HFSS基础培训教程——端口和激励

©2011ANSYS,Inc.Allrightsreserved.1ANSYS,Inc.Proprietary©2011ANSYS,Inc.Allrightsreserved.1ANSYS,Inc.ProprietaryHFSS基础培训教程端口和激励ANSYS中国©2011ANSYS,Inc.Allrightsreserved.2ANSYS,Inc.ProprietaryHFSS设计流程DesignSolutionTypeParametricModelGeometry/MaterialsAnalysisSolutionSetupFrequencySweepAnalyzeResults2DReportsFieldsBoundariesExcitationsMeshRefinementSolveMeshOperationsConvergedFinishedUpdateNOYESSolveLoop©2011ANSYS,Inc.Allrightsreserved.3ANSYS,Inc.ProprietaryHFSS端口、激励类型©2011ANSYS,Inc.Allrightsreserved.4ANSYS,Inc.Proprietary端口的含义•计算S参数时信号进入和输出的地方–在端口处加电，在端口处测量–类似于实际测量时的探针•通过探针加电，在探针上测量©2011ANSYS,Inc.Allrightsreserved.5ANSYS,Inc.Proprietary5实测环境中存在的电磁场©2011ANSYS,Inc.Allrightsreserved.8ANSYS,Inc.Proprietary•WavePort–外部端口–通过传输线方式将信号加入结构中–端口定义为传输线的截面，HFSS在端口处求解传输线的特性，得到特性阻抗，用于计算S参数–传输线以端口的形状可以向后无限延展–端口是理想匹配负载•LumpedPort–内部端口–相当于测试系统的内阻，通过测试系统给结构加入信号–使用者指定端口阻抗，端口阻抗设定为测试系统的内阻–实际求解时可以不画出探针结构–端口面所在处有可能产生反射•FloquetPortHFSS可以定义的三种端口WavePort求解微带线LumpedPort求解微带线©2011ANSYS,Inc.Allrightsreserved.9ANSYS,Inc.Proprietary•Solutiontypeselection–Asageneralrule,onecouldchoosethesolutiontypebasedonthetypeoftransmissionlinethatisbeinganalyzed–DrivenModal•Hollowwaveguides(metallicrectangular,circular…etc)•Anyproblemwhereasymmetryboundaryconditionisapplied–DrivenTerminalRecommendedforallSIdesigns•Microstrip,stripline,coax,coplanarwaveguide设置求解类型©2011ANSYS,Inc.Allrightsreserved.10ANSYS,Inc.Proprietary设置求解类型DrivenModal•Fieldsbasedtransmissionlineinterpretation•Port’ssignaldecomposedintoincidentandreflectedwaves•Excitation’smagnitudedescribedasanincidentpowerDrivenTerminal•CircuitBasedtransmissionlineinterpretation•Port’ssignalinterpretedasatotalvoltage(Vtotal=Vinc+Vref)•Excitation’smagnitudedescribedaseitheratotalvoltageoranincidentvoltage•SupportsDifferentialS-ParametersModalPropagation•Energypropagatesinasetoforthogonalmodes•ModescanbeTE,TMandTEMw.r.t.theport’snormal•Mode’sfieldpatterndeterminedfromentireportgeometry•EachModehasitsowncolumnandrowintheS,Y,andZparametersTerminalPropagation•Eachconductortouchingtheportisconsideredaterminaloraground•EnergypropagatesalongeachterminalinasingleTEMmode•EachTerminalhasitsowncolumnandrowintheS,YandZparameters•DoesnotsupportsymmetryboundariesorFloquetPorts*RecommendedforSIdesigns*©2011ANSYS,Inc.Allrightsreserved.11ANSYS,Inc.Proprietary•CalibratingPorts–SolutionType:DrivenTerminal•TheModalS-matrixsolutioncomputedbyHFSSisexpressedintermsoftheincidentandreflectedpowersofthewaveguidemodes.Thisdescriptiondoesnotlenditselftoproblemswhereseveraldifferentquasi-transverseelectromagnetic(TEM)modescanpropagatesimultaneously.Forstructureslikecoupledtransmissionlinesorconnectors,whichsupportmultiple,quasi-TEMmodesofpropagation,itisdesirabletohaveHFSScomputetheTerminalS-Parameters.•TheTerminalS-ParametersareatransformationthatisperformedfromtheModalS-matrixsolution.Becauseofthis,wewillpresentsomeoftheportdetailsrelatedtoModalportdefinitionsasaguidelines.Ifyouarenotusingwaveports,youcanskipthematerialandgodirectlytotheLumpedPortdiscussion.DrivenTerminal©2011ANSYS,Inc.Allrightsreserved.12ANSYS,Inc.ProprietaryTerminalNamingConductorName•NamesterminalbasedonconductoritisassignedPortNameTerminal’sConductornameNumberAssociatedwithPortPortObjectName•Namesterminalbasedonportobject’snamePortObject’sNameTerminalNumberforThisPortAirBoxPortName©2011ANSYS,Inc.Allrightsreserved.13ANSYS,Inc.ProprietaryExcitations:Modalvs.TerminalT1T2IntegrationLineMode1(EvenMode)IntegrationLineMode2(OddMode)ModestoNodesTransformationSPICEDifferentialPairsModalPort1Port2TerminalPort1Port2T1T2T1T22Modes2Modes©2011ANSYS,Inc.Allrightsreserved.14ANSYS,Inc.ProprietaryWavePort14©2011ANSYS,Inc.Allrightsreserved.15ANSYS,Inc.Proprietary•WavePort是传输线的截面，信号通过传输线进入结构–端口面所在位置就是参考面，对计算S参数的相位很重要–对于包含开放结构的传输线（如微带线）可建立二维物体用以定义端口•WavePort所定义的位置上，场只能是单向存在的–整个结构的最外面，与背景相交接–与理想导体相交接•WavePort的边是PerfectEWavePort的定义求解空间非求解空间©2011ANSYS,Inc.Allrightsreserved.16ANSYS,Inc.Proprietary•WavePort的边缘相当于PerfectE–对于外围是开放结构的传输线，端口要做够大，避免端口边缘与信号线产生耦合，影响传输线的特性•端口所在的面不能被金属层穿越分割–将造成端口场分布的变化，使得求解模式不是预想的结果WavePort设置时的注意事项错误的定义：地平面将传输线分割成两部分AB正确左右过窄高度不足©2011ANSYS,Inc.Allrightsreserved.17ANSYS,Inc.Proprietary•WavePorts只能定义在没有场分布的区域。–定义在仿真对象和背景交接处–定义在理想导体表面•以简单的2-port波导为例：–端口设定在波导的端截面处。–端口面积需限制在波导截面内。–选择表面或相应的2D物体来定义端口。WavePort表面©2011ANSYS,Inc.Allrightsreserved.18ANSYS,Inc.Proprietary–WavePorts需要一段横截面具有连续性的长度•HFSS假设每一个定义的端口都连接到一个半无限长且具有与端口形状相同的截面的波导上.•当对S参数求解时，仿真器假设的激励源是自然辐射场（包含多模）在端口横截面的叠加.Port1Port2Port3Port4©2011ANSYS,Inc.Allrightsreserved.20ANSYS,Inc.Proprietary•WavePort距离不连续性应当有充分的距离–在模型中保留一段均匀传输线–确保凋落高阶模式充分衰减–通过“Ports-onlySolution”计算所需长度WavePort设置时的注意事项nouniformcrosssectionatWavePortsuniformcrosssectionaddedforeachWavePort©2011ANSYS,Inc.Allrightsreserved.21ANSYS,Inc.Proprietary•包含一段横截面具有连续性的长度，使高次模得到足够的衰减.•EvanescentWaves的传输系数为e-z（为衰耗系数，Z为位移）•可选:通过“Ports-onlySolution”先得出高次模的衰耗系数。•利用公式20log(e-z)=-20dB计算使得高次模衰减至可忽略不计的距离。•利用以上计算得到的位移z调整端口的延伸长度。端口延伸和高次模问题©2011ANSYS,Inc.Allrightsreserved.22ANSYS,Inc.Proprietary•单根微带传输线–宽度为微带线宽度w的5倍，或者介质高度h的三倍，左右对称•取5w和3h较大的–高度为介质高度的5倍到10倍左右–端口的下边从地平面向