通讯Cable连接器介绍概要

AmphenolRFAsiaConnectorOverviewTrainingMay5,2003ConnectorAnatomy•WhatisaConnector?•Aconnectorisadeviceusedtoconnecttocablesorotherdevicesthroughwhichelectromagneticenergyistransferredfromoneplacetoanother•Body-Contact-InsulatorBodyContactInsulatorConnectorAnatomyDiscontinuityCompensationStepsDielectricSupportBeadContactBarbSlottedContactCableAnatomy•WhatisCable?•Cableisatransmissionlinethroughwhichelectromagneticenergyispropagatedandtransferredfromoneplacetoanother•Jacket-Braid-Shield-Dielectric-CenterConductorConductorDielectricJacketShieldBraidAssistanceontheWebAmphenolRFNewsletterTechnicalQuestions:VSWRConversionCharts:Glossary:•Whatisatransmissionline?•Atransmissionlineisaconduitbywhichelectromagneticenergyistransferredfromoneplacetoanother•CoaxialCable-UnbalancedLine:Centerconductorsurroundedbyaconcentricdielectricandouterconductor-Mostpopulartypeoftransmissionline#1.TransmissionLine•Whatisatransmissionline?•Atransmissionlineisaconduitbywhichelectromagneticenergyistransferredfromoneplacetoanother•Waveguide:Rectangular,Circular#1.TransmissionLine•Whatisatransmissionline?•Atransmissionlineisaconduitbywhichelectromagneticenergyistransferredfromoneplacetoanother•PlanarTransmissionLine:Microstrip,Stripline,Coplanarwaveguidearemostcommon#1.TransmissionLine•Whatisatransmissionline?•Atransmissionlineisaconduitbywhichelectromagneticenergyistransferredfromoneplacetoanother•TwinLine-balancedline:twoparallelconductorsseparatedbyadielectric..#1.TransmissionLine•Thetypeoftransmissionlinewilldeterminetheconnectorstyle•CableConnector-CoaxialCable,TwinLine•SurfaceMountConnector-Microstrip•TabLaunchConnector-Microstrip,Stripline,Coplanar•EndLaunchConnector-Microstrip,Coplanar•PinLaunchConnector-Microstrip,Stripline,Coplanar#2.ImpedanceOhm’sLaw#2.ImpedanceImpedance:TheimpedanceoftheconnectorgenerallymustmatchthatofthetransmissionlineNon-Constant50,75ohm50ohm75ohmBNCTwinaxialBNC7/161.6/5.6UHFSMBC,SC,HNTypeFTwinaxialMCXMini-UHFTypeG1.0/2.3MMCXTNCSMANOuterDiameterInnerDiameterDielectricConstantImpedance.063.0202.050Ohms.063.0122.075Ohms.276.1201.050Ohms#3.FrequencyRange•Frequencyisthenumberofelectromagneticwavesthatpassagivenpointin1second•Hertzistheunitoffrequencymeasurement•Generally,theRFperformanceofaconnectordegradesasthefrequencyisincreased(c=f)•Wavelengthdecreases,thereforesmallerdisruptionscausemoreproblems•Specifyingthefrequencywillmakeiteasierforthedesignengineertooptimizetheperformance•Wheneverpossible,don’tspecifyahighfrequencyconnectorwhenalowfrequencyconnectorwillworkdothejob#3.FrequencyRangeGiga=1,000,000,000BillionMega=1,000,000MillionKilo=1,000ThousandMilli=1/1000OnethousandthMicro=1/1,000,000OnemillionthNano=1/1,000,000,000OnebillionthPico=1/1,000,000,000,000Onetrillionth34445.26671010111112.41826.50.10.20.332.51051015202530BNCTwinTwinaxUHF1.6/5.6Mini-UHFTypeGTypeFSMBBNC1.0/2.3(PushPull)7/16(Corrugated)MMCXMCX7/16(Coax,SR)SMC1.0/2.3(Threaded)TNCNSMA(FlexCoax)SMA(SR)SMA(HiPerf.)FrequencyChart(GHz)#4.ReturnLossorVSWR•AmeasureofhowmuchpowerisreflectedReturnLoss:Theportionofasignalthatislostduetoareflectionofpoweratalinediscontinuity.ReturnLossissimilartoVSWRandisgenerallypreferredintheCATVindustrytoaVSWRspecification•VSWR:AcronymforVoltageStandingWaveRatio.VSWRistheratioofvoltageappliedtovoltagereflected.Itisthemajorfactorcontributingtothetotalsignalefficiencyoftheconnector.•Bestperformanceisachievedwhentheimpedanceofthecableandtheconnectorarethesame(matched)ComponentCablePowertransmittedintocomponentIncidentPowerReflectedPowerReturnLoss=RatioofreflectedtoincidentpowerindBVSWR=Ratioofmaximumtominimumelectricfield(Voltage)#5.InsertionLoss•InsertionLossisexpressedindB,andisameasureofthetotallossofpowergoingthroughadevice•IL=-20*log(Pout/Pin)•Includeslossesduetoreflection(usuallythedominantfactorunlesstheReturnLossisverylow-26dB),pluslossesduetothedielectricandmetalconductors(Attenuation)•LongCableassembly-Connectorinsertionlossnotusuallysignificant•Shortcableassembly-Connectorinsertionlosscanbesignificant•Typically,connectorinsertionlossisverysmall(.1-.25dB)