【作者】 叶春辉；

【导师】 李媛；

【作者基本信息】 天津大学 ， 电磁场与微波技术， 2008， 硕士

【摘要】 可重构天线技术是目前天线领域的研究热点。可重构天线可以在同一副天线上实现多副天线的功能,这一技术是为了满足近年来无线通信系统进一步向大容量、多功能、超宽带方向发展的需求而提出的。目前这一研究领域还处于发展阶段,仍然有许多难题需要解决。本文对可重构天线其中的一种形式――极化可重构天线做了初步的探索。在简要介绍了微带天线和极化的相关知识后,本文分析了无线通信系统尤其是MIMO系统采用圆极化天线的优势,随后,在归纳总结了近年来极化可重构天线研究成果的基础上,采用圆环缝隙结构设计极化可重构天线。首先通过理论分析和软件数值仿真,分析了圆环缝隙天线参数变化对其性能的影响,并通过仿真验证了文中提出的两种扩展天线带宽的方法,两种方法可将天线带宽提高将近4倍。然后根据圆极化形成的基本原理,改变圆环缝隙结构天线馈电网络,分别设计了右旋圆极化和左旋圆极化的天线。随后,基于右旋和左旋圆极化天线结构上的对称性,在天线上引入MEMS开关,设计了左右旋圆极化可重构天线。借助仿真软件,分析影响该天线性能的因素并在结构上加以改进和重新设计,得到性能上满足要求的天线结构。最后,将扩展带宽的方法应用到该天线上面,通过仿真和实测,证明该方法在不明显增加天线体积情况下,有效提高了天线带宽。更多还原

【Abstract】 The research on reconfigurable antenna technology is one of the hot spot in antenna field nowadays. The reconfigurable antenna can fulfill functions of multi-antenna on only on antenna, in order to increase the capabilities and functions of wireless integrated information systems and widen their bandwidths, overcome the drawbacks, the concept of reconfigurable antenna is presented. At present, this work is still at developing stage, and much unknown domains need to be overcome.In this paper, one kind of reconfigurable antenna--polarization reconfigurable antenna is analyzed preliminary, after brief introduction of microstrip antenna and polarization, advantages of adopting circular polarization antenna in wireless communication systems especially MIMO system is analyzed. Based on the summary of research results on polarization reconfigurable antenna of the world in recent years, ring slot structure is adopted to design polarization reconfigurable antenna.Through the theoretically analyze and numerical emulation, effect of parameters modification on ring slot structure antenna is analyzed. Two kinds of method which can widen antenna’s bandwidths for 4 times is presented and validated through emulation. Thereafter, based on the theory of circular polarization, through modifying feed network of antenna, clockwise and counter-clockwise circular polarization antenna are designed respectively.Based on the symmetrical of clockwise and counter-clockwise circular polarization antenna structure, MEMS switch are used on antenna, clockwise and counter-clockwise circular polarization reconfigurable antenna is designed. Resorted to emulator software, effects of parameters on antenna performance analyze and structure of antenna modified, then the structure satisfied request is obtained. At last, the method of widen antenna’s bandwidth is adopted, through emulation and measured, this method is proved to be availability.更多还原