多输入多输出通信基站扇区天线的研究.pdf

南京邮电大学硕士研究生学位论文 摘要 I 摘 要 基于多输入多输出（MIMO）技术的IMT-Advanced系统由于其更快速率、更高频谱利用率等特点备受关注而作为通信系统的重要组成部分，适用IMT-Advanced移动通信系统工作频带的基站天线，具有重要的研究意义 本文以微带贴片型天线模型设计出一套双极化扇区天线同时选择微带型威尔金森功率分配器作为天线馈电系统，软件仿真以及实物测试表明所设计天线的各项参数能够满足性能指标 通过分析对称振子天线宽频带技术，选择蝶形振子天线作为扇区天线另一种模型，软件设计以及仿真结果对比证实蝶形天线具有更宽的阻抗带宽基于多谐振实现扩展阻抗带宽的电路原理，通过进一步改变蝶形天线结构设计出三叶草型天线，对比仿真结果验证能够进一步扩展天线阻抗带宽，并且能够在半功率波束宽度内有效的抑制交叉极化电平 在振子上电流分布比较集中的位置开槽可以改善天线的低频特性根据该原理，提出了一种新的天线单元模型，相比蝶形天线实现了阻抗带宽的更进一步展宽。

它能够同时工作于三个所设计的工作频带，从而减少了所需天线的数量；而且也有较低的交叉极化电平同时针对振子天线设计出两种威尔金森功率分配器，通过对比性能和加工复杂度，选择其中一种作为振子天线馈电系统的单元所选择单元在同等输出端口隔离度以及阻抗带宽条件下比较容易加工实现 本文所提出的三叶草开槽型基站扇区天线模型，能够覆盖多频带以及具有较低的交叉极化电平，而且结构相对简单，适合工程应用 南京邮电大学硕士研究生学位论文 Abstract II Abstract IMT-Advanced communication system which is based on MIMO communication technology is attracted much attention because of its features including faster rate and higher spectrum efficiency. Therefore, as a key component of the communication system, base station antennas for IMT-Advanced frequency band, which is much important for the system implementation should be researched. A dual polarization sector antenna using microstrip patch as its element is adopted in this thesis. Microstrip Wilkinson power divider is chosen as the feed system and the desired requirements of characteristic parameters can be achieved through simulation results comparing with testing results. By means of broadband technology of symmetric dipole, bow-tie antenna has been selected as model of another base station sector antenna. The simulation results verify that the bow-tie antenna possessed a wider bandwidth than the microstrip patch antenna. Based on the principle that multiple resonances may achieve a wider impedance bandwidth, a new antenna structure named clover is proposed to broad the bandwidth furthermore. The cross polarization level is suppressed at the half-power beam width, which is superior to that of the bow-tie antenna. The low frequency characteristic can be improved if the antenna is slotted where the current magnitude is large. A new antenna model is proposed based on the principle and the wider frequency band than that of the clove antenna is achieved. It may work in three operation bands simultaneously. Therefore, fewer antennas are required and low cross polarization level is obtained. For the antenna feeding, two kinds of Wilkinson power divider are designed. By comparing the performances and fabrication complexities, one of the power divider is selected as the element of the antenna feed system. The selected power divider is relatively fabrication at the same performances of output port isolation and impedance bandwidth. The slotted clover base station sector antenna possesses the performances of multiband coverage, low cross polarization level and relatively simple structure. It is suitable for engineering applications. 南京邮电大学硕士研究生学位论文 目录 III 目 录 摘 要...............................................................................................................................................I Abstract ......................................................................................................................................... II 目 录............................................................................................................................................III 第一章 绪论................................................................................................................................1 1.1 课题研究背景及意义............................................................................................................................. 1 1.2 国内外研究现状...................................................................................................................................... 2 1.3 主要贡献和论文组织............................................................................................................................. 4 1.3.1 主要贡献......................................................................................................................4 1.3.2 论文组织......................................................................................................................5 第二章 基站扇区天线的特点.....................................................................................................6 2.1 天线的基本特性参量............................................................................................................................. 6 2.2 基站扇区天线的主要指标要求........................................................................................................... 7 2.3 本。