宽带偶极子天线稳定展宽波束的方法研究

发布时间：2018-03-09 05:17

本文选题：基站天线　切入点：宽带天线　出处：《中国科学技术大学》2017年硕士论文　论文类型：学位论文

【摘要】：在现代移动通信基站系统中,为兼顾宽工作带宽和广覆盖范围的需求,宽带宽波束天线被广泛使用。由于基站中常用定向偶极子天线作为辐射单元,所以本论文改进了三种偶极子天线,在宽带内稳定提升了它们的波束宽度。在30%以上的相对带宽下,维持其波束宽度的变化范围不超过10°。对于电磁偶极子天线,利用下倾天线两臂与反射板内倾侧壁相结合来提升E面波束宽度。为改善波束宽度的带内稳定性,将辐射结构拆分为对称的多个分支。测试结果表明,在1.9～2.7GHz频段内,天线E面波束宽度被稳定展宽到95°～102°,H面波束宽度被稳定展宽到98°～104°。在阵列天线设计中,通过适当调整两臂下倾角度和侧壁内倾角度,继续保持了稳定的宽波束辐射特性。对于平面偶极子天线,设计了顶部加载平面结构的金属柱,作为寄生单元加载于天线反射板上,展宽了 E面和H面波束宽度。为分析其谐振特性,对加载寄生单元的天线提出了等效电路模型,并对模型进行了参数提取,对比仿真结果验证了正确性。然后采用多金属柱组合提升了天线的方向图带宽,测试结果表明,在2～2.7GHz频段内,天线E面波束宽度被稳定展宽到95°～103°,H面波束宽度被稳定展宽到96°～103°。在阵列天线设计中,由于阵元互耦导致了宽波束辐射性能退化。通过重新设计寄生单元的结构,将阵列天线的水平面波束宽度再次稳定展宽到98°左右。对于双极化偶极子天线,沿用上述提出的寄生单元并采用对角加载方式,展宽了水平面波束宽度。在1.8～2.6GHz频段内,其波束宽度被稳定展宽到85°～94°。在阵列天线设计中,通过引入金属隔离墙体,将异极化端口隔离度提高到了 26dB。
[Abstract]:In modern mobile communication base station system, wideband wide-beam antenna is widely used in order to meet the requirement of wide bandwidth and wide coverage. In this paper, three kinds of dipole antennas are improved, and their beamwidths are improved stably in broadband. At relative bandwidth above 30%, the variation range of beamwidth is not more than 10 掳. For electromagnetic dipole antennas, In order to improve the in-band stability of the beam width, the radiation structure is divided into symmetrical branches by combining the two arms of the downdip antenna with the inner tilting wall of the reflector. The experimental results show that the radiation structure is in the frequency range of 1.9 ~ 2.7GHz. The E plane beam width of the antenna has been steadily widened to 95 掳/ 102 掳/ H plane beam width to 98 掳/ 104 掳. In the design of the antenna array, the downward tilt angle of both arms and the inward angle of the sidewall are adjusted appropriately. For a planar dipole antenna, a metal column with a top loading plane structure is designed to be loaded on the reflector as a parasitic element. The beam width of E plane and H plane is broadened. In order to analyze its resonance characteristics, an equivalent circuit model is proposed for the antenna loaded with parasitic elements, and the parameters of the model are extracted. The correctness of the antenna is verified by comparing the simulation results. Then, the pattern bandwidth of the antenna is enhanced by the combination of polymetallic columns. The test results show that, in the frequency band of 2 ~ 2.7GHz, The E plane beam width of the antenna has been steadily broadened to 95 掳/ 103 掳/ H plane beam width to 96 掳/ 103 掳. In the design of antenna array, the radiation performance of the wide beam beam is degraded due to the mutual coupling of array elements. By redesigning the structure of parasitic elements, The horizontal plane beam width of the array antenna is extended steadily to about 98 掳again. For the dual-polarization dipole antenna, the parasitic element proposed above and diagonal loading method are used to widen the horizontal plane beam width. In the frequency band of 1.8m 2.6GHz, The beam width has been steadily widened to 85 掳~ 94 掳. In the design of array antenna, the isolation degree of different polarization ports is increased to 26 dB by introducing metal isolation wall.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN821.4

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