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首页 Fundamentals of Electromagnetics with Matlab - …

Fundamentals of Electromagnetics with Matlab - Lonngren & Savov.pdf

Fundamentals of Electromagnetic…

上传者: 阿莫斯下着雨 2012-07-05 评分 0 0 0 0 0 0 暂无简介 简介 举报

简介:本文档为《Fundamentals of Electromagnetics with Matlab - Lonngren & Savovpdf》,可适用于人文社科领域,主题内容包含vContentsPrefaceixChapterMATLABandVectorsMATLABandaReviewofVectorsCoordina符等。

vContentsPrefaceixChapterMATLABandVectorsMATLABandaReviewofVectorsCoordinateSystemsIntegralRelationsforVectorsDifferentialRelationsforVectorsPhasorsConclusionProblemsChapterStaticElectricandMagneticFieldsCoulomb’sLawElectricFieldSuperpositionPrinciplesGauss’sLawPotentialEnergyandElectricPotentialNumericalIntegrationDielectricMaterialsCapacitanceElectricalCurrentsFundamentalsofMagneticFieldsMagneticVectorPotentialandtheBiotSavartLawMagneticForcesMagneticMaterialsMagneticCircuitsInductanceBoundaryConditionsConclusionProblemsLonngrenSavovTOCfmPagevWednesday,January,:PMviContentsChapterBoundaryValueProblemsUsingMATLABPoisson’sandLaplace’sEquationsAnalyticalSolutioninOneDimensionDirectIntegrationMethodNumericalSolutionofaOneDimensionalEquationFiniteDifferenceMethodAnalyticalSolutionofaTwoDimensionalEquationFourierSeriesExpansionFiniteDifferenceMethodUsingMATLABFiniteElementMethodUsingMATLABMethodofMomentsUsingMATLABConclusionProblemsChapterTimeVaryingElectromagneticFieldsFaraday’sLawofInductionEquationofContinuityDisplacementCurrentMaxwell’sEquationsPoynting’sTheoremTimeHarmonicElectromagneticFieldsConclusionProblemsChapterElectromagneticWavePropagationWaveEquationOneDimensionalWaveEquationTimeHarmonicPlaneWavesPlaneWavePropagationinaDielectricMediumReflectionandTransmissionofanElectromagneticWaveWaveguidePropagationwithDispersionConclusionProblemsChapterTransmissionLinesEquivalentElectricalCircuitsTransmissionLineEquationsSinusoidalWavesTerminationsImpedanceontheTransmissionLineandMatchingSmithChartLonngrenSavovTOCfmPageviWednesday,January,:PMviiTransientEffectsandtheBounceDiagramPulsePropagationLossyTransmissionLinesDispersionandGroupVelocityConclusionProblemsChapterRadiationofElectromagneticWavesRadiationFundamentalsShortElectricDipoleAntennaLongDipoleAntennaAntennaParametersMagneticDipoleAntennaApertureAntennas,DiffractionofWavesAntennaArraysConclusionProblemsAppendixAMathematicalFormulasAVectorIdentitiesAVectorOperationsintheThreeCoordinateSystemsASummaryoftheTransformationsBetweenCoordinateSystemsAIntegralRelationsAppendixBMathematicalFoundationoftheFiniteElementMethodBMinimumEnergyConditionBLinearInterpolationCoefficientsBSmatrixElementsBDecoupledandCoupledNodePotentialsBTheMatrixEquationfortheUnknownPotentialsAppendixCMaterialParametersAppendixDTransmissionLineParametersofTwoParallelWiresAppendixEPlasmaEvolutionAdjacenttoaMetallicSurfaceAppendixFReferencesAppendixGAnswersIndexLonngrenSavovTOCfmPageviiWednesday,January,:PMLonngrenSavovTOCfmPageviiiWednesday,January,:PMivPrefaceElectromagneticFieldTheoryisoneofthefundamentalcoursesthatanelectricalandcomputerengineeringstudentisrequiredtotakeinordertogainaphysicalunderstandingofthefoundationsandtheheritageofthefieldthatwilloccupyhisorherprofessionallifefortheseveraldecadesfollowinggraduationTheacquiringofanappreciationforthelawsofnaturethatgovernandlimitthespeedofthesmallestcomputerchipcontinuetobecrucialasthisspeedapproachestheultimatelimitWiththemanychangesthatareoccurringinundergraduatecurriculumsduetotherapiddevelopmentofnewtechnologiesandhenceadditionalcourses,itiscommontofindthatonlyonecourseinelectromagnetictheoryisnowrequiredforstudentsHowever,mostofthestudentsare“computersavvy”andhavebeenintroducedtoandhaveusedMATLABintheirpreviouscoursesandaremotivatedbyitsabilitytocreatepicturesonacomputerscreenthatcanhelpillustratecomplicatedphysicalphenomenaOurApproachTheunderlyingphilosophyofthisonesemesterundergraduatetextistocombinethestudent’scomputerMATLABabilitythathasbeengainedinearliercourseswithanintroductiontoelectromagnetictheoryinacoherentfashioninordertostimulatethephysicalunderstandingofthisdifficulttopicWheretwotermsofElectromagneticTheorywereoncerequired,thechallengeofsqueezingstudyintoonetermcanatleastbepartiallymetwiththeuseofMATLABtodiminishthedrudgeryofnumericalcomputationswhileenhancingunderstandingofconceptsTherefore,inthistextnumerousexamplesaresolvedusingMATLABalongwiththecreationofseveralfiguresthroughoutthetext,andallofthe“m”filesaremadeavailableforthereadertoexamineandtomodifyWethereforebelievethatitispossibletotakethisseeminglyabstractmaterialandmakeitunderstandableandinterestingtothestudentThisbeliefhasbeenconfirmedbyusingthematerialinclassesforsixyearsandcontinuallyusingstudentfeedbacktoimproveitchdprefacefmPageivWednesday,December,:AMvPrefaceOrganizationoftheTextWereviewessentialfeaturesofMATLABimmediatelyinChapterinordertosatisfythenovice’sinitialtrepidationsandincorporateitsMATLAB’scapabilitiesthroughouttheentiretextAfteraninitialreviewinChapterofMATLAB,vectorcalculus,andphasors,wefollowinthefootstepsofthegiantswhohaveprecededusinandsummarizethefundamentalsofstaticelectromagneticfields,includingseveralexamplesthatthereadermayhaveencounteredpreviouslyWediscussanalyticalandMATLABtechniquesinordertoillustratethespatialbehaviorofastaticfieldinafiniteboundaryinChapterThemajorityofthetextisdirectedtowardthepresentationoftimevaryingelectromagneticfieldsandMaxwell’sequationsinChapterFromtheseequationswederiveawaveequationthatcanbemosteasilyunderstoodusingadiverseselectionofexamplesfromotherdisciplinesAstudyofplaneelectromagneticwavesdirectlyfollowsthisreviewofwavesinChapterInChapterthesubjectoftransmissionlinesisemphasized,owingtoitsimportanceinmoderntechnologyThisincludesMATLABprogramsforthecreationofaSmithchartanditsapplicationFinally,inChapterthesubjectofradiationofelectromagneticwavesisexplained,firstfromaverysimplephysicalinterpretation,andthensummarizingmanyoftheimportantparametersassociatedwithantennasAnticipatingthestudent’sfurtherstudyofmoderntopicsinelectricalengineering,wehavetriedtopresentasomewhatbroaderlookinnumericalmethodsthanmostintroductoryelectromagneticstextsTheFiniteElementMethod,MethodofMoments,andFiniteTimeDifferenceareallexamplesofthiseffortWithMATLAB,webelievemoststudentscanhandlethismaterialwellandwillbebetterpreparedfortheirapplicationlaterAidstoLearningTheAppendicesandpagelayoutaredesignedtoenhancethereader’sunderstandingandappreciationofelectromagnetictheoryasitappliestotheirstudy•Exampleshavebeenclearlysetoffromthetextwithrulelines•EachtimeMATLABisemployed,whetherinexamplesorchapterproblems,theMATLABiconisusedtosignifyitsuse•TheanswerstoallproblemshavebeenincludedinAppendixGsothatstudentscancheckalloftheirwork,notjustsomeInstructorsareprovidedwithcompleteworkedoutsolutionsinhardcopyandMATLABfiles,touseattheirdiscretionchdprefacefmPagevWednesday,December,:AMvi•Themostimportantequationsoccurringinthetexthavebeenboxedsothattheymightbequicklyidentifiedassuchandcommittedtomemory•ImportantmathematicalformulaehavebeenconsolidatedandplacedtogetherinAppendixA•SeveralinterestingextensionsoftextmaterialareofferedinAppendixB(MathematicalFoundationoftheFiniteElementMethod)andAppendixE(PlasmaEvolutionAdjacenttoaMetallicSurface)•MaterialparametersarelistedinAppendixC•AfairlyextensiveanduptodatelistofreferencesforbothelectromagneticsandMATLABisprovidedinAppendixFAidstoTeachingForinstructors,weareworkingcloselywithSciTechPublishingtosupplyourteachingcolleagueswithampleresourcesandtoaddtothemcontinuously,eventoinvitecontributionsfromthemandtheirstudentsAninitialCDROMofferscompletesolutionstoproblemsinhardcopy(PDFandWord)aswellasMATLABmfilesThecodeforallMATLABgeneratedfiguresismadeavailableontheCD,aswellasonthewebforstudentsAllotherfiguresusedinthetextareprovidedasEPSgraphicfilesaswellasinaPowerPointfileAmodestnumberofMATLABanimationfileshavebeencollected,withthehopethattheauthorsandouradoptinginstructorswilladdtothemCheckinfrequentlyatourwebsitetoseewhathasbeenadded:wwwscitechpubcomlonngrenhtmAcknowledgmentsTheconstructionofaneffectivetextbook,withitsattendantresourcematerials,isateameffortakintoanengineeringmarvelWearefortunatetoworkwithapublisherthatbelievesinoureffortandmaintainsanopenandconstantdialogInparticular,oureditorandSciTechPublishingfounderDudleyKayhasextendedhisconsiderableyearsofexperienceincommercialpublishingandatIEEEPresstodispenseadviceandencouragement,makingthefinishedbookevenbetterthanwehadfirstenvisagedRobertKern,MelissaParker,andtheteamatTIPSTechnicalPublishing,Incprovidedanoutstandingpagedesignandworkedtirelesslyonthehundredsofartandequationfilestobringtextandgraphicstogetherintoacoherent,attractivewholeOurearlyfigureswerebroughttoprofessionalpolishbyMichaelGeorgiev,workingunderthedemandingguidanceofProfSavovThestrikingtimedelaychdprefacefmPageviWednesday,December,:AMviiPrefacephotographofarocketprobeintotheauroraborealiswasadaptedbyBrentBeckleyintothebrilliantcoverdesignOfcourse,despitethemostrigorousofeffortsandcapabilitiesofourfineteam,anyerrorsthatoccurareoursWestronglyencourageyourfeedbackonanyaspectofthebookthatcouldbeimprovedandpledgetocorrectanyerrorsreportedtousorthepublisherTheauthorshaveprofitedfromextendeddiscussionswithseveralpeoplewhohaveinfluencedtheirthinkingconcerningthepresentationofthismaterialThisincludestheirformerteachers,theirpastandpresentelectromagneticscolleagues,andthemanystudentswhohaveaskedstimulatingquestionsinandoutsideofclassoverthelastthreedecadesInparticular,ProfessorsErWeiBai,AdrianKorpel,andJonKuhlprovidedvaluableassistanceatcrucialtimesFinally,theauthorsthanktheirwivesVickiandRossifortheirencouragementandunderstandingduringthisendeavor,andthisbookisdedicatedtothemKarlELonngrenUniversityofIowaLonngrenenguiowaeduSavaVSavovTechnicalUniversityatVarnaVarna,BulgariasvsavovmsieeebgchdprefacefmPageviiWednesday,December,:AMMATLABandareviewofvectorsMATLABandvectorsInthischapter,weintroduceandsummarizeseveralpropertiesofthesoftwareprogramentitledMATLABThetopicsinthissummaryhavebeenselectedbasedontheirlaterapplicationinourstudyofelectromagneticsYouhaveprobablyencounteredMATLABinothercoursessincethesoftwareiswidelyusedintheeducationalcommunityInaddition,MATLABisatoolthatwillpermityoutoeasilyobtainpicturesofvariouselectromagneticphenomenathatwewillencounterinourjourneythroughthisbookInaddition,vectorswhicharecrucialindescribingelectromagneticphenomenacanbeeasilymanipulatedusingMATLABSeveralofthefiguresinthistexthavebeencreatedusingMATLABBecauseofsimplicity,wewillemphasizeCartesiancoordinatesinthisreviewThevectoroperationsinothercoordinatesystemsareincludedinAppendixOurmotivationinemployingvectorsisthatelectromagneticfieldsarevectorquantitiesandtheirusewillpermitustouseafairlycompactnotationtorepresentsetsofpartialdifferentialequationsThisreviewwillincludeaderivationofthevectordifferentialoperationsofthegradient,thedivergenceandthecurlThetransformationofavectorfromonecoordinatesystemtoanotherwillbediscussedAdditionalsymmetryfoundinaparticularprobleminonecoordinatesystemoveranotheronemaysuggestsuchatransformationThereaderwhofeelscomfortablewithvectorterminologycaneasilyskipthisportionofthechapterandpassonwithnolossofcontinuityJustrememberthatinthistext,boldfacetypewillbeusedtodefineavectorAandthesymboluAwillbeMATLABandareviewofvectorsusedtoindicatetheunitvectorcorrespondingtothisvectorThischapterconcludeswithafewbriefcommentsonphasorsMATLABandareviewofvectorsMATLABandareviewofvectorsMATLABisasoftwareprogramthatiswidelyavailablefordigitalcomputersatalargenumberofuniversitiesandonalargevarietyofmachinesAswillbenotedinthistext,wewillmakeextensiveuseofitThetwoandthreedimensionalplottingcapabilitieswillbeexploitedthroughoutthistextsinceapictureoragraphcanusuallyaidinthephysicalinterpretationofanequationHerein,wewillbrieflypresentanintroductionofseveralgermanefeaturesofthisprogramthatwillbeusefulforelectromagnetictheoryVariousfunctionssuchastrigfunctionsappearinaMATLABlibrarythatcanbeeasilycalledandusedTheusercancustomizeandaddtothislistbywritingaprogramina"m"(dotm)fileSeveralMATLABfigureswillbeincludedthroughoutthistextInaddition,thefilesthathavebeenusedtocreatethefiguresinthetextareavailableatthefollowingwebsite:http:wwwscitechpubcomTheseprogramswillbecharacterizedwiththenames:“example”and“figure”toindicatethethirdexampleandthethirdfigureinchapterTheexampleandfigurecaptionsareidentifiedinthebookwiththesuperscriptnotationMATLABMatrixoperationswillnotbeexaminedsincetheirapplicationwillreceiveminimalattentioninthistextWeassumethatthereaderisabletocallMATLABandhavethefamiliarMATLABprompt">>"appearonthescreenTypingthewords,"helptopic"afterthepromptbringsonscreenhelptotheuserForexample,wetypewithoutthefollowingcommandaftertheprompt,presstheenterkey,andnotethefollowingstatementsthatappearonthescreenMATLABandareviewofvectors>>x=x=()>>ThecomputerhasassignedavalueforthevariablexthatitwillrememberuntilitischangedoruntilweexittheprogramItisnowreadyforthenextinputLetuschooseavaluey=butdesirethecomputertonotprintbackthisnumberimmediatelyThisisaccomplishedwithasemicolon“”>>y=>>()ThismaynotseemimportanttothestageHowever,asimplestatementinaprogramcouldleadtoalargewasteof“computerscreen”orcomputerpaperasthenumbersarespewedforthMathematicaloperationswiththesetwonumbersfollowandwewriteamathematicaloperationatthepromptInthetablegivenbelow,thefollowingthreelineswillappearafterwepushthereturnkeyAdditionSubtractionMultiplicationDivision>>z=xy>>z=x–y>>z=x*y>>z=xyz=z=Z=z=>>>>>>>>NotethefourplaceaccuracyinthelastcolumnTheaccuracycanbecontrolledbytheuserMATLABandareviewofvectorsWiththesemicolonnotation,itispossibletowriteanyofthecommandsinonelineForexample,theadditionprogramcanalsobewritteninonelineas>>x=y=z=xy()Inordertoobtainedthesolutionusingthisoperation,youjusthavetotype“z”attheMATLABpromptandcomputerwillrespond>>z()>>ThesemicolonwillbeveryusefulinalengthycalculationifwedonotwishtodisplayintermediateresultsAnotherusefultooltorememberisthesymbol""sinceanythingtypedonthelineafteritwillreceivenoattentionbythecomputerItisaconvenientwaytoaddcommentstoaprogramortoanoperationInelectromagnetics,you'llfrequentlyencounterfieldsthathavebothamagnitudeandadirectionassociatedwiththemExamplesofphysicaleffectsfromotherdisciplinesthatrequireavectornotationincludeforce,acceleration,andvelocityAcartravelingwithavelocityvfromalocationAtoadifferentlocationBimpliesthatthecarhasacertainspeedv=|v|inaprescribeddirectionInthiscase,thespeedisthemagnitudeofthevelocityThevectorshouldbecontrastedwithascalar,aquantitythatpossessesonlyamagnitudeandnodirectionEnergy,weightandspeedareexamplesofscalarquantitiesOurcarcantravelwithaspeedvinanydirectionbutwillpassusbywithavelocityvinadefinitedirectionMATLABandareviewofvectorsTheconvenienceofemployingvectornotationallowsusvisualizeproblemswithorwithoutthespecificationofacoordinatesystemAfterchoosingthecoordinatesystemthatwillmostaccuratelydescribethefield,thefieldisthenspecifiedwiththecomponentsdeterminedwithregardtothiscoordinatesystemCoordinatesystemsthatwewillencounterlaterareCartesian,cylindrical,andsphericalThederivationsofvectoroperationswillbeperformedinCartesiancoordinateswiththeequivalentresultsjuststatedintheothersystemsTherearealargenumberof“orthogonal”coordinatesystemsandthereisageneralizedorthogonalcoordinatesystemTheterm“orthogonal”impliesthateverypointinaparticularcoordinatesystemcanbedefinedastheintersectionofthreeorthogonalsurfacesinthatcoordinatesystemThiswillbefurtherexaminedlaterAvectorcanbespecifiedinMATLABbystatingitsthreecomponentsWewilluseacapitallettertoidentifyavectorinusingMATLABnotationLowercaseletterswillbereservedforscalarquantitiesThisisnotrequiredbutitdoesaddclaritytotheworkTheunitvectorisdefinedasavectorwhosemagnitudeisequaltoanditisdirectedinthesamedirectionasthevectorForexampleinaCartesiancoordinatesystem,thevectorA=AxuxAyuyAzuzwhereAxisthemagnitudeofthexcomponentofthevectorAanduxisaunitvectordirectedalongthexaxisiswrittenas>>A=

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