匹配和调谐Matching and Tuning

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1、Chapter3MatchingandTuningByProfessorSyedIdrisSyedHassanSchofElect.&ElectronEngEngineeringCampusUSMNibongTebal14300SPSPenang©ProfSyedIdrisSyedHassanWhymatchingortuningisimportant?Tomaximizepowerdeliveryandminimizepowerloss.ToimprovesignaltonoiseratioasinsensitivereceivercomponentssuchasLNA,antenna,

2、etc.Toreduceamplitudeandphaseerrorasindistributednetworksuchasantennaarray.BasicideaofimpedancematchingConceptofmaximumpowertransferPowermaximumwhenceZL=ZoPowerdeliveratZLisInlumpcircuitcontinueIntransmissionlineNoreflectionwhenceZL=Zo,henceTheloadZLcanbematchedaslongasZLnotequaltozero(short-circui

3、t)orinfinity(open-circuit)TheimportantparameterisreflectioncoefficientFactorsinselectingmatchingnetworkComplexity:simpler,cheaper,morereliableandlowlosscircuitispreferred.Bandwidth:matchoveradesirablebandwidth.Implementation:dependontypesoftransmissionlineeithercable,stripline,microstripline,wavegu

4、ide,lumpcircuitetc.Adjustability:somenetworkmayneedadjustmenttomatchavariableload.MatchingwithlumpedelementsThesimplestmatchingnetworkisanL-sectionusingtworeactiveelementsConfiguration1WhenceRL>ZoConfiguration2WhenceRL

5、sinunitycircle,configuration1isused.Otherwiseconfiguration2isused.Thereactiveelementsareeitherinductorsorcapacitors.Sothereare8possibilitiesformatchingcircuitforvariousloadimpedances.Matchingbylumpedelementsarepossibleforfrequencybelow1GHzorforhigherfrequencyinintegratedcircuit(MIC,MEM).Impedancesf

6、orseriallumpedelementsSerialcircuitReactancerelationshipvalues+veX=2pfLL=X/(2pf)-veX=1/(2pfC)C=1/(2pfX)ImpedancesforparallellumpedelementsParallelcircuitSusceptancerelationshipvalues+veB=2pfCC=B/(2pf)-veB=1/(2pfL)L=1/(2pfB)LumpedelementsformicrowaveintegratedcircuitSpiralinductorLoopinductorInterdi

7、gitalgapcapacitorPlanarresistorChipresistorMetal-insulator-metalcapacitorChipcapacitorMatchingbycalculationforconfiguration1Formatching,thetotalimpedanceofL-sectionplusZLshouldequaltoZo,thusRearrangingandse