设计了一种适用于LTE基站天线系统的宽频带±45°双极化辐射单元.该辐射单元采用微带巴伦结构,用双倒L形微带馈线进行耦合馈电,并对该微带馈线进行切角、增加横向枝节、改变开路枝节宽度有效地扩展了天线的带宽.仿真及实测结果表明,在1.7~2.7 GHz频带内,该辐射单元的电压驻波比(voltage standing wave ratio,VSWR)小于1.4,隔离度大于25 dB,相对带宽超过45.4%.利用该辐射单元组成八单元阵列天线后辐射参数良好,水平面半功率波束宽度稳定在65°±5°,主极化前后比大于25 dB,轴向交叉极化比大于18 dB,基本能满足移动通信基站天线的指标要求.%A broadband ±45° dual-polarized radiation element is designed for LTE base station antenna systems.The proposed radiation element has microstrip Balun structure,it is fed by double inverted-L probes,and the bandwidth can expanded efficiently by cutting the angle of microstrip line,adding the branch and changing the width of the open branch.The simulation and measured results show that the proposed radiation element achieves a common impedance bandwidth of 1.7~2.7 GHz(VSWR < 1.4)at both input ports,the bandwidth overs 45.4%,it also has good performance in isolation,which is more than 25 dB between the two input ports.The eight-element antenna show it has excellent performance in radiation pattern,the half-power beamwidth at H-plane is stabled in 65°±5°,the front-to-back ratio is more than 25 dB and the axial cross-polarization ratio is more than 18 dB,so the antenna can satisfies the demand of the mobile communication base-station antenna.
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