【作者】 薛飞；

【导师】 程钰间；

【作者基本信息】 电子科技大学 ， 电磁场与微波技术， 2017， 硕士

【摘要】 天线一般工作在其辐射远场区域。对于某些特定场合,要求天线辐射的能量聚集在其近场区域的某一特定点上,这就需要近场聚焦天线。针对近场聚焦天线的研究已经持续了很长时间。在特定区域具有高能量密度的近场聚焦天线不仅可以用于提高医学与工业检测系统的探测和成像能力,还能用于门禁系统、微波无线输能系统、射频识别系统以及微波无线电系统等方面,具有广泛的应用前景和研究价值。不同应用场合对近场聚焦天线的需求也不相同。在微波热疗应用中希望利用最大功率加热癌组织,而不希望其对邻近健康组织产生危害;在非接触式微波感应中并不希望在焦点旁边有较高副瓣影响其准确性。因此,对近场聚焦天线实现低副瓣设计是降低副焦瓣影响的有效方法。当近场聚焦天线用于大面积检测时,可以通过需要焦斑扫描来扩大覆盖或提高位置定位精度。本文针对近场聚焦阵列天线相关问题展开研究,具体体现在:首先,在分析平面天线近场聚焦原理基础上,结合基片集成波导与金属圆波导实现了电磁波的近场聚焦。通过对基片集成波导近场聚焦天线的子部件进行分析,并对天线焦距与焦斑特性进行了讨论,最终对Ka频段基片集成波导近场聚焦天线进行设计、加工与实测。在此基础上,进一步研究近场聚焦天线的副瓣抑制问题。通过阐述近场区域低副焦瓣与圆极化的生成原理,即利用基片集成缝隙天线通过多元法实现圆极化,基于基片集成波导功分网络通过泰勒分布赋形实现所需近场副瓣电平,最终对K波段低副焦瓣双圆极化近场聚焦天线进行设计、加工与测试。最后,结合改进的基片集成波导罗特曼透镜与基片集成缝隙天线缝隙阵列天线,实现了Ka波段多焦斑天线。为了将基片集成罗特曼透镜作为聚焦波束形成网络,对传统罗特曼透镜的相移网络进行修改以满足波束聚焦和扫描的要求。当从不同的输入端口激发时,焦点可实现横向扫描。最终对Ka波段基片集成改进罗特曼透镜多焦斑近场聚焦天线进行设计、加工与测试。更多还原

【Abstract】 The antenna generally operates in the far field of the radiation.For some special occasions,it is necessary to gather the energy of the antenna radiation on a particular point in the near field.Near-field-focused antenna research have been studied over a long time.Near-field-focused antenna with high energy density in a specific area can not only be used to improve the detection of medical and industrial detection system and imaging ability,can also be used for access control systems,microwave wireless power transmission system,radio frequency identification system and microwave radio systems.It has the widespread application prospect and the scientific research value.Due to different applications of near-field-focused antenna,the demands for the focal point’s characteristics are also different.For example,in the case of microwave hyperthermia applications,it is desired to use the maximum power to heat the cancer tissue without doing harm to healthy tissue.The reason why reducing the side-lobe of focal point in the non-contact microwave induction is that higher side-lobe will have bad influence on its accuracy.The realization of low side-lobe design for near field focusing antenna is an effective way to reduce the influence of side lobes.When the near field focused antenna is used for large area detection,multiple focus points are required to expand coverage or improve position accuracy.In this paper,the near-field-focused array antenna have been studied,embodied in:Firstly,the near-field-focused principles of the planar antenna are analyzed,and the near-field-focused is realized based on the integrated waveguide and the metal circular waveguide.The sub-components of the near-field-focused antenna of the substrate integrated waveguide are analyzed,and the relationship between antenna focal length and focal spot characteristics has been discussed.Finally,the processing and measurement of Ka band substrate integrated waveguide near-field-focused antenna are presented.Based on the previous near-field-focused antenna,the side lobe suppression of the near field focused antenna is further studied.By analyzing the generation principle of the low side lobe and circular polarization in the near field region,the realization method is analyzed.That is,the circular polarization is realized by the multivariate method using the substrate integrated slot antenna,and the required near field side lobe level is achieved by integrated waveguide network with Taylor distribution.The design,fabrication and test results of the Ka band dual circular polarization near-field-focused antenna with low side lobe are presented in the end.Finally,Ka band near-field-focused antenna with multi spot is realized by combining the substrate integrated waveguide modified Rotman lens and the substrate slot antenna array.In order to integrate the Rotman lens as a focused beam forming network,the conventional lens phase shift network is modified to meet the requirements of beam focusing and scanning.When different input ports are excited,the focus can be scanned horizontally.In the end,the design,fabrication and testing results of Ka band substrate integrated focused multi beam antenna based on the modified Rotman lens are presented.更多还原