中英文中英文文献翻译-RFID的历史Word文件下载.docx

中英文中英文文献翻译-RFID的历史Word文件下载.docx

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@#@ThehistoryofRFID@#@Whetherwerealizeitornot,radiofrequencyidentification（RFID）isanintegralpartofourlife.RFIDincreasesproductivityandconvenience.RFIDisusedforhundreds,ifnotthousands,ofapplicationssuchaspreventingtheftofautomobilesandmerchandise;@#@collectingtollswithoutstopping;@#@managingtraffic;@#@gainingentrancetobuildings;@#@automatingparking;@#@controllingaccessofvehiclestogatedcommunities,corporatecampusesandairports;@#@dispensinggoods;@#@providingskiliftaccess;@#@trackinglibrarybooks;@#@buyinghamburgers;@#@andthegrowingopportunitytotrackawealthofassetsinsupplychainmanagement.RFIDtechnologiesisalsobeingpressedintoserviceforuseinU.S.HomelandSecuritywithapplicationssuchassecuringbordercrossingsandintermodalcontainershipmentswhileexpeditinglow-riskactivities.@#@RFIDisatermcoinedforshort-rangeradiotechnologyusedtocommunicatemainlydigitalinformationbetweenastationarylocationandamovableobjectorbetweenmovableobjects.AvarietyofradiofrequenciesandtechniquesareusedinRFIDsystems.RFIDisgenerallycharacterizedbyuseofsimpledevicesononeendofthelinkandmorecomplexdevicesontheotherendofthelink.Thesimpledevices（oftencalledtagsortransponders）aresmallandinexpensive,canbedeployedeconomicallyinverylargenumbers,areattachedtotheobjectstobemanaged,andoperateautomatically.Themorecomplexdevices（oftencalledreaders,interrogators,beacons）aremorecapableandareusuallyconnectedtoahostcomputerornetwork.Radiofrequenciesfrom100kHzto10GHzhavebeenused.@#@ThetagsareusuallybuiltusingCMOScircuitrywhileothertechnologiescanbeusedsuchassurfaceacousticwave（SAW）devicesortunedresonators.Tagscanbepoweredbyabatteryorbyrectificationoftheradiosignalsentbythereader.Tagscansenddatatothereaderbychangingtheloadingofthetagantennainacodedmannerorbygenerating,modulating,andtransmittingaradiosignal.Avarietyofmodulationandcodingtechniqueshavebeenused.RFIDsystemscanbereadonly（dataistransferredonlyinonedirection,fromthetagtothereader）orreadandwrite（two-waycommunication）.@#@AtypicalRFIDsystemcanusetheprincipleofmodulatedbackscatter（seeFig.1）.InthistypeofRFIDsystem,totransferdatafromthetagtothereader,thereadersendsanun-modulatedsignaltothetag.Thetagreadsitsinternalmemoryofstoreddataandchangestheloadingonthetagantennainacodedmannercorrespondingtothestoreddata.Thesignalreflectedfromthetagisthusmodulatedwiththiscodedinformation.Thismodulatedsignalisreceivedby thereader,demodulatedusingahomodynereceiver,anddecodedandoutputasdigitalinformationthatcontainsthedatastoredinthetag.Tosenddatafromthereadertothetag,thereaderamplitudemodulatesitstransmittedradiosignal.Thismodulatedsignalisreceivedbythetaganddetectedwithadiode.Thedatacanbeusedtocontroloperationofthetag,orthetagcanstorethedata.Asimplediodedetectorallowsthedetectioncircuitryinthetagtobesimpleandconsumelittlepower.@#@Mankind’suseandunderstandingofelectricity,magnetism,andelectromagneticinveryearlytimeswaslimitedtohiseyesight,observationofelectrostaticdischarge（don’tstandunderalargetreeduringalightningstorm）,andthemagneticpropertiesoflodestones.Earlyapplicationsprobablyincludedmakinglightwithfire,useofmirrorsforsignaling,anduseoflodestonesfornavigation.@#@Scientificunderstandingprogressedveryslowlyuntilaboutthe1600s.Fromthe1600sto1800stherewasanexplosionofobservationalknowledgeofelectricity,magnetism,andopticsaccompaniedbyagrowingbaseofmathematicallyrelatedobservations.The1800smarkedthebeginningofthefundamentalunderstandingofelectromagneticenergy.In1846,EnglishexperimentalistMichaelFaradayproposedthatbothlightandradiowavesareaformofelectromagneticenergy.In1864,ScottishphysicistJamesClerkMaxwellpublishedhistheoryonelectromagnetic.In1887,GermanphysicistHeinrichRudolfHertzconfirmedMaxwell’selectromagnetictheoryandproducedandstudiedelectromagneticwaves（radiowaves）.Hertziscreditedasthefirsttotransmitandreceiveradiowaves,andhisdemonstrationswerefollowedquicklybyAleksandrPopovinRussia.@#@In1896, GuglielmoMarconidemonstratedthefirstsuccessfultransmissionofradiotelegraphyacrosstheAtlantic,andtheworldwouldneverbethesame.@#@Forwardto20thcentury@#@In1906,ErnstF.W.Alexandersondemonstratedthefirstcontinuouswave（CW）radiogenerationandtransmissionofradiosignals.Thisachievementmarksthebeginningofmodernradiocommunication,whereallaspectsofradiowavesarecontrolled.Theearly20thcenturywasconsideredthebirthofradar.Thewo