三频段MIMO天线的双中和线去耦合设计

Double neutralization lines decoupling design for tri-band MIMO antenna

设计了一款可以应用于LTE2300和WiMAX3.5/5.8 GHz频段的多输入多输出(MIMO)天线,其由2个相距4 mm的对称单元组成,且每个单元由“己”和“弓”形的弯折线构成。采用背对背布局形式的组阵方式来实现低频段的高隔离度。同时,为了提高中频段和高频段端口间的隔离,将双中和线去耦结构加载至天线单元两端,并对该去耦结构进行了理论分析和实验验证。利用HFSS仿真软件对MIMO天线的性能参数包括S参数、辐射模式、增益和包络相关系数(ECC)等进行研究。结果表明,在频点为3.5 GHz处隔离度提高25 dB,在频点为5.7 GHz处实现了30 dB的隔离度。此外,该天线具有全向辐射特性,在工作频段内具有较好的分集增益。

A tri-band multiple-input-multiple-output(MIMO)antenna is designed to cover the LTE2300 and WiMAX 3.5/5.8 GHz.It consists of two symmetrical elements separated by 4 mm,and each include"hex"and"bow"shaped bend lines.The antenna units adopt a matrix of back-to-back layout to achieve high isolation in the low frequency band.Mean⁃while,in order to improve the isolation between the mid-band and high-band,the dual neutralization lines decoupling structure is loaded to both ends of the antenna units.And the decoupling structure is theoretically analyzed and experi⁃mentally verified.The performance parameters of MIMO antenna including S parameters,radiation mode,efficiency and envelope correlation coefficient(ECC)are analyzed by HFSS simulation software.The results show that 25 dB is in⁃creased at 3.5 GHz and the isolation is 30 dB at 5.7 GHz.Besides,the antenna has an omnidirectional radiation charac⁃teristic and better diversity gain within the operating frequency band.