圆形微带天线毕设论文

大连海事大学毕业论文二○一三年六月┊┊┊┊┊┊┊装┊┊┊┊┊┊┊订┊┊┊┊┊┊┊线┊┊┊┊┊┊┊圆形微带天线的仿真设计专业班级：通信工程1班姓名：徐睿指导教师：王钟葆信息科学技术学院I摘要微带天线以其体积小、重量轻且容易实现多频段的特点，越来越得到广泛应用，但其带宽较窄，限制了其发展，因此展宽微带天线的带宽具有十分重要的意义。为了拓宽阻抗带宽，本文通过HFSS仿真软件，对圆形微带天线进行建模研究。天线采用聚四氟乙烯和空气两层介质，通过同轴探针顶部加载圆形金属电容片来对辐射贴片进行耦合馈电，由此补偿探针引起的电感，调整圆形贴片尺寸、金属电容片尺寸和馈电点位置，来达到谐振点。并且分析了不同厚度空气层介质对微带天线带宽的影响，分析其规律，最终使天线带宽达到最大。本文中建模仿真的工作频率为2.45GHz，分析结果表明最终得到带宽达到24%，远超过一般微带天线的2%-5%。关键字：宽频带；圆形微带天线；电容馈电IIABSTRACTMicrostripantennaisgettingwidelyusedbecauseofthecharacteristicsofsmallvolume,lightweight,andeasilyachievingmulti-bandoperation.Butthenarrowbandwidthtotallylimiteditsdevelopment,improvingthebandwidthofthemicrostripantennahasmuchvitalsignificance.Inordertobroadentheimpedancebandwidth,astudyonthecircularmicrostripantennabasedontheHFSSsimulationsoftwareisperformedinthispaper.Theantennaconsistsoftwolayermedium,whicharethePTFEandtheair,feedingtheradiationpatchbyaddingacircularmetalcapactivepatchtothetopofcoaxialprobe,sothiscouldcancelouttheinductancecausedbyprobe.Byadjustingthesizeoftheradiationpatchandcapacitivepatch,andthepositionofthefeedpoint,theresonancepointcanbeachieved.Theanalysisoftheeffectofdifferentthicknessoftheairlayeronthebandwidthofmicrostripantennaisperformedtofindthemaximumbandwidth.Theoperationfrequencyofthedesignedantennainthispaperis2.45GHz,theresultsshowthatthebandwidthof24%,farmorethan5%ofthetraditionalmicrostripantenna.Keywords：Broadband;Circularmicrostripantenna;CapactivefedIII目录第1章绪论....................................................................................................................................11.1概述....................................................................................................................................11.1.1国内外研究动态......................................................................................................21.1.2.研究目的和意义......................................................................................................21.2本章小结............................................................................................................................2第2章微带天线的基本理论.........................................................................................................32.1概述....................................................................................................................................32.2微带天线的分析方法........................................................................................................32.2.1传输线法.................................................................................................................42.2.2空腔模型.................................................................................................................52.2.3其它方法.................................................................................................................62.3微带天线的馈电方法........................................................................................................62.3.1微带线馈电.............................................................................................................62.3.2同轴线馈电.............................................................................................................62.3.3电磁耦合馈电.........................................................................................................72.4微带天线频带展宽的方法.................................................................................................72.4.1采用厚基板..............................................................................................................72.4.2采用相对介电常数较小或损耗角正切较大的基板..............................................72.4.3附加阻抗匹配网络..................................................................................................82.4.4采用楔形或阶梯形签板..........................................................................................82.4.5采用非线性基板材料..............................................................................................82.4.6采用非线性调整元件..............................................................................................82.4.7采用在贴片或接地板“开窗”的办法................................................................92.5空气介质对天线影响.........................................................................................................92.6本章小结............................................................................................................................9第3章软件模型构建...................................................................................................................113.1HFSS简介........................................................................................................................113.2模型建立...........................................................................................................................113.2.1分步建模................................................................................................................113.2.2模型效果图............................................................................................................133.3分析设置