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1、ANALYSISOFATMOSPHERICEFFECTSDUETOATMOSPHERICOXYGENONAWIDEBANDDIGITALSIGNALINTHE60GHZBANDByAdeliaC.ValdezThesissubmittedtotheFacultyoftheVirginiaPolytechnicInstituteandStateUniversity(VirginiaTech)inpartialfulfillmentoftherequirementsforthedegreeofMasterofScienc
2、eInElectricalEngineeringDr.TimothyPratt,ChairDr.CharlesBostianDr.DennisSweeneyJuly2001Blacksburg,VAKeywords:60GHz,WidebandSignals,atmosphericabsorption,oxygenresonanceCopyright2001,AdeliaC.ValdezANANALYSISOFATMOSPHERICEFFECTSDUETOATMOSPHERICOXYGENONAWIDEBANDDIG
3、ITALSIGNALINTHE60GHZBANDAdeliaC.ValdezAbstractAslowermicrowavefrequencybandsbecomesaturatedwithusers,thereisamotivationfortheresearchofapplicationsthatutilizehigherfrequencies,especiallythe60GHzband.Thisbandisplaguedwithhighatmosphericabsorptionduetoatmospheric
4、oxygen,buthasalotofbandwidth,whichmakesitdesirableformulti-mediaapplications.Recently,researchofwidebanddigitallinkswithinthe60GHzbandgainedtheinterestofthewirelesscommunicationindustrywhentheFCCannouncedthatalicenseisnotrequiredforawidebanddigitalsignalinthisb
5、and.Previousresearchon60GHzsignalsfocusedonhowmuchattenuationduetoatmosphericoxygenexistsinthelink.Butalookatthephysicalpropertiesofatmosphericoxygenrevealsboththereasonwhyatmosphericoxygenabsorbselectromagneticwavesandhowpressureaffectsatmosphericoxygen.Atmosp
6、hericoxygenresonatesat60GHzduetotransitionsbetweenitsthreecloselyspacedrotationalstates.Thesetransitions,combinedwiththemagneticdipolemomentofatmosphericoxygen,causeattenuationandphasedispersioninelectromagneticwaves.Atlowerpressures,theindividualresonancelines
7、ofatmosphericoxygenappearintheattenuationandthephasedispersionplots.Aspressureincreases,theresonancelinesbroadenandcontributetoneighboringresonantlines.Theeffectofattenuationandphasedispersioninawidebandsignalbecomesgreateratloweratmosphericpressures,whichresul
8、tsinsignaldistortion.Thesignaldistortionleadstomorebiterrorsandresultsinthepresenceofinter-symbolinterference(ISI)inthereceivedsignal.Thisthesisaimstoanalyzetheeffectsofatmo