COMSOL AC-DC模块

MasteringAC/DCandRFSimulations,MagnusOlsson,Contents,IntroductiontotheRFandAC/DCModulesFormulationsChoosingsolversTipsandtricksBoundarysettingsHandlinghighcontrastGlobalconstraintsForcecomputationsNewtransientsolvertweakingthesettingsHandlinglargescaledifferences,COMSOLProductsforElectromagneticSimulations,COMSOLMultiphysics,AcousticsModule,ChemicalEngineeringModule,StructuralMechanicsModule,EarthScienceModule,HeatTransferModule,MEMSModule,RFModule,CADImportModule,MaterialLibrary,AC/DCModule,VariousmultiphysicscombinationswithelectricfieldsnotavailableinAC/DCandRFmodules(Piezoelectric,Piezoresistive,Electrokinetic,Electroosmotic,etc.),I-Vterms,waveterms,EM,MaxwellsEquations,Maxwell-AmpereslawFaradayslawGausslaw,electricGausslaw,magneticEquationofContinuity,Potentials,MagneticVectorPotential,A,ElectricPotential,V,MagneticScalarPotential,Vm,Formulations,Electrostatics,unknownV:,Quasi-statics,unknownH:,Electriccurrentsquasi-statics,unknownV:,Magnetostatics,nocurrents:,Formulations,Quasi-statics,unknownVandA:,ElectromagneticWaves,unknownA,EorH:,ChoosingSolversforElectromagneticProblems,Solversforvectorfieldproblems,AllEMproblems,Vectorproblems,Mixedvector-scalar(e.g.A-V),Scalarproblems(V,Vm,Az,Hphi,etc.),Inherentgauge,Gaugeenforced,Ungauged,Gaugeexpected,unenforced,Gaugefreedom,SORvector,Vanka,SORgaugeSOR(plain),Nogaugeissues,SOR(plain),Userdecides,Userdecides,Physicsdecides,conductivemediaMagnetostatics-no-currents(Vm)Quasistatics,electriccurrents(V)2Dproblemsareusuallypurelyscalar,except:In-PlaneElectricandInductioncurrents(Ax,Ay;V)TransientIn-PlaneTMwaves(Ax,Ay)TransientIn-PlaneHybridwaves(Ax,Ay;Az),InRFModule,all3Dproblemsarevector,Inherentgaugeorgaugefreedom?,AvectoriseitherAx,Ay,Azin3D,orAx,Ayin2D(in-planeinduction),orAr,Azinaxi-2D(meridionalinduction)Perpendicular/azimuthalinductiongivesscalarequation(Az/Aphi),AC/DC,RF,Whenshouldoneenforcegauge?,Inproblemswithinherentgauge:WheninherentgaugedegeneratesinsomesubdomainsAvoidthisbyusingnon-zeroconductivityinallsubdomainsInproblemswithgaugefreedom:Whenunabletoadjustiterativesolversrecommendedforungaugedformulations,Iterativesolvers,inherentgauge,Category2:Vectorformulations,inherentgauge(nogaugefixingequation)GMRES+GMG(precond.)+SOR/SORUVector(smoothers)+directsolverThisisthestandardsituationforRFModuleapplicationsGMRES+SSORVector(precond.)GMG+SOR/SORUVector(smoothers)Tryplayingwithallthreecombinationsinmodel“EddyCurrents3D”(ModelLibraryAC/DCGeneralIndustrialApplications)Reminder:directsolversPARDISO,SPOOLES,UMFPACKwillworkhere(givenenoughmemory),Iterativesolvers,enforcedgauge,Category3:Enforcedgauge(extraequation)GMRES+GMG(precond.)+Vanka/Vanka(smoothers)+directsolverUsewithRFapplicationswhenunabletoavoidgaugingGMG+Vanka/Vanka(smoothers)+directsolverExample:AC/DCPowerInductorGMRES+Vanka(precond.)Example:AC/DCBondWirestoChip(hands-onexercisetoday)Reminder:directsolversPARDISO,SPOOLES,UMFPACKwillworkhere(givenenoughmemory),Iterativesolvers,ungauged,Category4:UngaugedformulationsFGMRES+GMG(precond.)+SOR/SORU(smoothers)+GMRES(coarse)+SSOR(precond.)Recommendedforalltypesofungaugedformulations(staticA,staticA-V,time-harmonicA-V)FGMRES+GMG(precond.)+SOR/SORUgauge(smoothers)+GMRES(coarse)+SSORgauge(precond.)RecommendedforstaticAandA-VformulationsFGMRES+GMRES(precond.)+SSOR(precond.)Recommendedfortime-harmonicA-VFGMRES+SSORgauge(precond.)RecommendedforstaticAformulations,TipsandTricksforElectromagneticProblems,1:Boundaryconditions,Useboundaryconditionstoreplacesubdomainsandtodrivemodels,EdgeandPointconditions,LineCurrent(3D):Specifyaknowntime-harmoniccurrentthroughaline(awireofzeroradius)PointCurrent(2D):Specifyaknowncurrentperpendiculartothemodelingplane,I0sin(t),I0sin(t),Visualizingedgetangentdirections,PerfectElectricConductor(PEC)/MagneticInsulation,PECE=0,E-field,TheElectricFieldB.C.fixestheE-fieldattheboundary,inatime-harmonicsense.TheElectricFieldB.C.,asopposedtothePECB.C.,israrelyused.,Modelshighlyconductivemedia,withnolosses.Zero-impedancecondition.,ImpedanceBoundaryCondition,ImpedanceB.C.Specify,r,r,n,E-field,Modelshighlyconductivemedia,withlosses.,PerfectMagneticConductor(PMC)/ElectricInsulation,PMCnH=0,E-field,TheMagneticFieldB.C.fixestheH-fieldattheboundary,inatime-harmonicsense.TheMagneticFieldB.C.,asopposedtothePMCB.C.,israrelyused.,Symmetryboundary.High-impedancecondition.,SurfaceCurrent,SurfaceCurrentJ=Js,E-field,Modelsasurfacewithaknowncurrentflowingtangentially.,Example:Drivingsurfacecurrents,ScatteringBoundaryCondition(SBC),Incidentplanewave,ScatteredWave,AnSBCallowsanincidentplanewavetopassthroughfromanydirectionAscatteredwaveofaknownwave-typewillpassthroughanSBC,ComputationalDomain,ScatteringBoundaryCondition,ScatteredField,Setthetypeofthescatteredwavehere.Usually,thisisknownonlyapproximately.Forcylindricalandsphericalscatteredwaves,alsosetacenterpointandaxisThisonlyaffectsthescatteredfield,anddoesnotaffecttheincidentfield.,ScatteringBoundaryCondition,IncidentField,Magnitude,(andphase)Directionoftheincidentplanewave,TheSBCisperfectlyinvisibleonlytoscatteredwavesthatareknownprecisely,IncidentWave,ScatteredWave,MatchedBoundaryCondition(MBC),Ifthepropagationconstantofthefieldattheboundaryisknown,thenusetheMBC.Canalsoapplyanincidentfield,iftheshapeofthefieldisknown.Thisneednotbeaplanewave.,Ifyouknowtheexactwavevector,theMatchedBoundaryistransparent,ScatteringBoundaryCondition,MatchedBoundaryCondition,AddingwavesatanangletoanMBCorSBC,Mustincludespatialandphasevariation,x,y,PMLvs.ScatteringBoundaryCondition,ScatteringBoundaryCondition,PML,RadiatingCylinder,PortBoundaryCondition,ThisisthesameasanMBCwithtwoextensions:1)S-parameters2)Analyticandnumericports,PortBoundaryCondition,Applyananalyticornumericsolutionfortheshapeofthefieldsontheboundary.Seewaveguideadaptermodelinmodellibraryforatutorial,LumpedPorts,PEC,PEC,LumpedPort,d,Lumpedportsareappropriatewhenthedimensionsaremuchsmallerthanthewavelengthandthetrueincidentfieldisunknown(TEMapproximation),Example:DipoleandYagiantennasin3D,Default3DView,XYView,PeriodicBoundaryCondition,Edst=Esrc,Edst=-Esrc,Continuity,Anti-periodcity,FloquetPeriodicBoundaryCondition,example,FloquetPeriodicBoundaryCondition,example,FloquetPeriodicBoundaryCondition,example,MustenterFloquetperiodicsourceterm,2:Handlinghighcontrast,3:Globalconstraints,Globalconstraint:Example:FindinducedvoltageinaburiedpipelineunderahighvoltagelineBonus:MeshinginfiniteelementsandPMLsAdvancedexample:RFInductorinaxisymmetry,4:Forcecomputations,Maxwellstresstensormethod-wasNewtonright?Bonusfeature:adaptiononlinearfunctionalUsingvirtualwork,5:Tweakingofnewtimesolverinthenonlinearsettings(MO),6:Handlinglargescaledifferences,EmbeddedthinwiresLeakyshielding,Leakyshieldingacommonproblem,Electromagneticshieldingtypicallyemploysthin