空间受限的多频段终端MIMO天线研究

The investigation into multiband/wideband LTE (Long Term Evolution)/GSM (Global System for Mobile communication )/UMTS (Universal Mobile Telephone Service) decoupled MIMO (Multiple-Input Multiple-Output) antennas for wireless terminal applications has been a hotspot in recent years. The fact is that the performances of terminal antennas are limited to the small-size spaces occupied by the antennas and the effects of the head-hand model. The main hallenge in this subject is how to alleviate the effects of the head-hand model, widen the operating bandwidth of the antenna in the small-size space, and decoupling the strong coupling between two MIMO antenna elements in a closely-space arrangment. In the area of the terminal MIMO antenna, there are many methods for decoupling the strong coupling between two MIMO antenna elements which are reported in the open literatures,including decoupling network, parasitic element, defected ground structure, and neutralization line (NL) technique, etc. It is noteworthy that the previous studies on decoupling methods for terminal MIMO antennas are mainly focused on either the too large space of the antenna or the upper-band operations. However, the decoupled MIMO antennas being capable of covering the lower-bands of LTE700/GSM850/900 are more challenging and desired in practical applications. So, in this proposal, a novel multiband decoupled MIMO antenna for LTE/GSM/UMTS terminal applications is proposed. The proposed decoupled MIMO antenna adopts the coupled-fed antenna technique to alleviate the effects of the head-hand model, employs the frequency reconfigurable antenna technique to realize the multiband operation of the antenna, and uses the neutralization line technique to decouple the strong coupling between two MIMO antenna elements, which is promising for the industry applications.

尽管终端MIMO天线已经得到了较广泛的研究，但仍存在以下科学难题：头手模的影响、空间受限与多频段/宽带化的矛盾、以及MIMO天线单元间的近距强互耦。这些难题使得MIMO天线在新一代移动通信终端的应用一直进展缓慢。为此本项目开展如下工作：探索头手模影响终端天线性能的机理，提出在低频段具有类似Loop天线原理的耦合馈电式天线方案，使得天线的效率比传统方案在低频段至少提升50%、在高频段至少提升20%；提出终端MIMO天线框架下的频率可重构天线，在典型的终端天线的空间尺寸下支持对LTE/GSM/UMTS全频段的覆盖，真正解决终端MIMO天线的空间受限与多频段覆盖的难题；研究空间受限条件下的终端MIMO天线的近距强互耦机理，结合频率可重构天线，提出基于中和线的终端MIMO天线宽带化去耦方法；最后应用上述理论及方法，提出真正切合工业界工程需要的多频段终端MIMO天线解决方案及工程样品.

MIMO天线作为新一代移动通信最核心的关键技术之一大大提升了网络的系统性能。虽然MIMO天线已经过学术界的大量研究并已获得广泛应用，但在终端方面的应用却由于诸多理论及技术难题尚存在不少挑战。本课题就是在此背景下针对终端MIMO天线在空间受限条件这一重要的理论与应用的关键问题，主要围绕头手摸对天线性能的影响、终端天线的多频段/宽带化、可重构技术、MIMO单元天线之间的电磁去耦等方面展开。经过四年的持续研究，系统研究了头手模影响终端天线的物理机理，提出了一种结构简单紧凑的双环天线及MIMO天线。基于互补的振子天线和缝隙天线极化正交的特点，设计了一款基于混合天线的8单元正交双极化MIMO天线。这些理论研究成果分别改善了头手模对天线性能的影响、克服了终端天线小型化与宽带化的矛盾、解决了空间受限的终端MIMO天线单元间的近距强互耦难题。. . 发表项目负责人为第一/通讯作者的本领域主流SCI学术期刊论文24篇，其中IEEE/IET期刊论文22篇，获授权发明专利6项。部分项目成果在产业界获得应用推广。并且依托该项目的部分成果获得两项省部级科技奖项（2017年山东省科技进步奖二等奖、2017年教育部自然科学奖二等奖） .