双频与宽带圆极化天线研究

发布时间：2018-06-10 16:22

本文选题：双频段 + 宽频带　；参考：《西南交通大学》2014年硕士论文

【摘要】：天线作为无线电设备的关键部件,对通信系统的性能有着至关重要的影响。圆极化天线因为具有接收效率高及有效抑制雨雾干扰的特点,已在雷达、移动通信、电子干扰和卫星定位系统等领域中得到了广泛应用。本文通过结合相关科研项目,主要对圆极化天线的双频和宽带技术展开深入研究和探索,并在此基础上设计了一款双频圆极化微带贴片天线和两款宽带圆极化平面螺旋天线。文中首先介绍了近年来双频段和宽频带圆极化天线的研究现状,然后给出了微带天线的基本理论和实现双频、宽带圆极化的主要方法,接着分析了平面螺旋天线模型、工作原理和特性参数,最后是本文设计的三款圆极化天线,详细工作内容如下：设计了一款单馈电层叠式双频圆极化微带贴片天线,有效覆盖了北斗卫星导航系统(CNSS)的￡和S频段。天线采用层叠结构引入多谐振,并在贴片对角切角实现圆极化。通过引入空气层降低相对介电常数和在探针顶部加载容性金属片抵消了过长探针带来的感抗,实现了频段展宽。天线在数值仿真的基础上,获得较好的圆极化特性,结果表明,阻抗带宽在￡频段和S频段分别达到了82MHz和156MHz,3dB轴比带宽分别达到了18MHz和38MHz。本次设计不但实现了双频圆极化辐射,而且在每个频段的带宽都有所展宽,增加了天线在不同环境中使用的有效性与可靠性。最后完成了实物加工制作,并对回波损耗系数S11进行了测试与比较。设计了两款工作频率在1-12GHz的宽带圆极化平面螺旋天线。根据某项目要求,结合平面螺旋天线理论知识,首先对平面等角螺旋天线进行设计。为了实现平衡-非平衡间的转换以及天线输入阻抗与同轴线特性阻抗的变换,设计一种简单易加工的超宽带直线渐变型双面微带线巴伦。同时为了改善低频轴比,在螺旋臂末端加载吸收电阻,最终获得双向辐射的频比为12：1的宽带圆极化平面等角螺旋天线。鉴于项目对天线单向辐射的要求,后期进行了方案修改,设计了一款带有异形反射腔的阿基米德螺旋天线,并采用电性能更优的指数渐变结构微带巴伦对其馈电。最后利用电磁仿真软件进行分段仿真,对天线在每个频段的阻抗特性,主轴方向轴比特性,以及远场辐射方向图和增益等性能做出详细分析与讨论。结果表明,各项性能参数基本达到项目指标。
[Abstract]:As a key component of radio equipment, antenna plays an important role in the performance of communication system. Circular polarization antenna has been widely used in radar, mobile communication, electronic jamming and satellite positioning system due to its high receiving efficiency and effective suppression of rain and fog interference. In this paper, the dual-frequency and wideband technologies of circular polarization antenna are deeply studied and explored by combining with related scientific research projects. On this basis, a dual-frequency circularly polarized microstrip patch antenna and two wide-band circular polarized planar helical antennas are designed. Then the basic theory of microstrip antenna and the main methods to realize double frequency and wide band circular polarization are given. Then the planar helical antenna model, working principle and characteristic parameters are analyzed. Finally, three kinds of circular polarization antenna are designed in this paper. The detailed work is as follows: a single-fed stacked double-frequency circular polarized microstrip patch antenna is designed, which effectively covers the S band of Beidou Satellite Navigation system (CNSS). The antenna uses stacked structure to introduce multi-resonance and circular polarization is realized at diagonal tangent angle of the patch. By introducing air layer to reduce the relative dielectric constant and loading capacitive metal sheet at the top of the probe to cancel the inductance of the long probe, the band broadening is realized. On the basis of numerical simulation, the circular polarization characteristics of the antenna are obtained. The results show that the impedance bandwidth reaches 82MHz and 156MHz / 3dB axis ratio bandwidth in the frequency band and S band, respectively, and the impedance bandwidth reaches 18MHz and 38MHz respectively. This design not only realizes the dual-frequency circular polarization radiation, but also broadens the bandwidth of each frequency band, which increases the efficiency and reliability of the antenna in different environments. Finally, the material processing is finished, and the echo loss coefficient S11 is tested and compared. Two wide-band circularly polarized planar helical antennas operating at 1-12GHz are designed. According to the requirements of a project and the theoretical knowledge of planar helical antenna, the planar isobaric helical antenna is first designed. In order to realize the conversion between balance and non-equilibrium and the transformation between antenna input impedance and coaxial characteristic impedance, a simple and easy machining double sided microstrip line Barron is designed. At the same time, in order to improve the low frequency axial ratio, the absorption resistance is loaded at the end of the helical arm, and finally, the broadband circular polarization plane isobaric helical antenna with 12:1 frequency ratio of bidirectional radiation is obtained. In view of the requirements of the project for unidirectional radiation of the antenna, a modified scheme was carried out in the later period, and an Archimedes spiral antenna with a special-shaped reflecting cavity was designed, and the microstrip Barron with a better electrical performance was used to feed the antenna. Finally, the electromagnetic simulation software is used to simulate the impedance characteristics of the antenna in each frequency band, the characteristics of the spindle axis ratio, the far-field radiation pattern and the gain and so on. The results show that the performance parameters basically reach the project targets.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN821.1

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