外文翻译--无芯片标签，下一个RFID前沿 英文版.pdf

ChiplessTags,theNextRFIDFrontierS.Tedjini,E.Perret,V.Deepu,andM.Bernier1IntroductionEveniftheconceptofRadioFrequencyIDentification(RFID)wasintroducedmanydecadesago1,itisstillveryattractiveandfertileintermofR&Dandnewap-plications2.Today,RFIDisseenasaveryenablingtechnologyanditisunderconsiderationforthousandsofapplicationscoveringalargevarietyofdomainsamongthem:IDpapers,security,accesscontrol,roadtoll,ticketing,pharmacy,logistic,manufacturing,gambling,etc.3Duetotheirrelativelowcostandlargedistanceofcommunication,passive(i.e.,batteryless)UHFtagsareverypromising.Thecrucialissuesofcost,efficiency,reliability,security,andstandardsareunderconsiderationbyseveralgroupsworldwide3.Researchonpassivetags,particularlyUHFtags,isstillveryactiveinordertoen-sureinteroperability,low-costrequirement,anddatasecurity.Theinteroperabilityisneededsincetherearethreefrequencybandsworldwide.Roughly,theoperatingfrequencybands865869MHzforEurope,902928MHz,forAmericasandUSA,952954MHzinJapan,China,andmostofAsia4.TheinteroperabilityrequiresthedevelopmentofefficientminiaturizedantennaabletocoverthethreeRFIDUHFBands.PrivacyishighlydependantonthesecurityofthedatacontainedintheRFIDChip.Today,differentmicroelectronictechnologiesareavailableformanufacturingRFIDchips:CMOS,ASIC,andEEPROMarethebestknownexamples4,5.AstheIFF6(IdentificationofFriendorFoe)wasthefirstapplicationofRFID,dur-ingWorldWarII,theAlliesusedthecryptographyonIFFtransponders.IntodaysRFID,chipon-tagcryptographyisgenerallydesirableandcanbeimplementedinmanyapplications.However,on-tagcryptographyisstillprohibitivewhenitvio-latesapplicationrequirements,suchaspowerorcostconstraints7.Thethirdissueconcernsthecostofthetag.InadditiontothecostoftheRFIDICandtheantenna,thecostofthetagwilldependontheconnectionmanufacturingprocessbetweentheantennaandtheICRFIDChip.EvenifmuchprogresshasbeenmadeinantennaS.Tedjini(enc-12),E.Perret,V.Deepu,andM.BernierGrenoble-inp/LCIS,ESISAR,F26902Valence,Francee-mail:smail.tedjinilcis.grenoble-inp.frD.Giustoetal.(eds.),TheInternetofThings:20thTyrrhenianWorkshoponDigitalCommunications,DOI10.1007/978-1-4419-1674-723,cCRSpringerScience+BusinessMedia,LLC2010239240S.Tedjinietal.costreductionusinglow-costsubstrateandinkprinting8ofatleastapartoftheantenna,theinterconnectionbetweenantennaandRFIDICportsstilldemandsbet-terreliability9,10.Onealternativeforbetterdatasecurityandlow-costobjectiveistoconsiderChiplesssolutions.RecentlymanydesignsofchiplessRFIDsinthemicrowaveregionhavebeenreportedinliterature.MicrowavetagsorRFtagshaveobviousadvantagesoflongerrangecomparedtoopticalbarcodesandareeasytobefabri-catedbyconventionallithographictechniques.Thisisaveryinterestingapproachunderdevelopmentinmanylabs.Inthiscommunication,wediscussdifferentapproachesandadvancesforUHFtagdesign.Section2willdiscussthetraditionaltagsbasedonRFIDchip.Section3isdedicatedtochipless.BothRFandTHzchiplesspossibilitiesarepresentedanddiscussed.Somesimulationresultsofnewlyproposedstructuresarereported.2TraditionalRFIDTagNowadays,UHFRadioFrequencyIdentification(RFID)technologyisgeneratingmuchinterestinindustrialandacademicinstitutionsowingtoitsimmensepotentialintracking.ThisiswhythedesignofUHFRFIDtagswithhighperformancesandlowcostisaveryactivefieldofresearch.UHFtagswithrelativelylowcosthavebeeninplaceforthelast10years.How-ever,thedeploymentinhigh-volumeofthistechnologyisstillheldbackbytherelativelyhighcostofthesetags.Thisisapartofthesituation,butitisnottheonlyreason.Indeed,ifweconsiderthecaseofHFRFID,onecannoticethatsuchtagsarerelativelyclosetotheUHFtagsregardingmanufacturingprocess,technologyandinsitumaterials.Thesetagsarealsocomposedofasiliconchipandmetalstripsforcommunicatingwiththereader,andthusthecostsofbothofthesetags(UHandUHF)arecomparable.Butthefieldofapplicationisquitedifferent.TheHFtagsareusedforshort-rangeapplications.However,ifweconsiderthemassmarket,inspiteofthisrealhandicap(formaintenanceorhandlingreason,itisgenerallybettertobeabletoreadalltagsinvolvedinaspecificarearemotely),HFtagsarestillthemostinvolvedinthissector.Thereasonforthisisnoteconomical(tagspricesarecomparable)buttechnical.Indeed,inrealsituation,theHFtagsaremorerobustthantheUHFtags.Thishasanextremelyimportantimpactforthefinaluser:withoutpreliminarytest,auniqueHFtagcanbeusedwithaverygreatnumberofobjects.Forexample,inpractice,theRFIDsystemoperationwillnotbedisturbediftheobject,onwhichthetagisplaced,containsmetalsornot.InthecaseofUHF,theenvironment(theobjectonwhichthetagisplaced,aswellasthecloseenvironment)inwhichthetagsareusedaffectstheircharacteris-ticsconsiderably.Inparticular,whenthetagisplacedinanenvironmentdifferentfromwhichitwasspecificallydesignedfor,theperformancesofthesystemcanberapidlydamaged,andthusthepotentialforthistechnologyislimited.However,ChiplessTags,theNextRFIDFrontier241weremindthatthisapplicationwouldbeviablefordetectioninabout99%cases.Generalobservationscouldleadonetonoticethattrackingobjectshaveneitherthesameelectromagneticproperties,northesamegeometricalsize.Moreover,consid-eringthetrendofnewapplications,itisexpectedthatthetagswillbeintegrateddirectlyintheobjectitself.Indeed,itisinterestingtofollowtheobjectthroughoutitsdifferentmanufacturesteps,butalsothroughoutthesupplychain.Therefore,itisimportanttodevelopnewRFIDtagdesigntoolstopromotethedeploymentinmass-volumeoftheUHFRFIDtechnology.Thetool,onwhichweareworking11,isabletoautomaticallydesignthetagaccordingtouserspec-ifications.TheinputsbytheuserarethegeometricalsizeofthefinaltagandthepropertiesoftheUHFRFIDchipfrontend.Dependingontheuserrequirements,onwherethetagwillbeused(permittivity,metal,etc.),theapplicationreturnsthetopologyofthetag,whichcanbeuseddirectlyforthemanufacturing.Antennasdesignsolutionsrestonpurelyempiricaldesignapproaches,basedonfoldeddipoleantennasandcurrentloop(formatchingandnearfieldconsiderations).Wedevelopanewdesignapproachwheretheuserrequirementstakepartinthede-signoftheantenna.Theantennatopologyisnotdefinedaprioriasintheclassicalmethods.Originaltopologiesofantennasaregeneratedautomaticallyandselectedaccordingtotheconstraints.SomeexamplesaregiveninFig.1.Thisapproachdoesnotsimplyconsistinoptimizingatopologyalreadyselected,butindesigningtheantennafrombeginningtoend.Ourapproachcombinesgeneralpurposesoftware(forexample,MATLABRCR)withsoftwarededicatedtoEMsimulations(forexam-ple,ANSOFTDESIGNERRCR).Themainmotivationfortheintegrationofthesetwotypesofsoftwareistobenefitfromdataprocessing,theverybroadpaneloffunctions(forexamplefunctionsofoptimization),alongwithpowerfulandverygeneral-purposeelectromagneticsimulators.AllthecommandsarecontrolledfromMATLABRCRwhatmakesthisapproachveryflexible.So,thedesignercanavoidmanualrepetitivetasksaswellasthetediousparameterizations.WeuseanoptimizationprocessbasedontheconceptofGeneticAlgorithms(GA)tosatisfytheconstraintssetduringthedesignprocess.Theoptimizationcon-sistsofaniterativeprocess,whichfirstgeneratestheantennashape,thensimulatesitandfinelyevaluatesitsperformanceaccordingtotheimposedconstraints.Thus,theantennashapechangesduringiterationonanevolutionaryprinciple.Thisisre-peateduntilanantennadesign,whichsatisfiestheprojectspecification(asgoodFig.1Examplesofautomaticantennadesigns:(1)symmetric(2)asymmetric(3)sectorizationmethod(meanderedzoneindashline)242S.Tedjinietal.aspossible)isobtained.Thisveryflexibleapproachmakesitpossibletotakeintoaccountthedifferentissuesthroughoutthedesignprocess,andspecially,thephysi-calenvironmentofthetag11.3ChiplessSolutionsChiplessRFIDisanemergingareaofRFIDtechnologyforultra-low-costRFIDapplications.However,itiscurrentlyconfinedtotheunlicensedradiofrequencybands.Inthissection,wepresentdifferentapproachesforchiplesssolutions,in-cludingsomealternativetoconsiderhigherfrequencies,namelytheTHzdomain.3.1ChiplessMethodsThemostpopulartagsonthemarket(themostsoldtoo)arethepassivetags.Thisfamilyoftagshasachievedtremendousgrowth,althoughunitcostsstillremainhigh,hinderingtheirdevelopment1.Thisiswhytagswithoutchip(chipless)haveappearedandmakingitpossibletoreducethecostinalargewaytomakethemcompatiblewiththeAutoIDCenterrecommendations.Inadditiontothepriceofthechip,thisapproachallowstodrivedownchip-assemblycost.Theseelementsmakeuptomorethanhalfofthepriceofthetraditionaltag12.Chiplesstags,alsonamed“RFbarcode”,areusuallymanufacturedwithlowcostmaterials,generallyelectromagneticreflectiveorabsorptivematerials.Chip-lesstags,comparedtopassivetags,generallyhavethefollowingcharacteristics:SIlowcost,lessthan5centsinvolume,SIcontactless,shortrangeslessthan1m,SIbetterreliability:thermalandmechanicalbehavioursHowever,theseadvantagesshouldbebalancedwiththelimitedstoragecapacity(afewtensofbits)andthenon-rewriteablecharacteristic(Read-OnlyTags)ofthesedevices.Anotherdrawbackisthecostofthereader,whichcouldbehighercomparedtochip-basedreaders.Chiplesstagsarecomposedofdifferentfamilies,basedonvariousapproaches.Themostpromisingarebasedon:1.Theacousto-opticspropertiesofmaterials,morepreciselyonsurfaceacousticwave(SAW)13.Thisapproachalreadycommercializedisbyfarthemostma-turechiplessRFIDtechnology.2.Printedorganictransistors.ThisprospectiveapproachismainlybasedonthesameprincipleofpassiveRFID14,3.TheelectromagneticpropertiesofRFinpassivemicrowaveintegratedcircuits1521.Thisapproachisverypromisingbutstillinthedevelopingstage.Thequestionis:howisitpossibletoencodeinformationusingultralow-costpassiveRFdevices?Theprincipleoftheinformationencoding,whichconsistsinencoding