GSMR频段微带带通滤波器的研究与设计

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1、北京交通大学硕士学位论文GSM-R频段微带带通滤波器的研究与设计姓名：张晓燕申请学位级别：硕士专业：通信与信息系统指导教师：周克生20080601关键词：GSM—R频段；微带带通滤波器；准椭圆函数；耦合系数矩阵；小型化；交指电容加载谐振器分类号：j匕塞交通太堂亟±堂垡j金塞一△曼墨!B△￡至ABSTRACTFiltersplayveryimportantrolesinmanyRF／microwaveapplications．Emergingapplicationssuchaswirelesscommunicationscontinuetochal

2、lengeRF／microwavefilterswithevermorestringentrequirements--higherperformance，smallersize,lighterweightandlowercost．·Thispaperpresentsthedesignofaclassofmiorostripbandpassquasi—ellipticfunctionfilterswimthebandwidthof4MHzandthefractionalbandwidth

3、attenuationpolesatfinitefrequencies．Becauseoftheseattenuationpolesatfinitefrequencies，quasi—ellipticfunctionfiltersperformancehigherselectivityandsharperfilterskirtthanChebyshevones．Thistypeoffilters，whichconsistofthecrosscouplingmicrostripopen-loopresonators，Cannotonlyreduce

4、thedifficultyoffabrication，butalsoresultinacompacttopology．Thelocationsoftwofmitcfrequencyattenuationpolesofthequasi·ellipticfunctionbandpaSSfiltersareat883．4MHzand890．6MHzwhosecenterfrequencyis887MHzorat928．4MHzand935．6MHzwhosecenterfrequencyis932MHz．Theseplanarstructuresofm

5、iorostripban@a8squasi—ellipticfunctionfiltershavebeenstudiedanddesignedinthispaperonaccountofthereasonabove．However,theexistingnarrow-bandmicrostripfiltersforfractionalbandwidth<1％aredifficulttofabricatedonconventionalsubstrates，becausemiorostripcannotevenformacompletepassban

6、d．Inthispaper,thefilterisrealizedusingtheconfigurationbased011thefull-waveEMandfabricatedusingacoppermicrostripOilansubstrate、加marelativedielectricconstantof10．8andathicknessof1．27mm．Onthebasisofthefiltersabove,akindofslow-wavefiltersconsistofcapacitiveloadedopen-loopresonato

7、rsaredesigned．Thenovelfilterisnotonlymorecompactinsizebutalsohavewiderstop—band．Atlast,thepefformancesofthesefiltersaremeasuredbyHP8270Dvectornetworkanalyzer．Themeasuredresultsshowthatthiskindofmiorostripban@assfiltersarecharacterizedhighlyselectiveandnarrowbandwidthwithasing

8、lepairofattenuationpolesatfmitcfrequencies．Butinsertlossofthefabrica