4G移动通信中的MIMO天线设计与性能研究

发布时间：2018-09-09 18:45

【摘要】：随着传输速率和通信质量的提高,频谱资源稀缺和多径衰落等问题日益突出,MIMO系统可充分利用空间资源,有效地提高传输速率和频谱利用率。随着手机超薄化、智能化的发展趋势,手机等移动终端中留给天线的空间越来越小,且4G网络需同时兼容2G、3G网络,这就需要MIMO天线不仅要尺寸小还需具备较宽的频带。同时,金属边框的引入严重影响了智能机内置天线的阻抗匹配和辐射性能,这大大增加了MIMO终端天线的设计难度。本文结合已有文献详细分析了几款小型化宽频化天线设计方案,并在此基础上提出了三款智能机MIMO天线的设计方案。首先,本文提出了一款基于混合去耦结构的多频段智能机MIMO天线的设计方案,天线单元由耦合馈电的环形天线和单极子天线组成,由中和线和突出地组成的混合去耦网络大大提高了MIMO系统的隔离度,且天线结构简单、紧凑,易于加工。然后,本文提出了一款基于环天线的金属边框智能机MIMO天线设计方案,金属边框被分为四部分,通过倒L型馈电枝节耦合馈电分别在天线的低频段和高频段产生谐振,与内置耦合环天线共同实现了对WWAN/LTE频段的覆盖,且两个天线单元分别在系统基板的两个角落,实现了良好的隔离效果。最后,本文提出了一款基于Monopole天线的金属边框智能机MIMO天线的设计方案,天线单元由金属边框与弯折型Monopole天线组成,金属边框通过Monopole耦合馈电谐振在低频段,Monopole天线与金属边框的高阶谐振点共同覆盖天线的高频段,通过在地板上加载弯折开槽线,MIMO系统的隔离度得到明显提高。本文对所提出的三种设计方案的可行性均进行了实验验证,测试结果表明三款天线均能满足带宽、隔离度及辐射性能的要求;为分析天线与人体之间的相互作用,对其中两款天线进行了手头模型的仿真,结果表明天线性能稳定,SAR值低,满足实际工程需求。
[Abstract]:With the improvement of transmission rate and communication quality, the problems of spectrum scarcity and multipath fading are becoming more and more important. MIMO systems can make full use of space resources and effectively improve the transmission rate and spectrum efficiency. With the thinning of mobile phones and the trend of intelligent development, the space left to antennas in mobile terminals such as mobile phones is becoming smaller and smaller, and 4G networks must be compatible with 2GN 3G networks at the same time, which requires MIMO antennas not only to be small in size but also to have a wide frequency band. At the same time, the introduction of metal border seriously affects the impedance matching and radiation performance of the built-in antenna of the smart machine, which greatly increases the design difficulty of the MIMO terminal antenna. In this paper, several design schemes of miniaturized broadband antennas are analyzed in detail, and three MIMO antennas for smart machines are proposed. First of all, this paper presents a design scheme of multi-band smart machine MIMO antenna based on hybrid decoupling structure. The antenna unit is composed of a coupling fed ring antenna and a monopole antenna. The hybrid decoupling network, which consists of neutralization line and outburst, greatly improves the isolation of MIMO system, and the antenna structure is simple, compact and easy to process. Then, a design scheme of metal frame smart machine MIMO antenna based on ring antenna is proposed. The metal border is divided into four parts, which generate resonance in the low frequency band and high frequency band of the antenna by coupling the feed segments of the inverted L type. The WWAN/LTE band coverage is realized together with the built-in coupling loop antenna, and the two antenna elements are in two corners of the system substrate respectively, and the good isolation effect is achieved. Finally, a design scheme of metal frame smart machine MIMO antenna based on Monopole antenna is proposed. The antenna unit is composed of metal frame and bending Monopole antenna. The metal border is fed by Monopole coupling resonance in the high frequency band of the antenna and the high order resonance point of the metal frame. The isolation degree of the Monopole system is obviously improved by loading the curved slotted line on the floor. Experimental results show that the three antennas can meet the requirements of bandwidth, isolation and radiation performance. The simulation results of two antennas on hand show that the antenna performance is stable and the SAR value is low, which meets the practical engineering requirements.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN828.6

【参考文献】