HFSS-中的三种辐射边界比较

Tips:HFSS中的三种辐射边界February1,2012ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February23,2009Inventory#002593©2012ANSYS,Inc.4-44Release14.0•Mimicscontinuedpropagationbeyondboundaryplane–Absorptionachievedvia2ndorderradiationboundary–Absorbsbestwhenincidentenergyflowisnormaltosurface–Distancefromradiatingstructure–Placeatleast/4fromstronglyradiatingstructure–Placeatleast/10fromweaklyradiatingstructure–MustbeconcavetoallincidentfieldsfromwithinmodeledspaceRadiationBoundaryBoundaryis/4awayfromhornapertureinalldirectionsFebruary1,2012ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February23,2009Inventory#002593©2012ANSYS,Inc.4-45Release14.0RadiationBoundary:IncidenceAngleDependencyRadiationboundaryfunctionswellforincidentangleslessthan25°-30°RadiationBoundaryRadiationBoundaryPoorabsorptionofradiationboundaryaffectsradiationpatternFebruary1,2012ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February23,2009Inventory#002593©2012ANSYS,Inc.4-46Release14.0•RadiationBoundaryseparationdistance–Exampleprobe-fedcircularpatch–Varieddistancebetweenabsorbingboundarycondition(ABC)andantenna•λ/20,λ/10,λ/8,λ/4,λ/2,3λ/4,λ–ExaminedimpactonreturnlossandgainRadiationBoundary’sLocation/4andcaseswithin13MHzofeachother(0.1%)0.2dBvariationFebruary1,2012ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February23,2009Inventory#002593©2012ANSYS,Inc.4-47Release14.0•PerfectlyMatchedLayer–Fictitiouslossyanisotropicmaterialwhichfullyabsorbselectromagneticfields–TwotypesofPMLapplications•“PMLobjectsacceptfreeradiation”ifPMLterminatesfreespace•“PMLobjectscontinueguidedwaves”ifPMLterminatestransmissionline–GuidelinesforassigningPMLboundaries•UsePMLsetupwizardformostcases•ManuallycreateaPMLwhenbaseobjectiscurvedorinhomogeneous–ParameterstoDefine:•DefinePMLThickness•SpecifyMinimumFrequency(FromSweep)•SpecifyMinimumDistancefromAntennatoPML(MeasureinModel)PerfectlyMatchedLayer(PML)February1,2012ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February23,2009Inventory#002593©2012ANSYS,Inc.4-48Release14.0•PMLSetupWizard–Helpscreateobjectswithappropriatematerialproperties•PMLInputs–UniformLayerThickness•ThicknessofPMLObjectCreated(recommendedλ/3)–MinimumFrequency•MinimumfrequencythatPMLwillbeabsorbing–MinimumRadiatingDistance•DistancefromradiatingobjecttoPMLObject(recommendedλ/8)PMLSetupWizard12PMLObjectMinimumRadiatingDistanceUniformLayerThicknessAirBoxPMLCornerObjectRadiatingElementFebruary1,2012ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February23,2009Inventory#002593©2012ANSYS,Inc.4-49Release14.0PMLIncidenceAngleDependencyPMLfunctionswellforincidentangleslessthan65°-70°BetterabsorptionleadstobetterconsistencyinthepatternsPMLPMLBlueTraceiswiththickerPMLFebruary1,2012ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February23,2009Inventory#002593©2012ANSYS,Inc.4-50Release14.0•PMLseparationDistance–Exampleprobe-fedcircularpatch–VarieddistancebetweenPMLandantenna•λ/20,λ/10,λ/8,λ/4,λ/2,3λ/4–ExaminedimpactonreturnlossandgainPML’sLocation/8and3/4caseswithin28MHzofeachother(0.3%)February1,2012ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February23,2009Inventory#002593©2012ANSYS,Inc.4-51Release14.0Facelist积分面通过自定义积分面，可提高远场求解精度。February1,2012ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February23,2009Inventory#002593©2012ANSYS,Inc.4-52Release14.0HybridFiniteElement–IntegralEquationsFiniteElementMethod•HFSS•Efficientlyhandlescomplexmaterialandgeometries•HybridFiniteElement-IntegralEquations•FE-BI•IE-Regions•HybridmethodinvokedinsideofHFSSDesignusingIE-RegionsorFE-BIboundaryconditions•HybridmethodtakesadvantageoffeaturesfrombothmethodstoallowformoreefficientsimulationsFE-BIIE-RegionsIntegralEquations•HFSS-IE•EfficientsolutiontechniqueforopenradiatingandscatteringofmetallicobjectsFebruary1,2012ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February23,2009Inventory#002593©2012ANSYS,Inc.4-53Release14.0•Meshtruncationofinfinitefreespaceintoafinitecomputationaldomain–AlternativetoRadiationorPML•HybridsolutionofFEMandIE–IEsolutiononouterfaces–FEMsolutioninsideofvolume•FE-BIAdvantages–Arbitraryshapedboundary•Conformalanddiscontinuoustominimizesolutionvolume–Reflection-lessboundarycondition•Highaccuracyforradiatingandscatteringproblems–Notheoreticalminimumdistancefromradiator•ReducesimulationvolumeandsimplifyproblemsetupFiniteElement–BoundaryIntegralFEMSolutioninVolumeIESolutiononOuterSurfaceFieldsatoutersurfaceIterateFreespaceFE-BIArbitraryshapeFebruary1,2012ANSYS,Inc.Proprietary©2009ANSYS,Inc.Allrightsreserved.February23,2009Inventory#002593©2012ANSYS,Inc.4-54Release14.0•Notheoreticalminimumdistancefromradiator•AdvantageoverABC•Easysetupforbroadbandfrequencysweeps–Reflectionlessboundarycondition•Abilitytoabsorbincidentfieldsisnotdependentontheincidentangle•HighlyadvantageousoverABCboundarycondition–Arbitraryshapedboundary•Outwardfacingnormalscanintersect•Cancontainseparateddomains•ConformalboundarycaneliminateairvolumerequiredwhenusingPMLsorABCs–FE-BIcomeswithacomputationalcost•Ability