Ferran Martín, IEEE Fellow, is a Full Professor of Electronics at Universitat Autònoma de Barcelona (UAB), Spain.

Lei Zhu, IEEE Fellow, is a Full Professor in the Faculty of Science and Technology at the University of Macau, Macau SAR, China.

Jiasheng Hong, IEEE Fellow, is a Full Professor in the Department of Electrical, Electronic and Computer Engineering at Heriot-Watt University, Edinburgh, UK.

Francisco Medina, IEEE Fellow, is a Full Professor of Electromagnetism at Universidad de Sevilla, Seville, Spain

LIST OF CONTRIBUTORS xix

PREFACE xxiii

PART 1 INTRODUCTION 1

1 INTRODUCTION TO BALANCED TRANSMISSION LINES, CIRCUITS, AND NETWORKS 3
Ferran 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 23
Ferran 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 73
Armando 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 93
Teck 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 135
Qing-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 177
Wenquan 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) 249
Jian-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 283
Wei 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 pi-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 353
Ferran 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 373
Xin 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 425
Armando 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...