基于超宽带阵列截断效应抑制的新型高增益多馈超宽带天线研究

Ultra-wideband (UWB) antenna is a key part of impulse radio system, whose high-gain design is one of the important subjects in ultra-wideband radar field. UWB array is an excellent candidate for realizations of ultra-wideband and high-gain, and truncation effect suppression is a necessary step in UWB array design. Based on the UWB array with truncation effect suppressed, a new idea on high-gain design of UWB antennas is proposed in this project. Tapered slot antennas, dipole antennas and horn antennas, the three main kinds of UWB antennas with good characteristics in both time and frequency domains, are the experimental subjects in this project. Firstly, the mechanism and suppression methods of truncation effect are studied by analyzing the coupling among elements in UWB arrays. Secondly, multi-fed structures of the three kinds of UWB antennas are implemented by constructing a small broadside array with only several elements in the size of their conventional structures. And the methods for realizations of ‘coupling utilizing among feeding points’ and ‘uniform aperture field’ are explored, as a result of which the multi-fed structures of the UWB antennas can obtain similar operating band but higher gain by comparing with conventional structures in the same size. Finally, the designed antennas are fabricated and measured. New theories and methods about high-gain multi-fed UWB antenna design are concluded. The idea proposed is original and creative for designs of high-gain UWB antennas, which is significant for both the scientific research and UWB applications.

超宽带天线是脉冲无线电系统的关键组成部分，其高增益设计是超宽带雷达领域的重要研究课题。超宽带阵列是实现超宽带、高增益的优秀选项，截断效应抑制是其工程实现的必要环节，基于此，本项目提出了一种新的高增益超宽带天线设计思想。以渐变开槽天线、偶极天线、喇叭天线三类具有良好时域特性的超宽带天线为主要对象，首先，通过分析无限和有限阵列中单元间耦合特性，探索截断效应的产生机理和抑制技术；其次，在传统天线结构尺寸范围内构建多馈结构（含几个单元的小型边射阵列），基于截断效应抑制技术，探索多馈结构中“馈点间耦合利用”和“口径场均匀分布”的解决方法，实现不小于同尺寸传统结构工作频带内的高增益；最后，对设计的天线进行加工、测量，总结研究成果，形成高增益多馈超宽带天线的设计理论和方法。这一思想是对超宽带天线高增益设计的创新性补充，具有重要的科学意义和应用价值。

超宽带天线的高增益实现是天线工程中的重要研究方向，高增益超宽带天线在现代通信系统和雷达系统中的应用前景也较为广阔。本项目由阵列天线的均匀口径场分布及高增益特性出发，以传统天线在尺寸不变情况下阵列化获得多馈结构，通过馈点间耦合利用保持超宽带阻抗特性，通过利用超宽带天线有限阵列边缘截断效应抑制结构调整口径场均匀分布，最终实现超宽带高增益设计。设计了双馈线性渐变开槽天线、混合式渐变开槽天线、高隔离度双极化天线，通过结构设计完成了耦合利用和口径场均匀分布，实现了超宽带高增益辐射；设计了低交叉极化双馈对跖Vivaldi天线，为对趾Vivaldi天线提出了除传统结构和平衡对趾结构外第三种结构，能够以双层结构实现超宽带高增益低交叉极化辐射。分析了偶极子无限、有限阵列中单元间耦合特性及反射地面、介质匹配层产生的影响；研究了双馈偶极子天线的工作特性，探索了微带天线阵列中单元间耦合特性，微带天线阵列单元间耦合利用、耦合抑制的技术及八木天线阵列单元间解耦技术，设计了相应的天线阵列。研究了TEM喇叭天线有限、无限阵列的工作特性及单元间耦合特性；分析了双馈主模喇叭天线、TEM喇叭天线的辐射特性，改善了喇叭天线的口径分布均匀性，提高了增益；提出了基于渐变开槽天线结构和TEM喇叭天线结构的新型混合式结构天线，天线在性能上保持了TEM喇叭天线的优点，结构上利用印制电路板即可实现。本项目基于耦合利用和口径场调整研究了平衡馈电天线的超宽带高增益多馈结构设计，并拓展研究了天线阵列单元间的耦合抑制，提供了丰富的阵列单元间耦合调控手段。项目研究成果对超宽带天线的工程应用，对天线阵列的单元间耦合控制理论与方法发展，具有重要的推动作用。