宽带带通滤波器分析

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1、ABSTRACTABSTRACTAlongwiththerapiddevelopmentofmultimediatechnology,wirelesscommunicationtechnologyhasbeendevelopedfromsoletransmissionoforiginaltext,voicetohigh-ratetransmissionofvideoandevenlargerfiles.Traditionalnarrowbandcommunicationtechnologiesareunabl

2、etomeetrequirementofhighspeed,largedatatransmission,sothereisanurgentmotivationtodevelopwide-bandcommunicationtechnologies.SincetheFederalCommunicationsCommittee(FCC)authorizedtheunlicenseduseoftheultra-wideband(UWB)frequencyspectrumforindoorandhand-heldwir

3、elesscommunicationsin2002,UWBtechnologyimmediatelybecameoneofresearchhotspotsinthefieldofwirelesscommunications.AsoneoftheessentialcomponentsinUWBcommunicationsystem,UWBfilterplaysasignificantroleindecidingtheoverallperformanceofthesystem.Unfortunately,ther

4、eexistsomanywirelessnarrowbandapplicationswhosesignalwillinterferewithUWBcommunication.Thus,UWBfilterswithmultiplenotchedbandsareproposedtoeliminatethosenarrowbandinterferances.Inthisthesis,someUWBfilterswithsingleanddualnotchbandsareproposedanddiscussed.Th

5、emainworkispresentedasfollows:1.Compactmicrostripultra-wideband(UWB)bandpassfilterswithmultiplesuperposablenotchedbandsarediscussed.BycascadingnT-Shapedstructurestoathreecoupled-linesection,UWBbandpassfrequencyresponsewithnnotchedbandscanbeobtained.Theanaly

6、sisshowsthatthesenotchedbandsaresuperposableandcanberelativelyindependentlyadjustedinwidefrequencyrange.TwoUWBfilterswithnotchedbandsaredesigned,fabricatedandmeasured.Themeasuredresultsshowthattwofiltersarefeaturedbygoodperformanceandcompactsize.2.Anovelcom

7、pactUWBfilterwithnarrownotchedbandispresentedbydirectlycascadingapairofshortedstubstoparallelcross-couplinglines.Thefrequencypositionsofthenotchedbandscanbeshiftedfrom4.2GHzto9.2GHzbytuningthedimensionoftheshortedstubs.Themeasuredresultsshowthatthefilterhas

8、themeritsoflowinsertionlosse,sharprejectionandflatgroupdelay.Thebandwidthofthenotchedbandisabout100MHz,andtheperformanceinandoutofthepassbandisgood.Moreover,thefilterexhibitstheadvantagesofsimpletopolo