多偶极子天线研究及其应用

发布时间：2018-02-15 11:01

本文关键词： 基站天线圆极化天线多输入多输出(MIMO)天线八木天线稳定的辐射方向图交叉极化比宽轴比波瓣宽度定向天线阶梯型反射器　出处：《华南理工大学》2015年博士论文　论文类型：学位论文

【摘要】：随着移动通信4G时代的到来以及向5G时代的迈进,多偶极子天线在移动通信系统中的作用会越来越重要。通过控制多个偶极子上电流幅度、相位以及空间位置之间的关系,多偶极子天线可以广泛应用于基站天线、圆极化天线、多输入多输出(MIMO)天线以及八木天线中。本研究课题主要创新工作有:1.提出了一种在宽频段内实现天线辐射方向图稳定的方法。通过合理的设计偶极子和反射板的位置,就可以使天线在宽频段内实现稳定的辐射方向图。我们设计、加工和测试了两个单极化的基站天线来验证我们所提出的方法。测试结果显示,我们设计的天线都在宽频段内实现了稳定的辐射方向图、良好的阻抗匹配以及低交叉极化。2.为了减小电磁波传播的多径衰落效应以及为了能够和射频封装器件相连接,我们提出了一款±45°双极化差分基站天线。这款天线水平面内半功率波瓣宽度稳定在65度左右,非常适合应用在三扇区的蜂窝基站天线中。3.提出了两种改善±45°双极化基站天线交叉极化比的方法。第一种方法是在一个基本的±45°双极化基站天线周围加载4个水平的寄生单元。第二种方法是在一个基本的±45°双极化基站天线和反射板之间加载四个垂直的寄生单元。我们设计、加工、测试了两款±45°双极化基站天线来验证我们所提出两种的方法。4.提出了两种实现圆极化天线在宽角度内低轴比的方法。第一种方法是将四个偶极子围成正方形。我们将两对相互垂直放置的偶极子幅度相等相位相差90度激励。只要合理的设计偶极子之间的距离,就可以使圆极化天线在宽角度内实现低轴比。为了减小圆极化天线的整体尺寸,我们用弯折偶极子代替了直线型偶极子。第二种实现圆极化天线宽角度内低轴比的方法是在一个交叉偶极子圆极化天线和反射板之间加载四个垂直的寄生单元。我们设计、加工、测试了三款圆极化天线来验证我们所提出的两种方法。5.提出了一种由H型定向天线组成的MIMO天线。我们提出的H型定向天线在没有引向器和反射器的情况下,在水平面内实现了很高的前后比。我们将四个这样的H型定向天线围成方环形组成一个紧凑的MIMO天线。这个MIMO天线单元之间的隔离度都很高。我们将这款MIMO天线加工测试并评估了它的MIMO特性。6.提出了带有阶梯型反射器的八木天线。由于反射器采用的阶梯型结构,因此反射器的长度可以比偶极子要短。我们通过分析一个偶极子和一个寄生单元的等效电路解释了阶梯型结构可以缩短反射器尺寸的原因。我们将这种阶梯型反射器应用在了一个同轴馈电的八木天线和一个差分馈电的八木天线当中,并将这两个八木天线加工测试。
[Abstract]:With the arrival of 4G era and the development of 5G era, the role of polydipole antenna in mobile communication system will become more and more important. Polydipole antennas can be widely used in base station antennas, circularly polarized antennas, In the multi-input multiple-output MIMO-antenna and the Yagi antenna, the main innovative work of this research is: 1.A method to stabilize the radiation pattern of the antenna in the broadband band is proposed. The position of the dipole and the reflector is reasonably designed. We design, process and test two single-polarization base station antennas to verify our proposed method. Our antennas are designed to achieve stable radiation patterns, good impedance matching and low cross-polarization. 2. In order to reduce the multipath fading effect of electromagnetic wave propagation and to be able to connect with RF packaging devices, We propose a 卤45 掳dual-polarization differential base station antenna. The width of the half-power lobe in the horizontal plane is stable at about 65 degrees. This paper presents two methods to improve the cross-polarization ratio of 卤45 掳dual polarization base station antenna. The first method is to load 4 water around a basic 卤45 掳dual polarized base station antenna. Flat parasitic elements. The second method is to load four vertical parasitic elements between a basic 卤45 掳dual-polarized base station antenna and a reflector. Processing, Two 卤45 掳dual-polarization base station antennas are tested to verify the two methods proposed. 4. Two methods are proposed to realize the low axis ratio of circular polarized antennas at wide angles. The first method is to encircle the four dipoles into squares. Two pairs of dipoles placed perpendicular to each other are excited by 90 degrees in equal phase. If the distance between dipoles is reasonably designed, In order to reduce the overall size of circularly polarized antenna, a low axis ratio can be realized at a wide angle. We replace the linear dipole with a curved dipole. The second method to realize the low axial ratio in the wide angle of a circular polarized antenna is to load four vertical parasitic elements between a cross dipole circular polarization antenna and a reflector. Three circularly polarized antennas are processed and tested to verify the two methods proposed. 5. A MIMO antenna consisting of H-type directional antennas is proposed. The H-type directional antenna is presented without a guide and reflector. We make four H-shaped directional antennas into a square ring to form a compact MIMO antenna. The isolation between the MIMO antenna elements is very high. We will take this MIMO antenna. Processing test and evaluation of its MIMO characteristics. 6. Proposed a step reflector with the Yagi antenna. So the length of the reflector can be shorter than that of the dipole. We explain the reason why the step structure can shorten the size of the reflector by analyzing the equivalent circuit of a dipole and a parasitic unit. The emitters are used in a coaxially fed Yagi antenna and a differential fed Yagi antenna. And the two Yagi antenna processing test.
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TN821.4

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