超短波宽带小型化天线的研究-电磁场与微波技术专业毕业论文.docx

摘 要
随着通信系统要求的越来越高,以及电子设备微型趋势的发展,作为通信终端的天线也必然向小型化和宽带化发展,因此,本论文研究的主要工作就是天线的小型化和宽带化设计。
论文首先总结了国内外现存的对天线宽带化和小型化设计的方法,基于文中所设计天线的基础是偶极子,所以对偶极子的基本原理进行了介绍。最后,针对宽带化和小型化要求分别设计了三种天线。
第一种是工作在 800-960MHz 的平板天线,该天线的设计是为了满足实验室项目的要求。在此基础上,在天线的反射板上运用周期结构,使天线的带宽扩展到 760-1220MHz,大大提高了带宽,实现了宽带化的目的。第二种天线是工作在
500MHz 的密距八木天线,通过使用 T 形匹配天线来取代传统八木天线中的半波对称振子,使得天线在其他电气特性满足要求的情况下,纵向尺寸相比传统八木缩小
了七到八倍,实现了小型化的目的。第三种天线是工作在 15MHz 的交叉场天线 CFA, 它具有非常小的尺寸,仅有 1/40 个波长的高度,但带宽与传统电小天线相似,相对带宽大约 5%,通过在天线上增加套筒,一定程度地拓展了带宽,相对带宽提高到了 10%。对 CFA 的进一步研究,以完善其理论是下一步的工作重点。
关键词:小型化;宽带化;平板天线;八木天线;交叉场天线
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Abstract
The miniature and broadband antenna which works as terminal munication system is inevitably as the higher requirement munication system and the development of Electronic equipment. So, the main task of this thesis is to design the miniature or broadband antennas.
Firstly, the methods of design the miniature and broadband antennas are summarized. The basic theoretical of dipole is introduced, because dipole is the foundation of the antennas designed in this thesis. Finally, three miniature or broadband antennas are proposed.
The first is flat antenna which bandwidth covering 800- antenna is designed to meet the requirement of the project. On this basis, periodic structure is used on the baffle of the antenna to expand the antenna’s bandwidth. The new flat antenna’s bandwidth covers 760-1220MHz. It achieves the purpose of broadband. The second pact yagi antenna which works at vertical dimension of the antenna is about 1/7 of the traditional yagi antenna by using T-match antenna displace dipole. It achieves the purpose of miniaturization. The third is Crossed-Field-Antenna (CFA). Its size is only 1/40 of the wavelength while its bandwidth is almost the same of traditional electrically small antennas. The relative bandwidth is promoted from 5% to 10% by adding a sleeve outside of the antenna. The next key emphasis in work is consummate CFA’s theory.
Key words: miniaturization; broad