通信工程专业 外文文献翻译 优秀毕业设计（论文）

ANOVELMETHODFORDESIGNINGDUALFREQUENCYSLOTPATCHANTENNASWITHTWOPOLARIZATIONSWUDI1,OHISHIBASHIHIDEKAZU2,SEOKAZUYUKI2,INAGAKINAOKI31DEPARTMENTOFCOMMUNICATIONENGINEERING,SHANGHAIUNIVERSITY,SHANGHAI200072,CHINA2KOJIMAR3NAGOYAINSTITUTEOFTECHNOLOGY,NAGOYA4668555,JAPANABSTRACTTHISPAPERPRESENTSANEWMETHODFORDESIGNINGADUALFREQUENCYPATCHANTENNAWITHCIRCULARANDLINEARPOLARIZATIONSDUALFREQUENCYOPERATIONSAREBEHAVEDBYETCHINGTWONARROWSLOTSCLOSETOTHERADIATINGEDGESOFARECTANGULARPATCHTHECIRCULARPOLARIZATIONATTHELOWERRESONANTFREQUENCYOFTHEDUALFREQUENCYANTENNACANBEACHIEVEDBYSETTINGAPERTURBATIONSEGMENTATANAPPROPRIATELOCATIONINTHEPATCHELEMENT,ANDPLACINGTHEFEEDPOINTONTHEDIAGONALAXISSEVERALEXPERIMENTALRESULTSOFADESIGNEDANTENNASHOWTHEGOODCHARACTERISTICSFORCIRCULARANDLINEARPOLARIZATIONSATBOTHRESONANTFREQUENCIESCLCNUMBERTN8211DOCUMENTCODEAKEYWORDSDUALFREQUENCYSLOTPATCHANTENNASLINEARPOLARIZATIONCIRCULARPOLARIZATIONINRADARANDCOMMUNICATIONSYSTEMS,DUALFREQUENCYOPERATIONSAREOFTENREQUIREDSPECIALLY,INMODERNMOBILEGLOBALPOSITIONSYSTEMGPS,ITWILLBEDESIRABLETHATONEOFTWOFREQUENCIESISTHECIRCULARPOLARIZATIONPLANARANTENNAHASBEENINVESTIGATEDFORMULTIFREQUENCYVERYWELLSINCEITISADVANTAGEOUSINLOWCOST,LOWWEIGHTANDCONFORMABILITYEARLYDUALFREQUENCYPLANARANTENNAISMULTILAYEREDSTACKEDPATCHSTRUCTURE,ANDTHERADIATINGELEMENTISUSEDTOBECIRCULAR1,ANNULAR2,RECTANGULAR3ANDTRIANGULARPATCHES4RECENTLY,ADUALFREQUENCYANTENNAISINTRODUCEDINWHICHTHESTRUCTUREISDINGLELAYERPATCHWITHTWOSLOTSCLOSETOTHERADIATINGEDGES,ANDGOODPERFORMANCESOFSIMULTANEOUSIMPEDANCEMATCHINGANDGAINAREDEMONSTRATEDFORBOTHRESONANTFREQUENCIESHOWEVER,ALLTHECONVENTIONALINVESTIGATIONSAREONLYFORTHECASEINWHICHTHEANTENNAPOLARIZATIONISLINEAR,WHILETHEDUALFREQUENCYANTENNAWITHCIRCULARPOLARIZATIONHASNOTBEENTOUCHEDYETINTHISPAPER,WEPRESENTADESIGNMETHODOFADUALFREQUENCYANTENNAWITHCIRCULARANDLINEARPOLARIZATIONSBASEDONTHECONVENTIONALINVESTIGATIONFORTHEDUALFREQUENCYLINEARPOLARIZATIONANTENNA57,TWORESONANTFREQUENCIESAREDETERMINEDBYADJUSTINGTHESIZEOFTHEPATCHELEMENTANDTHESLOT,ASWELLASTHELOCATIONOFTHESLOTINTHEELEMENTTHEKEYTOOBTAINACIRCULARPOLARIZATIONFORANANTENNAISTOSATISFYTHECONDITIONFOREXCITINGCIRCULARPOLARIZATION,IE，THECIRCULARPOLARIZATIONCANBEEXCITEDBYSETTINGTHEPERTURBATIONSEGMENT,ATANAPPROPRIATELOCATIONINTHEPATCHELEMENT,ANDBYPLACINGTHEFEEDPOINTONTHEDIAGONALAXISWEHAVEEXPERIMENTALLYOBTAINEDTHECIRCULARANDTHELINEARPOLARIZATIONSATBOTHLOWERANDUPPERFREQUENCIES,ANDSOMEEXPERIMENTALRESULTSWILLBEDEMONSTRATEDONTHEREFLECTIONLOSSATINPUTPORTANDTHERADIATIONPATTERNOFTHEANTENNA1CONFIGURATIONOFCONVENTIONALDUALFREQUENCYPATCHANTENNAFIGURE1SHOWSACONFIGURATIONOFACONVENTIONALDUALFREQUENCYANTENNAWITHLINEARPOLARIZATIONTWORESONANTFREQUENCIESAREBEHAVEDBYETCHINGTWOSLOTSCLOSEANDPARALLELTOTHERADIATINGEDGES,ANDTHELOWERRESONANTFREQUENCYISDETERMINEDBYTHEOUTLINESIZEOFTHEPATCHELEMENT,WHILETHEUPPERRESONANTFREQUENCYISDETERMINEDBYTHESIZEANDTHEPOSITIONOFTHETWOSLOTSINTHEPATCHELEMENTBECAUSETHESLOTSARECLOSELYLOCATEDTOTHERADIATINGEDGES,AMINORPERTURBATIONOFTHETM10MODECANBEEXPECTEDASFORUNPERTURBEDTM30MODE,SINCETHESLOTSARELOCATEDWHERETHECURRENTSHALLBESIGNIFICANT,THECURRENTWILLBESTRONGLYMODIFIED,ANDAPERTURBEDTM30RADIATIONPATTERNSIMILARTOTHETM10MODECANBEOBTAINEDOUROBJECTINTHISINVESTIGATIONISTOOBTAINADUALFREQUENCYANTENNAWITHBOTHPOLARIZATIONINWHICHTHELOWERFREQUENCYISWITHACIRCULARPOLARIZATIONANDTHEUPPERFREQUENCYISWITHALINEARPOLARIZATIONFORASQUAREPATCHANTENNAWITHLENGTHOFTWOPARALLELSUBTENDSOFTHEPATCHELEMENTINORDERTOSETAPERTURBATIONSEGMENTAREAOFSFEDBYONEPORT,AWAYTOEXCITEACIRCULARPOLARIZATIONISTOEXTENDTHES,ANDPLACETHEFEEDINGPOINTONTHEDIAGONALAXISWHENANAPPROPRIATEPERTURBATIONISSELECTED,ACIRCULARPOLARIZATIONWITHAGOODAXIALRATIOCANBEOBTAINEDFIG1CONFIGURATIONOFCONVENTIONALDUALFREQUENCYANTENNA2DESIGNINGFORDUALFREQUENCYSLOTPATCHANTENNASWITHTWOPOLARIZATIONSINACONVENTIONALINVESTIGATIONFORDUALFREQUENCYWITHLINEARPOLARIZATION57,TOENSUREAGOODRADIATIONEFFICIENCYATBOTHFREQUENCIES,THEASPECTRATIOBETWEENTHETWOSIDESOFTHEPATCHISTAKENINTHERANGE1078LWANDTHELOWERFREQUENCYISDETERMINEDBY2“2/,LRRCFLTWHERECISTHEVELOCITYOFLIGHTINFREESPACE，ISTHEEFFECTIVEPERMITTIVITYGIVENBYR31210,2RYXXAND41504WLWL5“,RGTHERE610361,28074LN25185XYGYXANDTHEUPPERFREQUENCYISDETERMINEDBY72/,HRRCFLLDWTINABOVEEXPRESSION,THEPARAMETERSOFW,L,T,W,D,LAREREFERREDTOFIG2,ANDTHEISTHEDIELECTRICCONSTANTOFTHESUBSTRATEHOWEVER,INTHISSTUDY,INORDERTOOBTAINRACIRCULARPOLARIZATIONATTHELOWERRESONANTFREQUENCY,THEASPECTRATIOOFTHEOUTLINESIZEOFTHEPATCHWILLBECHANGEDSOTHATTHEMENTIONEDFORMULASABOVEWILLNOTBECOMPLETELYSATISFIEDFIG2CONFIGURATIONOFDUALFREQUENCYWEPRESENTADESIGNMETHODFORDUALFREQUENCYSLOTPATCHANTENNAWITHTWOPOLARIZATIONASFOLLOWSSTEP1DESIGNASQUAREPATCHANTENNAWITHTHEDESIRABLELOWERFREQUENCYF10BYUSINGACONVENTIONALMETHODSTEP2ETCHTWOSLOTSCLOSEANDPARALLELTOTHERADIATINGTOBEHAVETHEDUALFREQUENCIESOPERATIONBYUSINGEQ7HOWEVERTHELOWERRESONANTFREQUENCYF10WILLCHANGE,SINCETHESLOTSMODIFYTHECURRENTDISTRIBUTIONOFTHETM10STEP3ADJUSTTHESIZEOFTHEANTENNAELEMENTTOOBTAINTHEDESIREDLOWERRESONANTFREQUENCYSTEP4ADJUSTTHELENGTHANDTHEWIDTHOFTHESLOTSTOOBTAINTHEUPPERRESONANTFREQUENCYF30STEP5SETPERT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化，贴片轮廓的纵横比将会改变，因此，上述公式将不会完全得到满足。图2双频天线的结构我们提出了一种双频开槽双极化天线的设计方法，如下所述第一步用传统方法设计符合要求的低频的方形贴片天线。第二步应用方程（7），刻蚀两个与辐射边缘很近的平行槽来实现双频工作。然而，由于两槽改变了TM10的电流分布，较低的谐振频率F10将会改变。第三步校正天线单元的大小来获得所想要的低频。第四步校正两槽的长宽来获得较高的谐振频率F30。第五步设置天线的摄动单元和馈点来获得在低谐振频率下的圆极化。3实验结果与讨论我们用实验的方法设计了一个双频双极化贴片天线。图2展示了天线的结构，天线的详细说明如表1所示。在这个天线结构中，我们延长贴片天线的L边来来调节摄动元素，而将馈点设置在对角线上以便获得圆极化特性。表1具有双极化的双皮贴片天线的详细说明GPSVICSFREQUENCY/GHZ157525POLARIZATIONCIRCULARLINEARRETURNLOSS1515GAIN3DB5DB图3显示了测量到的所设计双频天线的反射损失，天线是由50同轴电缆反馈的。由这幅图可见，两个谐振频率均在所需的1575GHZ和250GHZ两个频点附近，这两个频率将被应用于GPS和VICS，并同时实现了较好的阻抗匹配在1575GHZ附近的反射损失值为17DB，在25GHZ附近的反射损失值为27DB。图3反射损失的频率特征图4显示了这个天线的轴比随频率变化而变化的关系。可以看出在1575GHZ时的最佳轴比为1DB。图4轴比的频率特性与图3相比，图5显示了测量到的天线阻抗特性。这说明在低频1575GHZ出为实现圆极化而留有摄动余量。图5输入阻抗的频率特性图6显示了在较低谐振频率1575GHZ上设计的圆极化天线的辐射图。图中，我们使用单位DBIC来表示增益大小