2.4G高增益天线毕业论文英文翻译--天线的性能

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1、学位论文中北大学分校学位论文英文翻译作者姓名：李雁鹏学科、专业：通信工程学号：062027指导教师：王章勉副教授完成日期：2010-6-10中北大学分校中北大学分校学位论文英文翻译目录PROPERTIESOFANTENNAS21.1ANTENNARADIATION31.2GAIN51.3EFFECTIVEAREA81.4PATHLOSS81.5RADARRANGEEQUATIONANDCROSSSECTION101.6WHYUSEANANTENNA?12天线的性能121.1天线辐射131.2增益151.3有效面积171.4路径损耗181.5雷达距离方程和截面201.6为什么要使用一

2、个天线？2121中北大学分校学位论文英文翻译英文原文：PROPERTIESOFANTENNASOneapproachtoanantennabookstartswithadiscussionofhowantennasradiate.BeginningwithMaxwell’sequations,wederiveelectromagneticwaves.Afterthatlengthydiscussion,whichcontainsalotofmathematics,wediscusshowthesewavesexcitecurrentsonconductors.Thesecondha

3、lfofthestoryisthatcurrentsradiateandproduceelectromagneticwaves.Youmayalreadyhavestudiedthatsubject,orifyouwishtofurtheryourbackground,consultbooksonelectromagnetics.Thestudyofelectromagneticsgivesinsightintothemathematicsdescribingantennaradiationandprovidestherigortopreventmistakes.Weskipthe

4、discussionofthoseequationsandmovedirectlytopracticalaspects.Itisimportanttorealizethatantennasradiatefromcurrents.Designconsistsofcontrollingcurrentstoproducethedesiredradiationdistribution,calleditspattern.Inmanysituationstheproblemishowtopreventradiationfromcurrents,suchasincircuits.Whenever

5、acurrentbecomesseparatedindistancefromitsreturncurrent,itradiates.Simplystated,wedesigntokeepthetwocurrentsclosetogether,toreduceradiation.Somediscussionswillignorethecurrentdistributionandinstead,considerderivedquantities,suchasfieldsinanapertureormagneticcurrentsinaslotoraroundtheedgesofamic

6、rostrippatch.Youwilldiscoverthatweuseanyconceptthatprovidesinsightorsimplifiesthemathematics.Anantennaconvertsboundcircuitfieldsintopropagatingelectromagneticwavesand,byreciprocity,collectspowerfrompassingelectromagneticwaves.Maxwell’sequationspredictthatanytime-varyingelectricormagneticfieldp

7、roducestheoppositefieldandformsanelectromagneticwave.Thewavehasitstwofieldsorientedorthogonally,anditpropagatesinthedirectionnormaltotheplanedefinedbytheperpendicularelectricandmagneticfields.Theelectricfield,themagneticfield,andthedire