一种面向5G通信的宽带8单元MIMO天线设计

提出了一种面向5G的宽带8端口多输入多输出（multiple-input multiple-output，MIMO）天线.天线单元采用多枝节单极子结构，能够激发多模态，且能覆盖多频段.同时，采用弯折结构来实现小型化，且在相邻单元之间设计T形突出地结构来提高隔离度.仿真和实测结果显示，该天线在3~7.1 GHz内回波损耗大于10 dB，在3.3~7.1 GHz内隔离度高于15 dB.因为进行了有效的去耦，天线体现出明显的辐射分集特性，天线在目标sub-6 GHz频段内的包络相关系数（envelope correlation coefficient，ECC）接近0.在一8×8 MIMO系统中，计算得到的峰值遍历信道容量为43 bps/Hz，达到传统2×2 MIMO上限值的3.74倍.该8单元MIMO天线具有良好的分集和复用能力，能满足5G通信在sub-6 GHz的高速数据传输需要.

Design of a wideband 8-element MIMO antenna for 5G communication

A wideband 8-port multiple-input multiple-output (MIMO) antenna for 5G is proposed. The antenna element is a multi-branch monopole. Its structure can yield multiple modes to cover multiple bands. A folded structure is also employed to achieve antenna miniaturization. To enhance isolation, T-shaped protruded ground structures are designed and embedded between the adjacent antenna elements. The simulated and measured results indicate that the return loss of the proposed antenna is larger than 10 dB in the 3-7.1 GHz band, and the isolation is higher than 15 dB in the 3.3-7.1 GHz band. Benefitting from effective decoupling, the proposed antenna shows distinct radiation diversity characteristic. The envelope correlation coefficient (ECC) of the proposed antenna is close to zero in the targeted sub-6 GHz bands. The calculated peak ergodic channel capacity in an 8×8 MIMO system is 43 bps/Hz, reaching up to 3.74 times of the upper limit for conventional 2×2 MIMO. The proposed 8-port MIMO antenna has good diversity and multiplexing capabilities, and it is competent for high-speed data transmission for the 5G communication in the sub-6 GHz bands.