【作者】 李清栋；

【导师】 冯全源；

【作者基本信息】 西南交通大学 ， 通信与信息系统， 2012， 硕士

【摘要】 信息传输是人类社会生活的重要内容,人们的生活已经和通信技术融为一体。而通信技术的迅猛发展和广泛应用,也极大地推动了社会的发展,并给人们的生活方式带来了深刻的变革。无线通信是通信系统中应用最为广泛的一种方式,它在不使用明线的前提下实现先远距离快速通信的目的,在现代通信领域中占有越来越重要的地位。在无线通信系统中,天线的作用无可替代,天线是无线电波的出口和入口,即完成通信系统的发射和接受功能。一切无线电通信、广播、雷达、导航等工程系统都是利用无线电波来进行工作的,缺少出入接口的系统不可能正常完成任何功能。没有天线,就不可能建立起任何无线通信的联系。微带天线是天线的重要实现形式之一,具有低剖面、重量轻、易共形、易制作、低成本以及易与电路集成等优点,在无线通信领域有着广泛的应用。在本文中对微带天线设计的现状进行了总结,并在此基础上对微带天线的小型化、宽带化、可调节技术进行了广泛调研,结合全波分析软件对天线进行了建模分析,针对天线模型的阻抗匹配、增益等问题进行优化。本文的第一个主要内容是研究了微带天线的小型化和宽带化的问题,基于微带天线小型化常见的实现形式-平面倒F天线,对其小型化和频带展宽的问题进行了研究。通过地板开槽和辐射贴片开槽的方式使得天线的相对工作频带得到了有效提升,增幅超过了50%,通过特殊介质的加载使得天线的体积得到了更有效的减小。在此研究的基础上做了更进一步的探究,通过增加中间辐射贴片的方式使得天线的谐振频率下降到了VHF频段,使天线的尺寸仅为传统平面倒F天线的28%,并且该天线在270MHZ的中心频带内的阻抗带宽超过了30%。本文的另一个主要内容是对天线的频率可调节技术进行了研究,重点探讨了新型人工电磁媒质-超材料在频率可调节天线中的应用。针对现存设计中存在的天线的尺寸过大、工作频率连续可调实现困难等缺点,本文基于复合左／右手传输线理论,通过加载变容二极管的方式来实现天线工作频率的实时可调节。设计出的天线尺寸仅有15mm*15mm*0.8mm,仿真结果表明其工作频率可在S波段超过700MHz的频率范围内可调(S11优于-10dB),其增益等相关性能参数满足应用需要。该天线具有结构简单、体积小等优点,具有一定的理论意义和广阔的应用前景。更多还原

【Abstract】 Information transmission is an important part in human society, especially, in the modern society, the widely use of phone or mobile-phone smakes people communicating anytime and anywhere, People’s lives have been integrated with the communication technologies together. The rapid development and wide application of communication technologies, have greatly promoted the development of society, and have brought profound changes to the style of people’s life. The wireless communication is most widely used in the communication system, not depend on the visual transmission medium, wireless communication realized the purpose of rapid communication. Therefore it plays an increasingly important position in the modern communications. In numerous constituent components of the communication system, antenna plays an irreplaceable role. Antenna is the entrance and exit of the radio waves in wireless communication system, used to complete the transmitting and receiving functions. All radio communication, radio, radar, navigation and engineering systems use radio waves to carry out the work, the lack of access interface will lead to the system can not complete any functionsMicrostrip antenna is one of the most important manifestations of antenna, which has been widely used in Wireless communications system during the recent decade because its outstanding properties of low profile, low cost, light weight, easily fabricated and easily integrated with radio frequency and microwave circuit. This thesis presents a summary of the status of the microstrip antenna design. Based on this work, a widely range of research job was done on the technology of microstrip antenna miniaturization, broadband and frequency tunable. Combining with the full-wave analysis software, an optimization work was done for the model, impedance matching, gain of the antenna.The first major content of this thesis is to study the miniature and band exhibition problem of the Planar Inverted F Antenna. Ground plane and radiation patch slotted operation makes the antenna relative frequency band raised from21.9%to36.9%, an increase of68.5%was achieved, and special media loaded makes the size of the antenna reduce more effectively. Further exploration was done based on the previous work. The loaded of middle patch makes the resonant frequency decreased to the VHF band, which made the relative size of antenna decreased to28%of traditional Planar Inverted F Antenna, and the Impedance bandwidth over270MHZ can be larger than30%. Another main content of this thesis is the research of frequency tunable technology, especially the application of artificial electromagnetic media in antenna frequency tunable field. Based on the theory of Composite Right/Left Handed Transmission Line (CRLH TL), Varactor diode is loaded to realize the resonant frequency real-time tuned. The volume of the antenna is only15mm*15rnm*0.8mm, simulation results show that the resonant frequency can be tuned more than700MHz in S-band (S11parameter is better than-lOdB). The antenna has a simple structure, compact size, which has some theoretical significance and is attractive for applications in microwave system.更多还原