development of four novel uwb antennas assisted by fdtd method

183 Pages·2011·9.11 MB·English

DEVELOPMENT OF FOUR NOVEL UWB ANTENNAS
ASSISTED BY FDTD METHOD
DISSERTATION
Presented in Partial Fulfillment of the Requirements for
the Degree Doctor of Philosophy in the
Graduate School of The Ohio State University
By
Kwan-Ho Lee, B.S.E.E.,M.S.E.E.
* * * * *
The Ohio State University
2004
Dissertation Committee: Approved by
RobertLee, Adviser
Chi-ChihChen
Adviser
Fernando L.Teixeira
Graduateprogramin
ElectricalEngineering
(cid:0)c Copyrightby
Kwan-HoLee
2004
ABSTRACT
Due to high demand for wide bandwidth applications, UWB antennas have received
significant attention in many commercial and military application areas. They can pro-
vide very wide bandwidth information with a single antenna configuration. However, de-
signing UWB antennas have very strict requirement such as broadband matching, broad
beamwidth, and good efficiency throughout the operational frequency band which is gen-
erallydifficulttoobtain.
In this work, the finite different time domain (FDTD) method was selected for the de-
sign andoptimization ofUWB antennas in manydifferent applicationareas. They include
ground penetrating radar (GPR), anechoic chamber feed antenna, near field probe antenna
andtaperedchamberfeed. AlltheseantennasrequireUWBoperation,duallinearpolariza-
tion,andbroadbeamwidth. Foreachapplicationarea,theyhavetheirowndetailoperation
requirements. With the help of the FDTD code and through understanding, the antennas
aredeeplystudiedandanalyzedforthefinaldesign. Thisprocesssavestimeandcostcom-
pared to the repeated prototyping. For the verification of the numerical result, prototype
antennasarebuilt,measuredandcomparedtoitsnumericalmodelresult. Themeasurement
andthesimulationsagreedueto therealistic modelingofthegeometry.
ii
Formyparents,mywifeChoon-Seon,SonLiam,DaughterKateandthe Truth
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ACKNOWLEDGMENTS
I would like to give my deep gratitude to Professor Robert Lee, my academic advisor,
forhispatienceandallofthetechnicaladvisethroughoutmygraduateworkandresearchat
theElectroScienceLaboratory,theOhioStateUniversity. AndSpecialappreciationshould
beextendedtoDr. Chi-ChihChen,mysupervisor,whocarefullyreviewedthedissertation
andgavemesuggestionsandimprovementsinthiswork. Hisencouragementandtechnical
advise througout this work give me invaluable experience in both of the theoretical and
techincal aspects. I also would like to appreciate Professor Fernando L. Teixeira for his
reviewofmydissertationandtechnicaldiscussions.
I’d liketo thank my colleagues,Panuwat Janpugdeeand MarinosVouvakis for sharing
valuablediscussionstosolvesomeoftheapplicationproblems,andC.J.Moncriefforhelp-
ingtosetupthemeasurementconfigurationintheanechoicchamberattheElectroScience
Laboratory.
Finally,I would liketo express my specialappreciationto my lovingwife Choon-seon
Oh forherendlesspatienceandsupportduringmy academicyears.
iv
VITA
August11,1970 ............................ Born-Sang-Joo,Korea
March,1997 ................................B.S. Radio Science and Engineering,
KwangwoonUniversity,Seoul,Korea
December,1996-July,1997 ................. Researcher, SamSung Telecommunica-
tionResearchCenter,Seoul,Korea
September,1997-December,1999 ........... GraduateResearchAssociate,
TheElectroScienceLaboratory,
TheOhioStateUniversity
December,1999 ............................ M.S. Electrical and Computer Engineer-
ing,TheOhioStateUniversity
December,1999-Present ....................GraduateResearchAssociate,
TheElectroScienceLaboratoty,
TheOhioStateUniversity
PUBLICATIONS
REFEREEDJOURNALARTICLES
1. K. H. Lee, C. C. Chen, F. Teixeira, and R. Lee, “Modeling and Optimizing of Ge-
ometrically Complex UWB antenna using FDTD”, IEEE Trans. on Antennas and
Prop.,Vol 52,pp 1893-1991,August2004.
FIELDS OF STUDY
MajorField: ElectricalEngineering
v
Studies in:
ComputationalElectromagnetics Prof.RobertLee
Prof.EdwardNewman
TheoreticalElectromagnetics Prof.RobertoRojas
Prof.PrabhakarPathak
Mathematics Prof.Ulich Gerlach
ComputerScience Prof.BruceW.Weide
Prof.FurrukhKhan
Circuits Prof.PatrickRoblin
Prof.MohammedIsmail
vi
TABLE OF CONTENTS
Page
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Dedication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
Vita . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
ListofTables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x
ListofFigures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Chapters:
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2. Finite DiffernceTimeDomainMethodin UWBantennaDesigns . . . . . . . . 7
2.1 ThreeDimensionalMaxwell’sEquationsinRectangularCoordinateSys-
tem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 Modeling ofResistivecardloadings . . . . . . . . . . . . . . . . . . . . 9
2.2.1 Resistivecard loadingin threedimensionalFDTD . . . . . . . . 10
2.3 CoaxialCableModeling andTimeDomainPulseExcitation . . . . . . . 14
2.3.1 ModelingofCoaxialCables . . . . . . . . . . . . . . . . . . . . 15
2.4 Perfectelectricconductor(PEC)PlateModeling . . . . . . . . . . . . . 17
2.5 PerfectMatchedLayer(PML)ModelingforInhomogeneousMedia . . . 17
2.6 PartitionScheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.7 Summary ofthe Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . 21
vii
3. DesignofHorn-fedBowtie(HFB)AntennaforGPR applications . . . . . . . . 23
3.1 BasicDual-polarizedHFB AntennaDesign . . . . . . . . . . . . . . . . 24
3.1.1 ResistiveTaper Section . . . . . . . . . . . . . . . . . . . . . . 24
3.1.2 Feed Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.2 FDTDModelDescription . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.2.1 HeterogeneousFDTD DomainPartition . . . . . . . . . . . . . 27
3.2.2 Feed CableModeling . . . . . . . . . . . . . . . . . . . . . . . 29
3.2.3 ResistiveCard Modeling . . . . . . . . . . . . . . . . . . . . . . 31
3.3 CharacteristicsofDual-polarizedHFBAntennaDesign . . . . . . . . . . 32
3.3.1 S &S andInput Impedance . . . . . . . . . . . . . . . . . . 32
11 21
3.3.2 Groundeffect . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.3.3 R-cardperformanceinvestigation . . . . . . . . . . . . . . . . . 35
3.3.4 AntennaRinging . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.3.5 RadiatedFieldDistribution& Polarization . . . . . . . . . . . . 40
3.4 Conclusionofthe Chapter . . . . . . . . . . . . . . . . . . . . . . . . . 42
3.4.1 ParametersummaryofHFB geometry . . . . . . . . . . . . . . 42
4. Design of Dielectric Rod Probe (DRP) Antenna for Near field measurement
range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
4.1 AUWBDRP DesignPrinciples . . . . . . . . . . . . . . . . . . . . . . 47
4.2 UWB-DRPGeometry . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
4.2.1 Feed antennasection . . . . . . . . . . . . . . . . . . . . . . . . 48
4.2.2 Waveguidesection . . . . . . . . . . . . . . . . . . . . . . . . . 48
4.2.3 Radiationsection . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4.3 Numericalresultforimprovedradiationsection . . . . . . . . . . . . . . 50
4.3.1 Numericalmodeling . . . . . . . . . . . . . . . . . . . . . . . . 50
4.3.2 Nearfield distributions . . . . . . . . . . . . . . . . . . . . . . . 52
4.3.3 Performancecomparisonfordifferenttipprofiles . . . . . . . . . 54
4.4 MeasuredUWB-DRPCharacteristics . . . . . . . . . . . . . . . . . . . 60
4.4.1 Farfieldradiationpatterns . . . . . . . . . . . . . . . . . . . . . 60
4.5 Conclusionofthe Chapter . . . . . . . . . . . . . . . . . . . . . . . . . 72
5. DesignofDielectricHornAntenna(DHA)forAnechoicChamberfeed . . . . 74
5.1 DHADesignConcept . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
5.2 NumericalAnalysisandFurtherOptimization . . . . . . . . . . . . . . . 80
5.2.1 Specificationofimproved110 -DHAc . . . . . . . . . . . . . . 108
(cid:0)
5.3 MeasurementResult ofImproved110 -DHAc . . . . . . . . . . . . . . 111
(cid:0)
5.3.1 Newprototypeantennaconstruction . . . . . . . . . . . . . . . 111
viii
5.3.2 VSWR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
5.3.3 Radiationpatterns . . . . . . . . . . . . . . . . . . . . . . . . . 113
5.3.4 Antennagains . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
5.4 Conclusionofthe Chapter . . . . . . . . . . . . . . . . . . . . . . . . . 116
6. DesignofUWB NovelTaperedChamberFeed . . . . . . . . . . . . . . . . . 117
6.1 BasicTapered ChamberOperationPrinciple. . . . . . . . . . . . . . . . 119
6.2 NumericalModelingofTaperedChamberFeed Antenna . . . . . . . . . 121
6.2.1 Modelingoffeed section . . . . . . . . . . . . . . . . . . . . . 121
6.2.2 Modelingofmicrowaveabsorber . . . . . . . . . . . . . . . . . 123
6.2.3 Modelingofwave-launchingarm . . . . . . . . . . . . . . . . . 123
6.3 NumericalSimulationandMeasurementResult . . . . . . . . . . . . . . 124
6.3.1 Launchedfielddistributions . . . . . . . . . . . . . . . . . . . . 124
6.3.2 Bandwidthofthe LaunchedField . . . . . . . . . . . . . . . . . 131
6.3.3 Measurementresult . . . . . . . . . . . . . . . . . . . . . . . . 133
6.3.4 Specificationoftaperedchamberfeedsection andfeed antenna . 144
6.3.5 Proposed improved UWB dual-polarization wave - launching
Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
6.4 Conclusionofthe Chapter . . . . . . . . . . . . . . . . . . . . . . . . . 151
7. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
7.1 FuturestudyofUWBAntennasDesign . . . . . . . . . . . . . . . . . . 155
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
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