超短波宽带螺旋加载天线研究

【作者】 王巍；

【导师】 阮成礼；

【作者基本信息】 电子科技大学 ， 无线电物理， 2006， 硕士

【摘要】 本论文系统的研究了天线的小型化技术和宽频带特性，且重点针对全向宽带超短波(VHF)天线进行了理论分析和实验研究，并提出了两种与主题相关的设计方案，注重面向工程应用。 对于全向宽带VHF天线，要在降低天线高度的同时，保持天线较高的增益，其核心思路就是在有限的空间内尽量增加天线的电长度，但是在给定高度内增加电长度却是以牺牲带宽为代价的。为了同时保证天线的宽带特性，多种频带展宽技术被应用。作者利用矩量法(MoM)和有限积分技术(FIT)成功地完成了对宽带超短波螺旋天线的设计和仿真，创造性工作主要体现在： 1、在天线尺寸受到限制的条件下，运用螺旋结构和平面弯折结构增加天线电长度，有效的降低了天线高度。 2、结合粗振子天线和平面天线的宽带馈电结构，运用螺旋天线和平面弯折天线与其相耦合的方法，实现宽带电小特性。 3、通过介质加载，进一步降低了天线高度，同时起到天线罩的作用。 4、运用遗传算法等优化技术对天线的宽带匹配网络进行设计，使天线系统在30～88MHz全频段内实现了驻波要求。 结合以上方法，本文创造性的提出了超短波宽带螺旋加载单极子天线和超短波平面螺旋加载天线等设计方案，在30～88MHz内实现了天线高度低于1.2m，驻波小于3，增益大于2的超短波全向天线。并且对相应的缩比模型进行了加工实验，效果很好。更多还原

【Abstract】 The dissertation is mainly on the topics of miniaturization technology and broadband characteristics for antennas, and that mainly researched omni-direction broadband antennas in very high frequency (VHF) with a lot of theoretical and experimental studies. Several design schemes related to the topics are introduced and many attentions are paid to the engineering application.The omni-direction broadband antennas in VHF are not only requested to have a. compact structure but also a given gain. To meet these requests about the electric and structure’s parameters of engineering a central thought way is make the most of a limited space to increase the electric length of the antenna. But the bandwidth will be reduced because of increasing of the electric length in the limited space. To satisfied gain as well as bandwidth a series of design of miniaturization and broadband are studied. In this thesis, MOM and FIT are used to design and simulate the broadband helix antenna in VHF. The author’s major contributions are as follows:1. A helix or planar bend structure is used to increase the electric length of antenna when the dimension is limited. The height of antenna is reduced effectively.2. Thick monopole and planar antennas have broadband characteristic relatively. When they are fed and coupled with a helix or planar bend structure it will be realized a rather broad bandwidth and electric small performance.3. Dielectric loaded antenna can reduce the height of antenna and the dielectric can also act as a radome simultaneously.4. A broadband matching network are designed and optimized by the genetic algorithm (GA) to realize a VSWR claim over 30-88MHz.To make use of above these ways a broadband monopole with a parasitic helix and a broadband planar antenna with a parasitic planar helix in VHF are designed successfully, and they can realize VSWR<3, Gain>2 and the height <1.2m over 30-88MHz.更多还原