits, and networks. Part 2 covers balanced transmission lines with common-mode noise suppression, including several types of common-mode filters and the application of such filters to enhance common-mode suppression in balanced bandpass filters. Next, Part 3 examines wideband and ultra-wideband (UWB) balanced bandpass filters with intrinsic common-mode suppression. Narrowband and dual-band balanced bandpass filters with intrinsic common-mode suppression are discussed in Part 4. Finally, Part 5 covers other balanced circuits, such as balanced power dividers and combiners, and differential-mode equalizers with common-mode filtering. In addition, the book: Explores a research topic of increasing interest due to the growing demand of balanced transmission lines and circuits in modern communication systemsIncludes contributions from prominent worldwide experts in the fieldProvides readers with the necessary knowledge to analyze and synthesize balanced filters and circuits Balanced Microwave Filters is an important text for R&D engineers, professionals, and specialists working on the topic of microwave filters. Post graduate students and Masters students in the field of microwave engineering and wireless communications, especially those involved in courses related to microwave filters, and balanced filters and circuits will also find it to be a vital resource.