Compact and Broadband Microstrip Antennas

340 Pages·2002·6.65 MB·English

by  Kin-Lu Wong

CompactandBroadbandMicrostripAntennas.Kin-LuWong
Copyright(cid:2)c 2002JohnWiley&Sons,Inc.
ISBNs:0-471-41717-3(Hardback);0-471-22111-2(Electronic)
Compact and
Broadband
Microstrip Antennas
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Compact and
Broadband
Microstrip Antennas
KIN-LU WONG
AWILEY-INTERSCIENCEPUBLICATION
JOHN WILEY & SONS, INC.
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Contents
Preface ix
1 IntroductionandOverview 1
1.1 Introduction 1
1.2 CompactMicrostripAntennas 1
1.3 CompactBroadbandMicrostripAntennas 7
1.4 CompactDual-FrequencyMicrostripAntennas 8
1.5 CompactDual-PolarizedMicrostripAntennas 10
1.6 CompactCircularlyPolarizedMicrostripAntennas 10
1.7 CompactMicrostripAntennaswithEnhancedGain 12
1.8 BroadbandMicrostripAntennas 12
1.9 BroadbandDual-FrequencyandDual-Polarized
MicrostripAntennas 14
1.10 BroadbandandDual-BandCircularlyPolarized
MicrostripAntennas 15
2 CompactMicrostripAntennas 22
2.1 Introduction 22
2.2 UseofaShortedPatchwithaThinDielectricSubstrate 23
2.3 UseofaMeanderedPatch 26
2.4 UseofaMeanderedGroundPlane 28
2.5 UseofaPlanarInverted-LPatch 33
2.6 UseofanInvertedU-ShapedorFoldedPatch 39
3 CompactBroadbandMicrostripAntennas 45
3.1 Introduction 45
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vi CONTENTS
3.2 UseofaShortedPatchwithaThickAirSubstrate 46
3.2.1 Probe-FedShortedPatchorPlanarInverted-F
Antenna(PIFA) 46
3.2.2 Aperture-CoupledShortedPatch 48
3.2.3 Microstrip-Line-FedShortedPatch 50
3.2.4 CapacitivelyCoupledorL-Probe-FedShortedPatch 53
3.3 UseofStackedShortedPatches 54
3.4 UseofChip-ResistorandChip-CapacitorLoadingTechnique 55
3.4.1 DesignwithaRectangularPatch 55
3.4.2 DesignwithaCircularPatch 59
3.4.3 DesignwithaTriangularPatch 70
3.4.4 DesignwithaMeanderedPIFA 76
3.5 UseofaSlot-LoadingTechnique 78
3.6 UseofaSlottedGroundPlane 79
4 CompactDual-FrequencyandDual-Polarized
MicrostripAntennas 87
4.1 Introduction 87
4.2 SomeRecentAdvancesinRegular-SizeDual-Frequency
Designs 88
4.2.1 Dual-FrequencyOperationwithSame
PolarizationPlanes 88
4.2.2 Dual-FrequencyOperationwithOrthogonal
PolarizationPlanes 104
4.2.3 Dual-FrequencyFeedNetworkDesigns 108
4.3 CompactDual-FrequencyOperationwithSame
PolarizationPlanes 111
4.3.1 DesignwithaPairofNarrowSlots 112
4.3.2 DesignwithaShortedMicrostripAntenna 115
4.3.3 DesignwithaTriangularMicrostripAntenna 121
4.4 CompactDual-FrequencyOperation 129
4.4.1 DesignwithaRectangularMicrostripAntenna 129
4.4.2 DesignwithaCircularMicrostripAntenna 140
4.4.3 DesignwithaTriangularMicrostripAntenna 146
4.5 Dual-BandorTriple-BandPIFA 149
4.6 CompactDual-PolarizedDesigns 149
4.6.1 DesignwithaSlottedSquarePatch 149
4.6.2 DesignwithaSlottedGroundPlane 154
4.6.3 DesignwithaTriangularPatch 156
5 CompactCircularlyPolarizedMicrostripAntennas 162
5.1 Introduction 162
5.2 DesignswithaCross-SlotofUnequalArmLengths 162
5.3 DesignswithaY-ShapedSlotofUnequalArmLengths 168
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CONTENTS vii
5.4 DesignswithSlits 172
5.4.1 WithaSlit 172
5.4.2 WithaPairofSlits 177
5.4.3 WithFourInsertedSlits 181
5.5 DesignswithSpurLines 192
5.6 DesignswithTruncatedCorners 193
5.6.1 WithaTriangularPatch 194
5.6.2 WithaSquare-RingPatch 194
5.6.3 WithaTriangular-RingPatch 198
5.6.4 WithaSlottedSquarePatch 201
5.7 DesignswithPeripheralCuts 203
5.8 DesignswithaTuningStub 205
5.8.1 WithaCircularPatch 205
5.8.2 WithaSquare-RingPatch 209
5.8.3 WithaTriangularPatch 211
5.9 DesignswithaBentTuningStub 213
5.10 CompactCPDesignswithanInset
Microstrip-LineFeed 215
6 CompactMicrostripAntennaswithEnhancedGain 221
6.1 Introduction 221
6.2 CompactMicrostripAntennaswithHigh-Permittivity
Superstrate 221
6.2.1 Gain-EnhancedCompactBroadband
MicrostripAntenna 221
6.2.2 Gain-EnhancedCompactCircularlyPolarized
MicrostripAntenna 223
6.3 CompactMicrostripAntennaswithActiveCircuitry 225
7 BroadbandMicrostripAntennas 232
7.1 Introduction 232
7.2 UseofAdditionalMicrostripResonators 233
7.3 MicrostripAntennaswithanAirSubstrate 236
7.3.1 DesignwithaModifiedProbeFeed 236
7.3.2 DesignwithaU-SlottedPatch 237
7.3.3 DesignwithanE-ShapedPatch 241
7.3.4 DesignwithaThree-DimensionalV-ShapedPatch 249
7.4 BroadbandSlot-LoadedMicrostripAntennas 251
7.4.1 DesignwithaRectangularPatch 251
7.4.2 DesignwithaCircularPatch 260
7.5 BroadbandMicrostripAntennaswithanIntegrated
ReactiveLoading 261
7.5.1 DesignwithaRectangularPatch 261
7.5.2 DesignwithaCircularPatch 263
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viii CONTENTS
7.5.3 DesignwithaBow-TiePatch 267
7.5.4 DesignwithaTriangularPatch 270
7.6 BroadbandMicrostripAntennaswithReduced
Cross-PolarizationRadiation 273
8 BroadbandDual-FrequencyandDual-Polarized
MicrostripAntennas 279
8.1 Introduction 279
8.2 BroadbandDual-FrequencyMicrostripAntennas 279
8.2.1 ATwo-ElementMicrostripAntenna 279
8.2.2 AThree-DimensionalV-ShapedMicrostripAntenna 280
8.3 BroadbandDual-PolarizedMicrostripAntennas 282
8.3.1 UseofTwoAperture-CoupledFeeds 282
8.3.2 UseofaGap-CoupledProbeFeedandanH-Slot
CoupledFeed 287
8.3.3 UseofanL-StripCoupledFeedandanH-Slot
CoupledFeed 288
9 BroadbandandDual-BandCircularlyPolarized
MicrostripAntennas 294
9.1 Introduction 294
9.2 BroadbandSingle-FeedCircularlyPolarized
MicrostripAntennas 295
9.3 BroadbandTwo-FeedCircularlyPolarizedMicrostripAntennas 298
9.3.1 UseofTwoGap-CoupledProbeFeedswithaWilkinson
PowerDivider 298
9.3.2 UseofTwoCapacitivelyCoupledFeedswithaWilkinson
PowerDivider 299
9.3.3 UseofTwoCapacitivelyCoupledFeedswith
aBranch-LineCoupler 305
9.4 BroadbandFour-FeedCircularlyPolarized
MicrostripAntennas 307
9.5 Dual-BandCircularlyPolarizedMicrostripAntennas 309
9.5.1 AProbe-FedCircularPatchwithTwoPairs
ofArc-ShapedSlots 309
9.5.2 AProbe-FedSquarePatchwithaCenterSlot
andInsertedSlits 312
9.5.3 AProbe-FedStackedEllipticPatch 321
Index 325
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Preface
Inordertomeettheminiaturizationrequirementsofportablecommunicationequip-
ment, researchers have given much attention recently to compact microstrip anten-
nas.Manyrelatedcompactdesignswithbroadbanddual-frequencyoperation,dual-
polarized radiation, circularly polarized radiation, and enhanced antenna gain have
beenreported.Manysignificantadvancesinimprovingtheinherentnarrowoperating
bandwidth of microstrip antennas have been published in the open literature since
1997.Byusingpresentlyavailabletechniques,onecaneasilyachieveanimpedance
bandwidth(1:2voltagestandingwaveratio)oflargerthan25%foraprobe-fedsingle-
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
characteristicsforasingle-patchmicrostripantenna.Inaddition,variousdesignsfor
achievingbroadbandcircularlypolarizedradiation,broadbanddual-frequencyopera-
tion,andbroadbanddual-polarizedradiationhavebeendemonstrated.Takingbroad-
band circularly polarized radiation as an example, some recently reported designs
exhibita3-dBaxial-ratiobandwidthgreaterthan40%forasingle-patchmicrostrip
antenna.
Since 1997, the author and his graduate students at National Sun Yat-Sen
University,Kaohsiung,Taiwan,havepublishedmorethan100refereedjournalpapers
on the subject of compact and broadband microstrip antennas. These results along
withmanyotheradvanceddesignsreportedrecentlybyantennaresearchersarescat-
teredinmanytechnicaljournals,anditistheintentionofthisbooktoorganizethese
advanceddesignsintheareasofcompactandbroadbandmicrostripantennas.
Themicrostripantennadesignscoveredinthisbookaredividedintotwogroups:
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,
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x PREFACE
compactbroadbandmicrostripantennas,compactdual-frequencyanddual-polarized
microstripantennas,compactcircularlypolarizedmicrostripantennas,andcompact
microstripantennaswithenhancedgain,respectively.Chapters7–9aredevotedre-
spectivelytoadvanceddesignsforbroadbandmicrostripantennas,broadbanddual-
frequencyanddual-polarizedmicrostripantennas,andbroadbandanddual-bandcir-
cularlypolarizedmicrostripantennas.
Chapter 2 introduces recent advances in compact microstrip antennas. Based on
recentcompactdesigntechniques,suchasusingashortedpatch,ameanderedpatch,
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
thischapter.Detailsofantennadesignsandexperimentalresultsarepresented.
Chapter3discussescompactbroadbandmicrostripantennadesigns.Designtech-
niquesforachievingbroadbandoperationwithareducedantennasizearedescribed.
Relatedtechniquesincludetheuseofashortedpatchwithathickairsubstrate,stacked
shortedpatches,chip-resistorloading,chip-resistorandchip-capacitorloading,and
slot loading in the radiating patch or ground plane. Chapter 4 presents designs for
compactdual-frequencyanddual-polarizedmicrostripantennas.Recentadvancesin
regular-sizedual-frequencydesignsarefirstdiscussed,andthendesignsforachieving
compact dual-frequency operation with same-polarization and orthogonal polariza-
tion planes are described in detail. Both regular-size and compact dual-frequency
designsarediscussed,whichshouldgivethereaderamorecompleteviewofrecent
developmentsindual-frequencydesign.Advancesincompactdual-polarizeddesign
arealsoreviewed,anddesignexamplesaregiven.
Advancesincompactcircularlypolarized(CP)microstripantennasareconsidered
inChapter5.ExamplesofcompactCPdesigns,includingthoseusingaprobefeed,an
edge-fedmicrostrip-linefeed,oraninset-microstrip-linefeed,arepresented.Designs
forachievinggain-enhancedcompactmicrostripantennasareincludedinChapter6.
Some design examples for active compact microstrip antennas and gain-enhanced
compactcircularlypolarizedmicrostripantennasaregiven.
Chapter 7 is devoted to recent advances in broadband microstrip antennas.
Advancesinbroadbandmicrostripantennaswith,forexample,additionalmicrostrip
resonators,anairorafoamsubstrate,slotloading,orintegratedreactiveloadingare
presentedanddiscussedindetail.Broadbanddesignswithreducedcross-polarization
radiation are presented. Chapter 8 presents broadband dual-frequency and dual-
polarized microstrip antennas. Various design examples are presented, and design
considerationsforachievinghighisolationandlowcross-polarizationforbroadband
dual-polarizedradiationareaddressed.
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◦phaseshiftsarestudied.Inadditiontoobtainingawideaxial-ratio
bandwidth,itisshownhowtoimproveCPqualityintheentireradiationpatternto
achievewide-angleCPcoverage,andrelateddesignsarepresented.Recentadvances
indual-bandCPradiationareincludedinthischapter.
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PREFACE xi
Thisbookisintendedtoorganizenewadvanceddesignsofcompactandbroadband
microstripantennas,mainlythosereportedsince1997.Over100advancedmicrostrip
antennadesignsandtheirdetailedexperimentalresultsareincluded.Itisbelievedthat
thisbookcanbeaveryusefuldesignreferenceoncompactandbroadbandmicrostrip
antennasforantennascientistsandengineers.
KIN-LUWONG
Kaohsiung,Taiwan