一种新型的宽带双极化基站天线

A novel wideband dual-polarized base-station antenna

提出一种新型的宽带双极化辐射单元，该辐射单元的辐射臂由普通方形对称振子的辐射臂向内折弯构成，形成一个附加小U型，它可以展宽带宽，且缩小辐射单元的口径面积；采用内部相向开口的半开放式巴伦结构，并用双倒L型耦合馈电，改善了隔离特性和波束收敛性。利用这种辐射单元组阵，形成四单元的基站天线，仿真结果表明，1．7～2．7GHz频段内，该辐射单元的电压驻波比（voltagestandingwaveratio，VSWR）小于1．4，隔离度小于-30dB；同时，利用该辐射单元组成的四单元基站天线辐射参数优良，水平面半功率波束宽度达到65°±5°，±60°交叉极化鉴别率小于-12dB，前后比小于-25dB。

A novel wideband dual-polarized radiation element is presented, and the radiation arm of this element uses the ordinary square arm of dipole to form an additional U-shaped structure bending inward. It has a wider bandwidth and narrow size. Meanwhile, the balun has an internal semi-opening structure. This element is fed by double inverted-L probes. The i- solation and beam convergence are improved. Then, an antenna with four of this element is simulated. The radiation ele- ment achieved a common impedance bandwidth of 1.7 - 2.7 GHz （ VSWR 〈 i. 4） at both input ports, it also has good per- formanee in isolation, which is more than -30 dB between the two input ports. Also, the antenna has an exeellent per- fornlanee in radiation pattern. Across the entire operating frequency, the measured half-power beamwidth in the H-planes is within 65 °± 5°,the cross-polarization levels is less than - 12 dB and the front-to-back ratio is less than -25 dB.