LoadPull---ADS(负载牵引详细介绍资料)

AndyHowardApplicationsEngineer28May,2002,LoadPullSimulationUsingADS,Outline,OverviewSpecifyingandgeneratingdesiredloadreflectioncoefficientsAssigningarbitraryreflectioncoefficientsattheharmonicfreqs.BiasingthedeviceandrunningasimulationCalculatingdesiredresponses(deliveredpower,PAE,etc.)Generatingcontourlines,LoadPullSimulationUsingADS,2,LoadPullSimulationUsingADS28May,2002,Page3,Loadpullsimulationvariestheloadreflectioncoefficientpresentedtoadevice.,Varyloadreflectioncoefficient,LoadPullSimulationUsingADS28May,2002,Page4,tofindtheoptimalvaluetomaximizepowerorPAE,etc.,LoadPullSimulationUsingADS28May,2002,Page5,Specifytheloadreflectioncoefficients,Simulationsetupiscomplicated,butregionissampledmoreuniformly,Simulationsetupistrivial,LoadPullSimulationUsingADS28May,2002,Page6,Sweepingrhooveracircularregion,Specifycircularregion,vias11_rhoands11_centervariables,Thisisjustastaticfigure.Itdoesnotgetupdatednorcorrespondtothevaluesintheequations.,Radiusofcircle,Centerofcircle,LoadPullSimulationUsingADS28May,2002,Page7,UseReflectionCoefUtilitydatadisplaytohelpsets11_centerands11_rho,Thecirclecenterandradiusareupdatedwhenyoumoveeitherorbothofthemarkers,LoadPullSimulationUsingADS28May,2002,Page8,Twovariablesareswepttogeneratethepointswithinthedesiredcircle,Theseinitializethesweptvariables,indexs11isthereflectioncoefficient,WillexplainStartandStopequationslater,LoadPullSimulationUsingADS28May,2002,Page9,Moreonthesweptvariables,Variable“imag_indexs11”isthey-axisvalueofsimulatedreflectioncoefficient.Variable“real_indexs11”isthex-axisvalue.Theimag_indexs11variableissteppeduniformly,whereasreal_indexs11issteppednon-uniformly.,Eachpointisadatapair:(real_indexs11,imag_indexs11),m3isatapproximately:(-0.706,0.386),LoadPullSimulationUsingADS28May,2002,Page10,Sweeplimitsfor“imag_indexs11”,Arrowpointstos11_center,imag(s11_center),A,B,Distance“A”=Distance“B”=max_rho-max_rho/(lines+1),LoadPullSimulationUsingADS28May,2002,Page11,Whatis“max_rho”?,LengthofvectorC=mag(s11_center),C,D,LengthofvectorD=1-mag(s11_center),Themax_rhoequationreducestheradiusofthecircleofsimulatedreflectioncoefficientsifanypartofthecirclewouldotherwisebeoutsidetheSmithchart,whichwouldimplyanactiveload.,“max_rho”willbethesmallerofthelengthofvectorDandtheuser-enteredcircleradius,s11_rho.,LoadPullSimulationUsingADS28May,2002,Page12,Whataboutthe“max_rho/(lines+1)”term?,Includingthistermpreventsthefirstandlastlinefrombeingtangenttothecircleatasinglepoint.Thisallowsreal_indexs11tobesweptalongthefirstandlastlinesdefinedbyimag_indexs11.,LoadPullSimulationUsingADS28May,2002,Page13,maximumvalueofc_limit,Sweeplimitsfor“real_indexs11”,Arrowpointstos11_center,real(s11_center),c_limitisthedistancefromtheverticalcenterlineofthecircletotheedges,alongeachofthehorizontallines.Itisdifferentforeachhorizontalline.,min.valueofc_limit,LoadPullSimulationUsingADS28May,2002,Page14,Howisc_limitcalculated?,Arrowpointstos11_center,imag(s11_center),c_limitiscalculatedfrom:r*2=c_limit*2+Y*2,whereY=imag_indexs11-imag(s11_center),andr=max_rho,Circleradiusismax_rho,imag_indexs11,c_limit,LoadPullSimulationUsingADS28May,2002,Page15,Howarethenumberoflinesandthepointsperlinecalculated?,Usersetsthisvalue,The“lines”equationtakesthesquarerootof“pts”,thencomputestheintegerpart.Themax()functionensuresthatatleastonelineisused.Thenumberofpointsperlineiscomputedbykeepingtheintegerpartofpts/lines.,LoadPullSimulationUsingADS28May,2002,Page16,Alternatereflectioncoefficientsweep,Sweepthephaseofthereflectioncoefficient“Phi_rho”indegrees,andsweepthemagnitude“Mag_rho”.“rho”belowbecomesthesweptreflectioncoefficient,insteadofindexs11.,Outline,OverviewSpecifyingandgeneratingdesiredloadreflectioncoefficientsAssigningarbitraryreflectioncoefficientsattheharmonicfreqs.BiasingthedeviceandrunningasimulationCalculatingdesiredresponses(deliveredpower,PAE,etc.)Generatingcontourlines,LoadPullSimulationUsingADS,17,LoadPullSimulationUsingADS28May,2002,Page18,Youcouldmaketheloadindependentoffrequency:,Butthiswouldmodelanunrealisticallysimplesituationandwouldgivesub-optimalresults.,LoadPullSimulationUsingADS28May,2002,Page19,Setsourceandloadimpedancesatharmonicfrequenciesarbitrarily,Thesedefaultvaluesaresomewhatsub-optimal,asusingopensorshortstoterminatetheharmonicsshouldgivebetterperformance.,Z_l_2istheloadimpedanceat2ndharmonic;otherloadandsourceimpedancesdefinedsimilarly,LoadPullSimulationUsingADS28May,2002,Page20,Definingasingle,frequency-dependentreflectioncoefficient(1),The“bruteforce”way,usingagiantif-then-elseequation:,Thisisfromexamples/RF_Board/NADC_PA_prj/NADC_PA_Test,Thesearefrequencybreakpoints,midwaybetweenthefundamentaland2ndharmonic,betweenthe2ndand3rdharmonics,etc.RFfreqisthefundamentalfrequency.,Theseequationsconvertharmonicimpedancestoreflectioncoefficients.,.,LoadPullSimulationUsingADS28May,2002,Page21,Definingasingle,frequency-dependentreflectioncoefficient(2),Usinganarray,definedviathe“list()”function:,Thelistfunctiondefinesanarrayofreflectioncoefficients,thefirstvaluebeing0,thesecondvalueindexs11,thethirdvaluefg(Z_l_2),etc.,Thefunctionfg(x)convertsanimpedancexintoareflectioncoefficient.,LoadPullSimulationUsingADS28May,2002,Page22,Definingasingle,frequency-dependentreflectioncoefficient(2continued),iloadistheindexintothearray.wheniload=1,LoadTuner=LoadArray1=0wheniload=2,LoadTuner=LoadArray2=indexs11wheniload=3,LoadTuner=LoadArray3=fg(Z_l_2)etc.,LoadPullSimulationUsingADS28May,2002,Page23,Howisiloadcalculated?,“freq”isaninternalsimulatorvariable.Fora1-toneload-pullsimulationitwillhavevalues0,RFfreq,2*RFfreq,3*RFfreq,etc.,whereRFfreqisdefinedtobethefundamentalanalysisfrequency.length(LoadArray)=6inthiscase.Sowhenfreq=0,iload=int(min(0/RFfreq+1.5,6)=int(min(1.5,6)=int(1.5)=1Whenfreq=RFfreq,iload=int(min(RFfreq/RFfreq+1.5,6)=int(min(2.5,6)=int(2.5)=2,LoadPullSimulationUsingADS28May,2002,Page24,Moredetails,Whenfreq=0,analysisatDCisbeingcarriedout,andiload=1,soLoadTuner=LoadArray1=0.SothereflectioncoefficientatDCis0.Whenfreq=RFfreq,analysisatthefundamentalfrequencyisbeingcarriedout,andiload=2,soLoadTuner=LoadArray2=indexs11,whichistheloadreflectioncoefficientatthefundamentalfrequency.Whenfreq=2*RFfreq,analysisatthe2ndharmonicfrequencyisbeingcarriedout,andiload=3,soLoadTuner=LoadArray3=fg(Z_l_2),whichistheloadreflectioncoefficientatthe2ndharmonicfrequency.Etc.,LoadPullSimulationUsingADS28May,2002,Page25,Loadpullataharmonicfrequency,Defineanewvariable,Z_l_fund,tofixtheloadimpedanceatthefundamentalfrequency.ThenchangetheLoadArrayequationto:LoadArray=list(0,fg(Z_l_fund),indexs11,fg(Z_l_3),)Thereflectioncoefficientatwhichharmonicfrequencyisbeingswept?Whatifyouwantedtosweepthereflectioncoefficientatthethirdharmonic?,Outline,OverviewSpecifyingandgeneratingdesiredloadreflectioncoefficientsAssigningarbitraryreflectioncoefficientsattheharmonicfreqs.BiasingthedeviceandrunningasimulationCalculatingdesiredresponses(deliveredpower,PAE,etc.)Generatingcontourlines,LoadPullSimulationUsingADS,26,LoadPullSimulationUsingADS28May,2002,Page27,Modifythebiasnetworkasdesired,Butifyoudeletebothcurrentprobesandvoltagelabels“Vs_low”and“Vs_high”thenthePAEcalculationsonthedatadisplaywontwork.,Outline,OverviewSpecifyingandgeneratingdesiredloadreflectioncoefficientsAssigningarbitraryreflectioncoefficientsattheharmonicfreqs.BiasingthedeviceandrunningasimulationCalculatingdesiredresponses(deliveredpower,PAE,etc.)Generatingcontourlines,LoadPullSimulationUsingADS,28,LoadPullSimulationUsingADS28May,2002,Page29,CalculatetheDCpowerconsumption,Theexists()functionreturns0ifthevariableinquotesisnotinthedataset.So,forexample,youcoulddeletethewirelabelVs_low,re-runthesimulation,andthepowerwouldstillbecalculated.IfyoualterthedevicebiasingandstillwanttocalculatetheDCpowerconsumption,youmayneedtomodifytheequationforPdc.,The0indexmeansusetheDCcomponent.,LoadPullSimulationUsingADS28May,2002,Page30,CalculatethepowerdeliveredandPAE,Pavsisthepoweravailablefromthesource,indBm.Theusersetsthisvalueontheschematic,anditispassedintothedataset.Power-addedefficiencyiscalculatedasthepowerdeliveredtotheloadminusthepoweravailablefromthesourcedividedbytheDCpowerconsumption.,0.5*real(V*conj(I)isastandardequationforcalculatingpowerdeliveredtoacomplexload.RefertoDesoerandKuh,BasicCircuitTheory.,LoadPullSimulationUsingADS28May,2002,Page31,Pdel_WattsandPAEarefunctionsofthetwosweptvariables,Themaximumvaluesarecomputedbyfindingthemaximaacrossonedimension(real_indexs11)first,thenfindingthemaximumoftheremainingarray.,Outline,OverviewSpecifyingandgeneratingdesiredloadreflectioncoefficientsAssigningarbitraryreflectioncoefficientsattheharmonicfreqs.BiasingthedeviceandrunningasimulationCalculatingdesiredresponses(deliveredpower,PAE,etc.)Generatingcontourlines,LoadPullSimulationUsingADS,32,LoadPullSimulationUsingADS28May,2002,Page33,Mostsimplecontourlines,Simplestcaseistojustusecontour_polar()functionwithdefaults.Generatessixequally-spacedlevelsbetweentheminimumandmaximumofthedata.Butyoucanteasilyfindthemaximumbymovingthemarkerorquicklychangethenumberoflinesortheirspacing.,LoadPullSimulationUsingADS28May,2002,Page34,Mayspecifyspecificcontourvalues,Usecurlybracestospecifyspecificcontourvalues.Butyoucanteasilyfindthemaximumbymovingthemarker,andyoumayhavetomodifythevaluesbyhandifyouchangethesimulation.,LoadPullSimulationUsingADS28May,2002,Page35,Morecomplexbutmoreflexiblecontourequations,Specifystepin%PAEbetweenlines,Specifynumberofcontourlines,FirstcontourlinewillbeforPAEmax-0.1.This-0.1termisincludedsothefirstlinewillbeasmallcirclethatyoucansee,ratherthanbeingasinglepixelthatyoucant.IfNumPAE_lines=5,then0:(NumPAE_lines-1)generatesanarrayfrom0to4,instepsof1.SothesecondPAElinewillbeforPAEmax-0.1-1*PAE_step.ThethirdPAElinewillbeforPAEmax-0.1-2*PAE_step.Etc.Withthisapproach,youcanquicklychangethenumberoflinesandthespacingbetweenthem.,LoadPullSimulationUsingADS28May,2002,Page36,Generatingcontourlinesforrectangularplots,Thecontour()functiongeneratescontoursforarectangularplot,whichmaygiveyoumoreresolutionthanaSmithchart.,Thesepairsofpointsdefinetheleft-mostarc,Althoughtherightcolumnandy-axisarelabeled“PAE_contours”,theyarereally“imag_indexs11”,LoadPullSimulationUsingADS28May,2002,Page37,GeneratingcontourlinesforSmithchart,Thecontour()functiongeneratesy-axiscoordinates(PAE_contours-reallyimag_indexs11)pairedwithx-axiscoordinates(real_indexs11).ButyouhavetoconvertthesetocomplexnumbersforplottingontheSmithchart.,ThePAE_contours_pequationtakestheXandYcoordinatepairsofthecontourlinesandconvertsthemtocomplexnumbers,X+j*Y,whichcanbeplottedonaSmithchart.ThisequationgeneratescontourlinesfortheSmithchartdirectly:,LoadPullSimulationUsingADS28May,2002,Page38,Generatingcontoursaftersweepingmagnitudeandphaseofrho,PAE_contourscanbeplotted