如果您无法下载资料，请参考说明：
1、部分资料下载需要金币，请确保您的账户上有足够的金币
2、已购买过的文档，再次下载不重复扣费
3、资料包下载后请先用软件解压，在使用对应软件打开
PortTutorialSeries:CoplanarWaveguide(CPW)StructureCoplanarWaveguideisatransmissionlinesystemconsistingofacentralcurrent-carryingtraceatopasubstrate,coplanarwithsidegroundsextendingbeyondasymmetricgaptoeithersideofthetrace.TherearedifferentkindsofCPWtransmissionlinesusedinRFandmicrowaveapplicationsGroundedCPW(GCPW)willhaveanadditionalgroundplaneontheundersideofthesubstrate.InpracticethisplaneneedstobesufficientlydistantfromthetraceascomparedwiththesidegroundsthatthesystemcarriesaCPWmoderatherthanalossymicrostripmodeUngroundedCPWismorestandard,inwhichthesidegroundscoplanartothestripitselfprovidetheonlyreturncurrentpath,andtheundersideofthesubstrateisunclad.FiniteGroundCPW(FG-CPW)traditionallyreferstoanungroundedCPWinwhichthesidegroundmetalizationisoflimitedwidth,oftennotmorethan2–3timesthewidthofthecentertraceitself,duetospaceconsiderations.AdvantagesCPWhasthesameadvantageasmicrostrip,inthatthesignaliscarriedonanexposedsurfacetrace,onwhichsurface-mountcomponentscanbeattached.Beingasurfacesignalcarrieritalsolendsitselfwelltotestingviaground-signal-groundtypeprobesUnlikemicrostrip,CPW(atleastintheungroundedform)haslittleparasitic（寄生的）lossesbetweensurfacemountedcomponentsandanunderlyinggroundplaneDisadvantagesTheprimarydisadvantageofCPWisthatitishardertodesignwith:featuressuchasopenandshortedstubsarenotassimpleastheyarewithmicrostriporstripline.Additionally,CPWisnotwellsupportedevenbymanymoderntransmissionlinecalculatorsandcircuitsimulatorsWhileobtainingthenecessarydimensionsforaCPWofadesiredcharacteristicimpedanceispossible,oftenthedimensionsoutputbytransmissionlinecalculatorsareimpracticablegivenetchingconstraintsIfthe‘aspectratio’ofaCPW(theratioofitsgaptotracewidths)becomestoohighortoolow,thedesiredCPWmodecanbesupplantedbyparasiticmicrostripmodesorparallelslotlinemodes,resultinginpoorperformanceCoplanarWaveguide:DimensioningHFSSPorts:GeneralRequirementsCPWWavePorts:StartingRecommendationsCPWWavePorts:ImpedanceandCalibrationCPWWavePorts:DesiredExcitationCPW
