基于两种特殊结构的左手材料单元及其天线设计-电磁场与微波技术专业论文.docx

摘要3．针对左手材料在微带天线领域应用的问题，本文将主要设计的基于波浪结构的“申”字型左手材料分别加载到工作频点为WiMAX(3．5GHz)的微带天线的覆盖层、辐射贴片周边，以此探讨左手材料的加载对微带天线性能的影响。研究发现该左手材料制成天线覆盖层，当与接地板的间距在半个波长附近时，才能较好地改善天线的性能。并且在矩形贴片天线中的使用较三角贴片天线来说可改善天线性能且更稳定。而周边加载左手材料的影响与其分布有关，不过都能汇聚利用倏逝波，吸收表面波，使微带天线的性能得到改善。关键词：左手材料单元；双负特性；电磁谐振；微带天线万方数据AbstractAbstractWiththerapiddevelopmentofglobalinformationandtechnology．the requirementstowirelesscommunicationsystemsareincreasinglyhigh．Asanimportantpart，highergain．widerband，multi—bandandminiaturizationantennashavebecomeurgentlyneeded．Traditionalmicrostripantennasarelimitedinuseofthepracticalapplicationbecauseofbiglossandlowefficiency．However,theappearanceofartificialelectromagneticespeciallyleft—handedmaterialswithdoublenegativepropertiesopensanewwayforimprovingtheperformancesofantennas．Left_handedMaterials(LHMs)arepaidmoreandmoreattentioninthelaterresearchbecauseofitsspecialelectromagneticproperties．ThispaperfocusontheimplementationofLHMstructuresandhowtousethemonamicrostripantenna．Atfirst，basedonthecombinationoftheelectromagneticfieldtheoryandthecircuittheory,theimplementationofLHMstructuresistheoreticallyanalyzed．Onthisbasis，twoseriesofsingle-sideLHMunitsaredesignedbasedonawave．shapedandacucurbit—shapedstructuresrespectively．Anditiseasytottme．andwithwiderdoublenegativebandwidthandsmall size．Theninallusiontothe realrequirementofWiMAXmobilecommunication．twomicrostripantennasareproposedbyintroducingtheabovedesignedunitstructureasthecoverageorputtingonthesurroundingoftheradiationpatch．ThemainresearchworkoftNsarticleisdividedintoseveralpartsasfollows1．Aseriesofirregular．ringLHMbasedonawave—shapedstructureispresented，combinedwithanarclineandametalbarintoanumbrella—shapedleft-handedcellasamaintuningpart．Thisstructurecanproducearesonantfrequencyof6．60GHzanddoublenegativefrequencybandwidthof350MHz．Thentheresonantfrequencyisreducedto3．60GHzthroughthedetbrmationinarcstructure，byincreasingtheequivalentcapacitanceinitsequivalentcircuitmodel．Then．anewcurrentloopwitharesonantfrequencyneartheoriginaloneisaddedS