PCB电磁干扰算法

RadiationfromEdgeEffectsRadiationfromEdgeEffectsRadiationfromEdgeEffectsRadiationfromEdgeEffectsRadiationfromEdgeEffectsRadiationfromEdgeEffectsRadiationfromEdgeEffectsRadiationfromEdgeEffectsinPrintedCircuitBoards(PCBs)inPrintedCircuitBoards(PCBs)inPrintedCircuitBoards(PCBs)inPrintedCircuitBoards(PCBs)inPrintedCircuitBoards(PCBs)inPrintedCircuitBoards(PCBs)inPrintedCircuitBoards(PCBs)inPrintedCircuitBoards(PCBs)Dr.ZoricaPantic-TannerDirector,SchoolofEngineeringDirector,[e-mail],[e-mail]MotivationProblemdefinitionProblemsetupPhysicsofPCBpropagationmodesPhysicsofPCBedgeeffectsMinimizingradiationfromPCBedgesRadiationfromEdgeEffectsRadiationfromEdgeEffectsRadiationfromEdgeEffectsRadiationfromEdgeEffectsRadiationfromEdgeEffectsRadiationfromEdgeEffectsRadiationfromEdgeEffectsRadiationfromEdgeEffectsinPrintedCircuitBoards(PCBs)inPrintedCircuitBoards(PCBs)inPrintedCircuitBoards(PCBs)inPrintedCircuitBoards(PCBs)inPrintedCircuitBoards(PCBs)inPrintedCircuitBoards(PCBs)inPrintedCircuitBoards(PCBs)inPrintedCircuitBoards(PCBs)MotivationMotivationMotivationMotivationMotivationMotivationMotivationMotivationAscompetitiveforcesdriveproductcostsdown,itbecomesincreasinglyimportanttoincorporategoodEMCdesignpracticesintotheproduct-especiallyonesthatprovidesuperiorsuppressionatminimumcost.BecausePCBlayoutpatterns(howtracesandground/powerplanesarestackedandrouted)donotaddtoproductioncosts,thereisatremendousinterestinoptimizingthesestructurestoprovidemaximumEMCsuppression.ThematerialpresentedtonighthighlightssomeoftheongoingresearchinthisareathattheSFSUCenterforAppliedElectromagneticsiscurrentlyworkingoninconjunctionwithitsIndustryPartnershipProgram.MotivationMotivationMotivationMotivationMotivationMotivationMotivationMotivationIEEEEMCSocietyComputationalElectromagneticsTC-9identifiededgeemissionsasasignificantEMCriskphenomenon,andincludeditasoneofitsfourchallengingEMCmodelingproblems.Findtheedgeemissionsfromthefollowingstructure…..MotivationMotivationMotivationMotivationMotivationMotivationMotivationMotivationSolution(fromamodelingperspective)–Findabigfastcomputerwithenoughmemorytoholdtheentiremodel.–Takealongcoffeebreak….–ResultstobepresentedattheIEEE2000EMCSymposiumSolution(fromamodelingperspective–Findabigfastcomputerwithenoughmemorytoholdtheentiremodel.–Takealongcoffeebreak….Modelingentirestructureonacomputerdoesnotprovideinsightintowhat’sgoingon.Ifwe“unbundle”theproblemintoitscomponentpieces,lookatthephysicsofeachcomponent,wecanusetheinsightgainedfromthisprocesstofigureoutwhatisgoingon.–Howbadisit?–Doesthe20Hrule(pullingbackpowerplanes)work?–Doesfencing(groundingviasaroundperipheryofPCB)work?–Arethesetheonlytwotechniquesatourdisposal?MotivationMotivationMotivationMotivationMotivationMotivationMotivationMotivationTraces[striplines(1),microstrips(2),andvias(3)]anddielectric(4)areusedtoroutetime-varyingcurrents(digitalsignals,etc.)aroundonPCBs.ProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinition(1)(2)(3)(4)Traces[striplines(1),microstrips(2),andvias(3)]anddielectric(4)areusedtoroutetime-varyingcurrents(digitalsignals,etc.)aroundonPCBs.Eveniftracesarenotroutedalongtheedge(5),radiationstilloccurs(6).ProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinition(6)(1)(2)(3)(4)(5)Traces[striplines(1),microstrips(2),andvias(3)]anddielectric(4)areusedtoroutetime-varyingcurrents(digitalsignals,etc.)aroundonPCBs.Eveniftracesarenotroutedalongtheedge(5),radiationstilloccurs(6).Weconcludecurrentsinthetracescreateelectromagneticfieldsthatpropagatethroughthedielectrictowardstheedge(7).ProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinition(6)(7)(1)(2)(3)(4)(5)Traces[striplines(1),microstrips(2),andvias(3)]anddielectric(4)areusedtoroutetime-varyingcurrents(digitalsignals,etc.)aroundonPCBs.Eveniftracesarenotroutedalongtheedge(5),radiationstilloccurs(6).Weconcludecurrentsinthetracescreateelectromagneticfieldsthatpropagatethroughthedielectrictowardstheedge(7).Ifweunderstandhowthesefieldsarecreated,howtheypropagatetotheedge,andhowtheyradiateintothesurroundingspaceoncetheygetthere,wecandevelopeffectiveEMCguidelinestominimizeradiation.ProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinitionProblemDefinition(6)(7)(1)(2)(3)(4)(5)Stationary(Electrostatic)Fields–i=dq/dt=0=chargeatrest–OnlyproducestaticE-fields–Example:ChargedcapacitorVelocity(Magnetostatic)Fields–i=dq/dt=constant(DCcurrent)–OnlyproducestaticH-fields–Example:SolenoidconnectedtoabatteryAcceleratingFields–di/dt=d2q/dt2≠≠≠≠0–Producetime-varyingradiatingelectromagneticfields[1],[2]**–Example:Anytimevaryingcurre