compact and broadband microstrip antennas

Compact and Broadband Microstrip Antennas. Kin-Lu Wong Copyright c  2002 John Wiley & Sons, Inc. ISBNs: 0-471-41717-3 (Hardback); 0-471-22111-2 (Electronic) Compact and Broadband Microstrip Antennas i P1: FYX/FYX P2: FYX/UKS QC: FYX/UKS T1: FYX PB099-FM PB099-Wong.cls March 28, 2002 15:33 Compact and Broadband Microstrip Antennas KIN-LU WONG A WILEY-INTERSCIENCE PUBLICATION JOHN WILEY & SONS, INC. iii P1: FYX/FYX P2: FYX/UKS QC: FYX/UKS T1: FYX PB099-FM PB099-Wong.cls March 28, 2002 15:33 Designations used by companies to distinguish their products are often claimed as trademarks. In all instances where John Wiley & Sons, Inc., is aware of a claim, the product names appear in initial capital or ALL CAPITAL LETTERS. Readers, however, should contact the appropriate companies for more complete information regarding trademarks and registration. Copyright C  2002 by John Wiley & Sons, Inc., New York. All rights reserved. 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ISBN 0-471-22111-2 This title is also available in print as ISBN 0-471-41717-3. For more information about Wiley products, visit our web site at www.Wiley.com. iv P1: FYX/FYX P2: FYX/UKS QC: FYX/UKS T1: FYX PB099-FM PB099-Wong.cls March 28, 2002 15:33 Contents Preface ix 1 Introduction and Overview 1 1.1 Introduction 1 1.2 Compact Microstrip Antennas 1 1.3 Compact Broadband Microstrip Antennas 7 1.4 Compact Dual-Frequency Microstrip Antennas 8 1.5 Compact Dual-Polarized Microstrip Antennas 10 1.6 Compact Circularly Polarized Microstrip Antennas 10 1.7 Compact Microstrip Antennas with Enhanced Gain 12 1.8 Broadband Microstrip Antennas 12 1.9 Broadband Dual-Frequency and Dual-Polarized Microstrip Antennas 14 1.10 Broadband and Dual-Band Circularly Polarized Microstrip Antennas 15 2 Compact Microstrip Antennas 22 2.1 Introduction 22 2.2 Use of a Shorted Patch with a Thin Dielectric Substrate 23 2.3 Use of a Meandered Patch 26 2.4 Use of a Meandered Ground Plane 28 2.5 Use of a Planar Inverted-L Patch 33 2.6 Use of an Inverted U-Shaped or Folded Patch 39 3 Compact Broadband Microstrip Antennas 45 3.1 Introduction 45 v P1: FYX/FYX P2: FYX/UKS QC: FYX/UKS T1: FYX PB099-FM PB099-Wong.cls March 28, 2002 15:33 vi CONTENTS 3.2 Use of a Shorted Patch with a Thick Air Substrate 46 3.2.1 Probe-Fed Shorted Patch or Planar Inverted-F Antenna (PIFA) 46 3.2.2 Aperture-Coupled Shorted Patch 48 3.2.3 Microstrip-Line-Fed Shorted Patch 50 3.2.4 Capacitively Coupled or L-Probe-Fed Shorted Patch 53 3.3 Use of Stacked Shorted Patches 54 3.4 Use of Chip-Resistor and Chip-Capacitor Loading Technique 55 3.4.1 Design with a Rectangular Patch 55 3.4.2 Design with a Circular Patch 59 3.4.3 Design with a Triangular Patch 70 3.4.4 Design with a Meandered PIFA 76 3.5 Use of a Slot-Loading Technique 78 3.6 Use of a Slotted Ground Plane 79 4 Compact Dual-Frequency and Dual-Polarized Microstrip Antennas 87 4.1 Introduction 87 4.2 Some Recent Advances in Regular-Size Dual-Frequency Designs 88 4.2.1 Dual-Frequency Operation with Same Polarization Planes 88 4.2.2 Dual-Frequency Operation with Orthogonal Polarization Planes 104 4.2.3 Dual-Frequency Feed Network Designs 108 4.3 Compact Dual-Frequency Operation with Same Polarization Planes 111 4.3.1 Design with a Pair of Narrow Slots 112 4.3.2 Design with a Shorted Microstrip Antenna 115 4.3.3 Design with a Triangular Microstrip Antenna 121 4.4 Compact Dual-Frequency Operation 129 4.4.1 Design with a Rectangular Microstrip Antenna 129 4.4.2 Design with a Circular Microstrip Antenna 140 4.4.3 Design with a Triangular Microstrip Antenna 146 4.5 Dual-Band or Triple-Band PIFA 149 4.6 Compact Dual-Polarized Designs 149 4.6.1 Design with a Slotted Square Patch 149 4.6.2 Design with a Slotted Ground Plane 154 4.6.3 Design with a Triangular Patch 156 5 Compact Circularly Polarized Microstrip Antennas 162 5.1 Introduction 162 5.2 Designs with a Cross-Slot of Unequal Arm Lengths 162 5.3 Designs with a Y-Shaped Slot of Unequal Arm Lengths 168 P1: FYX/FYX P2: FYX/UKS QC: FYX/UKS T1: FYX PB099-FM PB099-Wong.cls March 28, 2002 15:33 CONTENTS vii 5.4 Designs with Slits 172 5.4.1 With a Slit 172 5.4.2 With a Pair of Slits 177 5.4.3 With Four Inserted Slits 181 5.5 Designs with Spur Lines 192 5.6 Designs with Truncated Corners 193 5.6.1 With a Triangular Patch 194 5.6.2 With a Square-Ring Patch 194 5.6.3 With a Triangular-Ring Patch 198 5.6.4 With a Slotted Square Patch 201 5.7 Designs with Peripheral Cuts 203 5.8 Designs with a Tuning Stub 205 5.8.1 With a Circular Patch 205 5.8.2 With a Square-Ring Patch 209 5.8.3 With a Triangular Patch 211 5.9 Designs with a Bent Tuning Stub 213 5.10 Compact CP Designs with an Inset Microstrip-Line Feed 215 6 Compact Microstrip Antennas with Enhanced Gain 221 6.1 Introduction 221 6.2 Compact Microstrip Antennas with High-Permittivity Superstrate 221 6.2.1 Gain-Enhanced Compact Broadband Microstrip Antenna 221 6.2.2 Gain-Enhanced Compact Circularly Polarized Microstrip Antenna 223 6.3 Compact Microstrip Antennas with Active Circuitry 225 7 Broadband Microstrip Antennas 232 7.1 Introduction 232 7.2 Use of Additional Microstrip Resonators 233 7.3 Microstrip Antennas with an Air Substrate 236 7.3.1 Design with a Modified Probe Feed 236 7.3.2 Design with a U-Slotted Patch 237 7.3.3 Design with an E-Shaped Patch 241 7.3.4 Design with a Three-Dimensional V-Shaped Patch 249 7.4 Broadband Slot-Loaded Microstrip Antennas 251 7.4.1 Design with a Rectangular Patch 251 7.4.2 Design with a Circular Patch 260 7.5 Broadband Microstrip Antennas with an Integrated Reactive Loading 261 7.5.1 Design with a Rectangular Patch 261 7.5.2 Design with a Circular Patch 263 P1: FYX/FYX P2: FYX/UKS QC: FYX/UKS T1: FYX PB099-FM PB099-Wong.cls March 28, 2002 15:33 viii CONTENTS 7.5.3 Design with a Bow-Tie Patch 267 7.5.4 Design with a Triangular Patch 270 7.6 Broadband Microstrip Antennas with Reduced Cross-Polarization Radiation 273 8 Broadband Dual-Frequency and Dual-Polarized Microstrip Antennas 279 8.1 Introduction 279 8.2 Broadband Dual-Frequency Microstrip Antennas 279 8.2.1 A Two-Element Microstrip Antenna 279 8.2.2 A Three-Dimensional V-Shaped Microstrip Antenna 280 8.3 Broadband Dual-Polarized Microstrip Antennas 282 8.3.1 Use of Two Aperture-Coupled Feeds 282 8.3.2 Use of a Gap-Coupled Probe Feed and an H-Slot Coupled Feed 287 8.3.3 Use of an L-Strip Coupled Feed and an H-Slot Coupled Feed 288 9 Broadband and Dual-Band Circularly Polarized Microstrip Antennas 294 9.1 Introduction 294 9.2 Broadband Single-Feed Circularly Polarized Microstrip Antennas 295 9.3 Broadband Two-Feed Circularly Polarized Microstrip Antennas 298 9.3.1 Use of Two Gap-Coupled Probe Feeds with a Wilkinson Power Divider 298 9.3.2 Use of Two Capacitively Coupled Feeds with a Wilkinson Power Divider 299 9.3.3 Use of Two Capacitively Coupled Feeds with a Branch-Line Coupler 305 9.4 Broadband Four-Feed Circularly Polarized Microstrip Antennas 307 9.5 Dual-Band Circularly Polarized Microstrip Antennas 309 9.5.1 A Probe-Fed Circular Patch with Two Pairs of Arc-Shaped Slots 309 9.5.2 A Probe-Fed Square Patch with a Center Slot and Inserted Slits 312 9.5.3 A Probe-Fed Stacked Elliptic Patch 321 Index 325 P1: FYX/FYX P2: FYX/UKS QC: FYX/UKS T1: FYX PB099-FM PB099-Wong.cls March 28, 2002 15:33 Preface In order to meet the miniaturization requirements of portable communication equip- ment, researchers have given much attention recently to compact microstrip anten- nas. Many related compact designs with broadband dual-frequency operation, dual- polarized radiation, circularly polarized radiation, and enhanced antenna gain have been reported. Many significant advances in improving the inherent narrow operating bandwidth of microstrip antennas have been published in the open literature since 1997. By using presently available techniques, one can easily achieve an impedance bandwidth (1:2 voltage standing wave ratio) of larger than 25% for a probe-fed single- patch microstrip antenna. Other feeding methods such as the use of an aperture- coupled feed, a capacitively coupled feed, or a three-dimensional microstrip tran- sition feed can yield impedance bandwidths greater than 40% with good radiation characteristics for a single-patch microstrip antenna. In addition, various designs for achieving broadband circularly polarized radiation, broadband dual-frequency opera- tion, and broadband dual-polarized radiation have been demonstrated. Taking broad- band circularly polarized radiation as an example, some recently reported designs exhibit a 3-dB axial-ratio bandwidth greater than 40% for a single-patch microstrip antenna. Since 1997, the author and his graduate students at National Sun Yat-Sen University, Kaohsiung, Taiwan, have published more than 100 refereed journal papers on the subject of compact and broadband microstrip antennas. These results along with many other advanced designs reported recently by antenna researchers are scat- tered in many technical journals, and it is the intention of this book to organize these advanced designs in the areas of compact and broadband microstrip antennas. The microstrip antenna designs covered in this book are divided into two groups: compact microstrip antennas and broadband microstrip antennas. The book is organized into nine chapters. Chapter 1 presents an introduction and overview of recent advances in the design of both compact and broadband microstrip antennas. Chapters 2–6 describe in detail advanced designs for compact microstrip antennas, ix P1: FYX/FYX P2: FYX/UKS QC: FYX/UKS T1: FYX PB099-FM PB099-Wong.cls March 28, 2002 15:33 x PREFACE compact broadband microstrip antennas, compact dual-frequency and dual-polarized microstrip antennas, compact circularly polarized microstrip antennas, and compact microstrip antennas with enhanced gain, respectively. Chapters 7–9 are devoted re- spectively to advanced designs for broadband microstrip antennas, broadband dual- frequency and dual-polarized microstrip antennas, and broadband and dual-band cir- cularly polarized microstrip antennas. Chapter 2 introduces recent advances in compact microstrip antennas. Based on recent compact design techniques, such as using a shorted patch, a meandered patch, a meandered ground plane, an inverted U-shaped patch, a planar inverted-L patch, among others, microstrip antenna designs are discussed in the different sections of this chapter. Details of antenna designs and experimental results are presented. Chapter 3 discusses compact broadband microstrip antenna designs. Design tech- niques for achieving broadband operation with a reduced antenna size are described. Related techniques include the use of a shorted patch with a thick air substrate, stacked shorted patches, chip-resistor loading, chip-resistor and chip-capacitor loading, and slot loading in the radiating patch or ground plane. Chapter 4 presents designs for compact dual-frequency and dual-polarized microstrip antennas. Recent advances in regular-size dual-frequency designs are first discussed, and then designs for achieving compact dual-frequency operation with same-polarization and orthogonal polariza- tion planes are described in detail. Both regular-size and compact dual-frequency designs are discussed, which should give the reader a more complete view of recent developments in dual-frequency design. Advances in compact dual-polarized design are also reviewed, and design examples are given. Advances in compact circularly polarized (CP) microstrip antennas are considered in Chapter 5. Examples of compact CP designs, including those using a probe feed, an edge-fed microstrip-line feed, or an inset-microstrip-line feed, are presented. Designs for achieving gain-enhanced compact microstrip antennas are included in Chapter 6. Some design examples for active compact microstrip antennas and gain-enhanced compact circularly polarized microstrip antennas are given. Chapter 7 is devoted to recent advances in broadband microstrip antennas. Advances in broadband microstrip antennas with, for example, additional microstrip resonators, an air or a foam substrate, slot loading, or integrated reactive loading are presented and discussed in detail. Broadband designs with reduced cross-polarization radiation are presented. Chapter 8 presents broadband dual-frequency and dual- polarized microstrip antennas. Various design examples are presented, and design considerations for achieving high isolation and low cross-polarization for broadband dual-polarized radiation are addressed. Finally, in Chapter 9, advances in broadband and dual-band circularly polarized microstrip antennas are discussed. Related broadband designs with single-feed ex- citation, two-feed excitation with a 90 ◦ phase shift, and four-feed excitation with 0 ◦ –90 ◦ –180 ◦ –270 ◦ phase shifts are studied. In addition to obtaining a wide axial-ratio bandwidth, it is shown how to improve CP quality in the entire radiation pattern to achieve wide-angle CP coverage, and related designs are presented. Recent advances in dual-band CP radiation are included in this chapter. P1: FYX/FYX P2: FYX/UKS QC: FYX/UKS T1: FYX PB099-FM PB099-Wong.cls March 28, 2002 15:33 PREFACE xi This book is intended to organize new advanced designs of compact and broadband microstrip antennas, mainly those reported since 1997. Over 100 advanced microstrip antenna designs and their detailed experimental results are included. It is believed that this book can be a very useful design reference on compact and broadband microstrip antennas for antenna scientists and engineers. K IN-L U WONG Kaohsiung, Taiwan [...]... applications of microstrip antennas For this reason, studies to achieve compact and broadband operations of microstrip antennas have greatly increased Much significant progress in the design of compact microstrip antennas with broadband, dual-frequency, dualpolarized, circularly polarized, and gain-enhanced operations have been reported over the past several years In addition, various novel broadband microstrip. .. dual-polarized, and circularly polarized operations have been published in the open literature This book organizes and presents these recently reported novel designs for compact and broadband microstrip antennas 1.2 COMPACT MICROSTRIP ANTENNAS Many techniques have been reported to reduce the size of microstrip antennas at a fixed operating frequency In general, microstrip antennas are half-wavelength structures and. .. Double-folded patch, 5 Dual-band PIFA, see Planar inverted-F antenna (PIFA) Dual-frequency feed network, 108 Dual-frequency microstrip antenna compact, see Compact microstrip antenna with orthogonal polarization planes, 104 with same polarization planes, 88 Dual-polarized microstrip antenna broadband, see Broadband microstrip antenna compact, see Compact microstrip antenna Dual-frequency microstrip array, 101... 1998 74 M C Pan and K L Wong, “A broadband slot-loaded trapezoid microstrip antenna,” Microwave Opt Technol Lett 24, 16–19, Jan 5, 2000 75 J H Lu, C L Tang, and K L Wong, “Novel dual-frequency and broadband designs of single-feed slot-loaded equilateral-triangular microstrip antennas, ” IEEE Trans Antennas Propagat 48, 1048–1054, July 2000 76 K L Wong and J Y Jan, Broadband circular microstrip antenna... see Feed L-shaped slit, see Slit L-strip coupled feed, see Feed Meandered ground plane, see Ground plane Meandered patch, 4, 26, 76, 112 Microstrip antenna broadband, see Broadband microstrip antenna circularly polarized, see Circularly polarized microstrip antenna compact, see Compact microstrip antenna dual-frequency, see Dual-frequency microstrip antenna Notched square patch, 108 Offset circular slot,... Kuo, S T Fang, and T W Chiou, Broadband microstrip antennas with integrated reactive loading,” in Proceedings 1999 Asia Pacific Microwave Conference, pp 352–354 81 H F Pues and A Van de Capelle, “An impedance-matching technique for increasing the bandwidth of microstrip antennas, ” IEEE Trans Antennas Propagat 37, 1345–1354, Nov 1989 82 K W Loi, S Uysai, and M S Leong, “Design of a wideband microstrip bowtie... 29, 95–97, April 20, 2001 26 K L Wong and Y F Lin, “Small broadband rectangular microstrip antenna with chipresistor loading,” Electron Lett 33, 1593–1594, Sept 11, 1997 27 K L Wong and Y F Lin, Microstrip- line-fed compact broadband circular microstrip antenna with chip-resistor loading,” Microwave Opt Technol Lett 17, 53–55, Jan 1998 28 R B Waterhouse, Broadband stacked shorted patch,” Electron Lett... a meandered ground plane can be greater than that of the corresponding conventional microstrip antenna FIGURE 1.7 Geometry of a probe-fed compact microstrip antenna with a meandered ground plane (From Ref 25, c 2001 John Wiley & Sons, Inc.) P1: MRM/SPH PB099-5750F-01 P2: MRM PB099-Wong.cls October 4, 2001 16:47 COMPACT BROADBAND MICROSTRIP ANTENNAS 7 FIGURE 1.8 Geometry of a probe-fed compact microstrip. .. shift to the microstrip antenna; significant cross-polarization reduction of about 5–10 and 12–15 dB in the E-plane and H-plane patterns, respectively, has been achieved [83] Details of the related antenna designs and experimental results are given in Chapter 7 1.9 BROADBAND DUAL-FREQUENCY AND DUAL-POLARIZED MICROSTRIP ANTENNAS Designs of dual-frequency microstrip antennas with impedance bandwidths of... hybrid feeds of a gap-coupled probe feed and an H-slot coupled feed has also been found to be a promising dual-polarized design for achieving high port decoupling [85] Details of typical design examples are included in Chapter 8 1.10 BROADBAND AND DUAL-BAND CIRCULARLY POLARIZED MICROSTRIP ANTENNAS To achieve broadband, single-feed, circularly polarized microstrip antennas, a design with chip-resistor . PREFACE compact broadband microstrip antennas, compact dual-frequency and dual-polarized microstrip antennas, compact circularly polarized microstrip antennas, and compact microstrip antennas. advanced designs for broadband microstrip antennas, broadband dual- frequency and dual-polarized microstrip antennas, and broadband and dual-band cir- cularly polarized microstrip antennas. Chapter. Introduction and Overview 1 1.1 Introduction 1 1.2 Compact Microstrip Antennas 1 1.3 Compact Broadband Microstrip Antennas 7 1.4 Compact Dual-Frequency Microstrip Antennas 8 1.5 Compact Dual-Polarized Microstrip