基于缝隙的超宽带端射天线及其共形阵列设计

发布时间：2018-07-03 15:58

本文选题：超宽带 + 端射　；参考：《电子科技大学》2016年硕士论文

【摘要】：天线作为无线通信系统的最前端,对整个无线通信系统的性能起着至关重要的作用。如今随着无线通信技术的高速发展,对天线性能的要求也越来越高。包括更宽的工作频带,比如符合FCC标准的UWB通信技术,其工作频段要求覆盖3.1~10.6GHz;更高的增益,比如用于目标追踪的高分辨率雷达天线,其增益要求常常达到30dBi甚至更高;更小的尺寸,比如无线终端天线,往往需要在极其有限的空间内排布6副及其以上的天线,此时需采用各种天线小型化技术缩减天线尺寸。在实际应用过程中,某些安装平台对天线系统的气动性有一定的要求,所设计的天线必须有利于共形安装以减少风阻等。端射天线作为一种有别于传统侧射天线的特殊天线结构,能够以较低的剖面在端向产生辐射,有利于共形安装。另一方面,对于需要共形设计的端射天线,其特殊安装环境使得天线的设计还需要考虑到金属表面、介质天线罩等的影响,所有这些都给天线的设计带来了极大的挑战。同时,传统的共形阵列主要是通过运用各种圆形阵列综合方法以达到波束全向覆盖或者全空域覆盖的目的。目前,国内外针对共形端射阵列设计的相关研究较少,但共形端射阵列在超宽带无源测向、相控阵雷达、反辐射导弹等领域发挥着越来越重要的作用。因此对有利用于共形安装的端射天线及其共形端射阵列的设计方法及相关理论进行深入的探究具备重要的意义。针对以上问题,本文研究设计了一种基于缝隙的超宽带端射天线,具备馈电结构简单、剖面较低、有利于共形安装等特点。同时对大金属柱体作为共形安装载体平台时对天线辐射特性的影响进行了探究,分析了平面波入射分层介质时电磁波的传输特性,为分析介质天线罩对天线性能的影响提供了基础理论依据。本文主要的研究工作及创新点如下:一、以折合缝隙作为基本辐射单元,并根据对数周期律准非频变原理,设计了宽带端射天线。针对这种端射缝隙天线设计过程中出现的波束上翘的现象进行了必要的理论分析,同时提出了通过延长端射缝隙前端地面的尺寸来改善波束上翘的现象。二、针对折合缝隙天线双向辐射问题,以及实际应用过程中需要共形安装在金属载体平台上的苛刻环境特点,对比研究了在缝隙天线一面添加金属反射板和金属背腔时,对缝隙天线性能影响的异同,得出缝隙天线加载背腔比加载反射板具有更好的辐射性能。同时深入研究了金属背腔关键参数对折合缝隙天线的影响机理,为下一章对数周期背腔折合缝隙天线的设计提供了初步的理论依据。三、提出利用倒置结构和在辐射口径上方添加介质覆层的方法来优化天线性能,使其在宽频带(6~18GHz)内实现了良好的匹配和稳定的端向辐射。仿真和实测结果显示这种天线在整个6~18GHz频带内实现了稳定的端向辐射,正端射方向的增益达到4dBi以上。四、提出了一种基于耦合原理的共面波导——微带线转换结构,有效地实现了本论文设计天线的宽带馈电需求。所提出的转换结构在6~18GHz内具有阻抗匹配良好,插损小的特点。五、对比分析了天线在单独使用和共形安装于金属柱体时辐射性能的差异,得出了金属载体对天线性能影响的规律。对平面波入射分层介质时的传输特性进行了理论分析,为分析天线前方介质天线罩对天线性能的影响提供了理论基础。对端射共形阵列的设计提供了指导。通过以上研究,本论文提出并设计的基于缝隙的超宽带端射天线有利于共形安装于金属载体平台,在6~18GHz内实现稳定的端向辐射,正端射方向的增益达到4dBi以上,同时具备较低的剖面,天线整体剖面尺寸仅为11.1mm。而对金属柱体和介质天线罩对天线性能的影响分析则有效地指导了共形端射阵列的设计。上述研究成果为宽带端射天线设计提供了新的思路,能很好地应用于超宽带无源共形测向阵、超宽带共形相控阵、弹载端射天线等。
[Abstract]:As the front end of the wireless communication system, the antenna plays an important role in the performance of the whole wireless communication system. With the rapid development of the wireless communication technology, the requirements for the performance of the antenna are becoming more and more high, including the wider frequency band, such as the UWB communication technology that meets the FCC standard, and the frequency of its working band is required to cover the 3.1~10.6GHz Higher gains, such as high resolution radar antennas for target tracking, are often 30dBi or even higher; smaller sizes, such as wireless terminal antennas, often need to arrange 6 pairs and above antennas in extremely limited space. At this point, antenna size needs to be reduced by a variety of antenna miniaturization techniques. In the process, some installation platforms have certain requirements for the aerodynamic performance of the antenna system. The designed antenna must be beneficial to the conformal installation to reduce the wind resistance. As a special antenna structure that is different from the traditional side shot antenna, the antenna can generate radiation at the end in a lower section and is beneficial to the conformal installation. On the other hand, the antenna is beneficial to the configuration of the antenna. At the end of the antenna which needs conformal design, its special installation environment makes the design of the antenna need to take into account the influence of metal surface and dielectric radome, all of which bring great challenges to the design of the antenna. At present, there are few related researches on the design of conformal end shooting array at home and abroad, but the conformal end shooting array plays a more and more important role in the fields of ultra wideband passive direction finding, phased array radar, anti radiation missile and so on. The design method and the related theory are of great significance. In this paper, a kind of ultra wideband end shooting antenna based on the gap is designed and designed. It has the characteristics of simple feeding structure, low profile and favorable for conformal installation. At the same time, the large metal column is used as a conformal installation platform for antenna radiation. The effect of sex is explored and the transmission characteristics of the electromagnetic wave are analyzed when the plane wave is incident in stratified medium. The basic theoretical basis is provided for the analysis of the influence of the dielectric radome to the antenna performance. The main research work and innovation points are as follows: first, it takes the gap as the basic radiation unit and is quasi non frequency variant according to the logarithmic periodic law. In order to improve the phenomenon of beam upwarping by prolonging the size of the front surface of the end of the slot, two, for the two-way radiation problem of the folded slot antenna, and the practical application. In the process, the harsh environment characteristics of the conformal installation on the metal carrier platform are needed. The differences and similarities between the slot antenna and the metal back cavity are compared and studied. It is concluded that the slot antenna loaded back cavity has better radiating performance than the loaded reflector, and the key of the metal back cavity is studied deeply. The influence mechanism of the parameters on the folded slot antenna provides a preliminary theoretical basis for the design of the next logarithmic periodic back cavity folded slot antenna. Three, the method of using the inverted structure and adding a dielectric layer above the radiant aperture is proposed to optimize the antenna performance so that it can achieve a good match and stability in the broadband (6~18GHz). End direction radiation. The simulation and measured results show that the antenna achieves stable end direction radiation in the whole 6~18GHz band, and the gain of the positive end shooting direction is above 4dBi. Four, a coplanar waveguide based on coupling principle, microstrip line conversion structure is proposed, which effectively realizes the broadband feed demand of the antenna designed in this paper. The transformation structure has the characteristics of good impedance matching and small insertion loss in 6~18GHz. Five, the difference between the radiation performance of the antenna when the antenna is used individually and conformal in the metal column is compared and analyzed. The influence of the metal carrier on the antenna performance is obtained. The transmission characteristics of the plane wave in the stratified medium are analyzed, and the analysis is made for the analysis. The dielectric radome in front of the antenna provides a theoretical basis for the effect of antenna performance. It provides guidance for the design of the end ejection conformal array. Through the above research, the ultra wideband end shooting antenna based on the slot is proposed and designed to be conformally installed on the metal carrier platform. The stable end radiation and the positive end ejection are realized in the 6~ 18GHz. The gain is above 4dBi and has a lower section. The overall profile of the antenna is only 11.1mm., and the analysis of the influence of the metal column and the dielectric radome on the antenna performance can effectively guide the design of the conformal end shooting array. The above research results provide a new idea for the broadband end shooting antenna design and can be well applied to the design of the antenna. UWB passive conformal direction finding array, UWB conformal phased array, missile borne end fire antenna, etc.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN820

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