Microwave Bandpass Filters for Wideband Communications

by Lei Zhu, Sheng Sun, Rui Li

Overview

A Much-Needed Systematic Guide to the Design of (Ultra-)Wideband Bandpass Filters

Ultra-wideband (UWB) technology has attracted a lot of attention in recent years, owing to its numerous applications in high-speed and high-capacity wireless communications. At the same time, conventional synthesis methodologies were shown to be inadequate for bandpass filtering design covering a wide or ultra-wide bandpass. This book responds to the need for a practical guide to emerging design techniques for advanced (ultra-)wideband bandpass filters.

The authors introduce microwave wideband bandpass filter design theory using the multiple-mode resonator (MMR) along with the alternative synthesis design method for wideband bandpass filters, particularly for filters with FCC-defined UWB frequencies from 3.1 to 10.6 GHz. They demonstrate the application of both methods in the design of (ultra-)wideband bandpass filters, showing how to use these methods to implement filters in different frequencies and materials, calculate initial dimensions for various filter configurations, and more.

Special features of this book include:

• Complete design procedures and tabulated design parameters for both MMR and the synthesis design method
• A large number of easy-to-follow design examples, which can be modified by readers to achieve their own design specifications
• Coverage of the basics, including transmission line theories and comparison with the design of conventional narrow-band bandpass filters

Microwave Bandpass Filters for Wideband Communications is an invaluable guide for researchers and engineers wishing to improve their design cycle and filter performance. It is also a useful reference for newcomers to the field, who wish to gain a better understanding of (ultra-)wideband bandpass design theory.

Product Details

ISBN-13:	9781118197974
Publisher:	Wiley
Publication date:	12/28/2011
Series:	Wiley Series in Microwave and Optical Engineering , #232
Sold by:	JOHN WILEY & SONS
Format:	eBook
Pages:	240
File size:	9 MB

About the Author

LEI ZHU, PhD, is Associate Professor at the School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore. Dr. Zhu was the first to introduce an MMR-based filter in 2000, which has since spurred the successful development of a new class of wideband filters with fractional bandwidths larger than 60 percent.

SHENG SUN, PhD, is Research Assistant Professor in the Department of Electrical and Electronic Engineering at The University of Hong Kong.

RUI LI, PhD, is a Research Fellow in the Interconnection and Advanced Packaging Program at Singapore's Institute of Microelectronics. She was the recipient of both the NTU Research and the Ministry of Education Scholarships in Singapore.

Table of Contents

Preface ix

1 Introduction 1

1.1 Background on UWB Technology 2

1.2 UWB Regulations 3

1.2.1 FCC Radiation Masks 3

1.2.2 ECC Radiation Masks 4

1.2.3 UWB Definition and Bandwidth 7

1.3 UWB Bandpass Filters 8

1.4 Organization of the Book 11

References 13

2 Transmission Line Concepts and Networks 18

2.1 Introduction 18

2.2 Transmission Line Theory 19

2.2.1 Basic Transmission Line Model 19

2.2.2 Lossless Terminated Transmission Lines 21

2.3 Microwave Network Parameters 26

2.3.1 Scattering Parameters for Two-Port Network 26

2.3.2 [Z] and [Y] Matrices 30

2.3.3 ABCD Parameters 33

2.3.4 Conversions between S-, Z-, Y-, and ABCD-Matrix Parameters 38

2.4 Relative Theories of Network Analysis 42

2.4.1 Even-and Odd-Mode Network Analysis 42

2.4.2 Image Parameter Method 47

2.5 Summary 52

References 52

3 Conventional Parallel-Coupled Line Filter 53

3.1 Introduction 53

3.2 Lumped-Element Lowpass Filter Prototype 54

3.2.1 Maximally Flat and Chebyshev Characteristics 54

3.2.2 Lumped-Element Ladder Network 56

3.3 Impedance and Frequency Transformation 65

3.3.1 Lowpass to Lowpass Transformation 66

3.3.2 Lowpass to Highpass Transformation 66

3.3.3 Lowpass to Bandpass Transformation 67

3.3.4 Lowpass to Bandstop Transformation 68

3.4 Immittance Inverters 70

3.5 Lowpass Prototype Filter with Immittance Inverter 71

3.6 Parallel-Coupled Line Bandpass Filter 76

3.7 Summary 84

ferences 84

4 Planar Transmission Line Resonators 85

4.1 Introduction 85

4.2 Uniform Impedance Resonator 87

4.2.1 Short-Circuited λ_g/2 Transmission Line 87

4.2.2 Open-Circuited λ_g/2 Transmission Line 89

4.2.3 Short-Circuited λ_g/4 Transmission Line 91

4.2.4 Open-Circuited λ_g/4 Transmission Line 93

4.3 Stepped Impedance Resonators 94

4.3.1 Fundamental Properties of SIR 95

4.3.2 Slope Parameters of SIR 101

4.3.3 Design of the Parallel-Coupled Line Bandpass Filters with SIR 102

4.4 Multiple-Mode Resonator 104

4.4.1 Open-Circuited Multiple-Mode Resonator 104

4.4.2 Short-Circuited Multiple-Mode Resonator 108

4.4.3 Design of the Parallel-Coupled Line Bandpass Filters with MMRs 109

4.5 Summary 113

References 114

5 MMR-Based UWB Bandpass Filters 116

5.1 Introduction 116

5.2 An Initial MMR-Based UWB Bandpass Filter 118

5.3 UWB Bandpass Filters with Varied Geometries 121

5.3.1 Aperture-Backed PCML 121

5.3.2 Broadside Microstrip/CPW 122

5.3.3 Inductive Coupling Element on CPW 125

5.4 UWB Filters with Improved Out-of-Band Performance 130

5.4.1 Capacitive-Ended Interdigital Coupled Lines 130

5.4.2 Coupling between Two Feed Lines 134

5.4.3 Stub-Loaded MMR 136

5.4.4 Lowpass Embedded MMR 140

5.5 UWB Bandpass Filter with a Notch Band 142

5.6 Summary 146

References 146

6 Synthesis approach for UWB Filters 149

6.1 Introduction 149

6.2 Transfer Function 150

6.3 Transmission Line Network with Pure Shunt/Series Stubs 152

6.4 Transmission Line Network with Hybrid Series and Shunt Stubs 163

6.5 MMR-Based UWB Filter with Parallel-Coupled Lines 178

6.6 Summary 187

References 187

7 Other Types of UWB Filters 188

7.1 Introduction 188

7.2 UWB Filters with Highpass and Lowpass Filters 188

7.3 UWB Filters with Optimum Shunt Short-Circuited Stubs 191

7.3.1 UWB Filter with Extended Upper Stopband 192

7.3.2 UWB Filter with Enhanced Selectivity 194

7.4 UWB Filters with Quasi-Lumped Elements 195

7.4.1 UWB Filter Implemented with Suspended Strip Line 195

7.4.2 UWB Filter Implemented on Liquid Crystal Polymer (LCP) 195

7.5 UWB Filters with Composite CPW and Microstrip Structure 197

7.6 UWB Filter with Microstrip Ring Resonator 199

7.7 UWB Filter using Multilayer Structures 203

7.8 UWB Filter with Substrate Integrated Waveguide (SIW) 205

7.9 UWB Filter with Notch Band 207

7.10 Summary 210

References 210

Index 214