一种基于缺陷地结构的双单元MIMO天线阵宽带解耦方法

基于缺陷地结构互耦抑制机理,研究了手机移动终端双单元多输入多输出(multiple input multiple output,MIMO)天线阵实现宽带解耦方法.该方法是在T型分支上加载3对不同长度的开口槽线,形成1对L型单极分支和2对I型单极分支,分别在不同频段内实现解耦,再联合实现宽带解耦的方式.测试结果表明,以-6 dB的反射系数值为标准,带宽能覆盖低频段75 MHz(685 MHz~760 MHz)和50 MHz(910 MHz~960 MHz),高频段880 MHz(1.65 GHz~2.53 GHz),天线单元间的耦合程度小于-15 dB,满足GSM900,LTE700,GSM1800,GSM1900,UMTS,LTE2300,LTE2500和2.4 GHz WLAN等常用通信频段的带宽需求,对于目前2G,3G,4G通信系统共存的市场局面也拥有良好的实际运用价值.该天线的增益在工作频段0.51~2.45 dBi变化,效率在60%以上,显示出了良好的辐射性能.

A dual-antenna MIMO array wideband decoupling method using defected ground structure

In this paper, a wideband decoupling method of the dual-antenna MIMO array is studied for mobile terminals based on decoupling mechanism of defected ground structure. The method is to etch three pairs open ended slots of various lengths on a T-shaped metal ground to form a pair of L-shaped monopole branches and two pairs of I-shaped monopole branches. These branches are designed to suppress the mutual coupling between antenna elements at different bands, which forms a wideband decoupling. Measured results show that, with 6 dB reflection coefficient as a standard, the operating bandwidths are 75 MHz(685 MHz~760 MHz), 50 MHz(910 MHz~960 MHz), 880 MHz(1.65 GHz~2.53 GHz), respectively. The measured mutual coupling between antenna elements is less than -15 dB at all frequency ranges, which meets the requirements of the GSM900, LTE700, GSM1800, GSM1900, UMTS, LTE2300, LTE2500, 2.4 GHz WLAN bands. Furthermore, it is also a good practical application in the market where 2G, 3G and 4G mobile communication system coexisted. Finally, the antenna gain is varied from 0.51 dBi to 2.45 dBi, and the efficiency is above 60% at working bands, which shows that MIMO array has a well radiation performance.