脉冲功率技术基础61传输线

脉冲压缩与成形技术－－－传输线基础知识Load

通过传输线向负载传输能量TransmissionLinesClass6TransmissionLineConceptPowerPlantConsumerHomePowerFrequency(f)is@60Hz

Wavelength(l)is5106m

(Over3,100Miles)TransmissionLineCouldbeconsideredasNon-TransmissionLineTransmissionLinesClass6PCTransmissionLinesIntegratedCircuitMicrostripStriplineViaCrosssectionviewtakenherePCBsubstrate

TWCrossSectionofAbovePCB

TSignal(microstrip)Ground/PowerSignal(stripline)Signal(stripline)Ground/PowerSignal(microstrip)CopperTraceCopperPlaneFR4DielectricWSignalFrequency(f)is

approaching10GHz

Wavelength(l)is1.5cm

(0.6inches)Micro-

StripStripline

电磁波按一定速度传播（最大光速c）TransmissionLinesClass6WhendoesaT-lineeaT-Line?Whetheritisabumporamountaindependsontheratioofitssize(tline)tothesizeofthevehicle(signalwavelength)Whendoweneedtousetransmissionlineanalysistechniquesvs.lumpedcircuitanalysis?TlineWavelength/edgerateSimilarly,whetherornotalineistobeconsideredasatransmissionlinedependsontheratiooflengthoftheline(delay)tothewavelengthoftheappliedfrequencyortherise/falledgeofthesignal

水波传播示意图

传输线具有分布参数

传输线分布电感

传输线分布电容

沿传播方向分布电阻两传输线之间存在泄漏电流引起泄漏电阻

传输线分布参数示意图

分布参数示意图

直流电压下传输线充电过程传播过程

交流电压下充电过程充电电荷：Q=IT=CE

（1）充电电压：(2)ET=LI

（3）(1)*(3)电压、电流关系传输时间T：波速：波阻抗(特征阻抗Z）TransmissionLinesClass6IdealTransmissionLineParametersKnowinganytwooutofZ0,Td,C0,andL0,theothertwocanbecalculated.C0andL0arereciprocalfunctionsofthelinecross-sectionaldimensionsandarerelatedbyconstantme.

eiselectricpermittivity

e0=8.85X10-12

F/m(freespace)

erisrelativedielectricconstant

mismagneticpermeability

m0=4pX10-7

H/m(freespace)

mrisrelativepermeability.;;;1;;;;0000000000000d000eeemmmmemerrLCvTZLZTCCLTCLZ========Don’tforgettheserelationshipsandwhattheymean!TransmissionLinesClass6ParallelPlateApproximationAssumptionsTEMconditionsUniformdielectric(e

)betweenconductorsTC<<TD;WC>>TDT-linecharacteristicsarefunctionof:MaterialelectricandmagneticpropertiesDielectricThickness(TD)Widthofconductor(WC)Trade-offTD

;C0,L0,Z0WC

;C0,L0,Z0Toafirstorder,t-linecapacitanceandindu