【作者】 张建；

【导师】 翟会清；

【作者基本信息】 西安电子科技大学 ， 电磁场与微波技术， 2015， 硕士

【摘要】 近年来,随着现代科学技术的快速发展,人们对通信设备的要求越来越高,这为无线通信的质量和传输速率提出了巨大的挑战。天线作为无线通信的终端,扮演着十分重要的作用,性能优良的天线可以为人们提供更优越的通信质量和通信速率。多输入多输出(Multi-input and Multi-output,MIMO)技术在提高传输速率和信道容量方面具有独特的优势,其与天线的结合将为当前的无线系统提供质的飞跃。此外,当前无线系统多个模式共存的特点,多个天线工作在多个频点,它们之间将会产生强烈的耦合,影响天线系统的性能。因此设计应用于MMO系统的多频单元和阵列就变得非常有必要。论文主要内容为;本文通过引入课题背景以及意义,阐述了MIMO通信技术中提高隔离度的必要性,介绍MIMO系统基本理论,并针对MIMO技术中常用的去耦手段做了详细的介绍。本文主要研究适用于无线系统中双频模式MIMO阵列。通过对天线工作特性和去耦机理的分析和研究,提出三款具有良好工作特性的双频MIMO阵列。1.双频PIFA天线MIMO阵列设计。本文基于PIFA天线的结构和工作原理,结合天线开槽技术,设计了两款双频PIFA天线,天线单元均可覆盖WLAN和WiMAX频段,以此组成六元MIMO阵列,采用倒π型枝节和T型枝节加载在天线单元之间,实现了MIMO天线隔离度的提高。2.双频磁电偶极子天线MIMO阵列设计。本文基于磁电偶极子的结构和工作原理,设计了一款双频磁电偶极子天线,天线单元可覆盖WLAN和WiMAX频段,采用极化分集技术将天线两两垂直放置组成六元MIMO阵列,实现单元之间隔离度的有效提高。3.高增益双频偶极子天线MIMO阵列设计。该天线阵列由六个双频偶极子天线单元构成。运用天线的极化分集原理,实现MIMO天线阵列在有效空间内多个天线的高隔离特性。同时,设计一款双频人工磁导体材料,将周期性人工磁导体背向放置与偶极子阵列下侧,实现天线的高增益、单向辐射特性,并在一定程度上降低了天线阵列剖物面。更多还原

【Abstract】 With the enormous development of wireless communications, lots of dependent is coming up to make wireless devices with better performance, bringing in great challenge for quality and speed of wireless communications. As an important part of wireless communication systems, antenna of great performance could provide better quality and higher speed of wireless communications. The adoption of MIMO(multiple input multiple output) scheme can raise communication speed and add to signal capacity with the usage of same frequency sources. The combination of MIMO technology and antenna provides a qualitative leap for current wireless communication. Besides, with the feature of multi-mode of antennas in the present system, the mutual coupling between antennas will make the properties of the antenna system poorer. Thus, it is in great need to design multi-band antenna elements and arrays for MIMO systems. The main study content of the thesis is showing below:The thesis describes the background and the significance about our research, and this thesis expounds the necessity of improving isolation in MIMO communications. Moreover, it introduces the fundamental theory of MIMO system, and the decoupling methods widely used in MIMO technology are also given in detail in this thesis.In this thesis, the design of a dual-band MIMO antenna for mobile communication has been studied. Three MIMO antenna arrays with good performance are proposed, based on the research and analysis of MIMO fundamental mechanism of antenna and decoupling.1、A dual-band PIFA antenna MIMO array. It combines the structure of PIFA antenna and the slotting technology, designing two kinds of dual-band antenna, which could cover WLAN and Wi MAX band respectively. The MIMO array is composed of six PIFA elements, with the inverse p-stub and T-stub placing between antennas, achieving the isolation enhanced in the MIMO system.2、A dual-band magneto-electric dipole antenna MIMO array. It designs a dual-band magneto-electric dipole antenna, covering WLAN and Wi MAX band respectively, based on the structure and working principle of magneto-electric antenna. The MIMO array is composed of six dual-band magneto-electric dipole antennas with polarization diversity technology and placed perpendicular every adjacent two, which enhances the isolation between antennas in the MIMO system.3、A dual-band dipole antenna MIMO array with high gain. It consists of six dual-band dipole antennas, applying polarization diversity between every two adjacent elements, demonstrating good isolation performance. It also provides a dual-band artificial magnetic conductor(AMC), and the periodical AMC surfaces are introduced underneath the dipole elements to achieve a unidirectional radiation, high gain and low profile.更多还原