低剖面双圆极化阵列天线研究

发布时间：2018-01-09 09:32

本文关键词：低剖面双圆极化阵列天线研究　出处：《东南大学》2017年硕士论文　论文类型：学位论文

【摘要】：自上世纪五十年代合成孔径雷达(SAR)出现以来,其发展受到广泛关注,SAR最早应用于军事侦查,但其高分辨率及良好的成像质量使之在资源勘探、精密导航、气象观测和遥感等诸多领域成功应用,有着广阔的发展前景及研究意义。现代SAR往多方向发展,多参数SAR的不同极化方式能显著改善信号和图像的详细性、可靠性;机载星载SAR则对天线的小型化提出了要求。圆极化天线与线极化相比,可探测出目标更多的细节信息,并且,低剖面天线具有重量轻、成本低等特点,尤其是对大型天线和阵列天线的低剖面化,可以大幅度降低天线有效载荷重量和空间的占用。因此,本文着重研究具有低剖面、圆极化特点的天线。论文工作主要包含以下几个方面:(1)设计了一款背腔结构的贴片天线,采用容性耦合馈电方式展宽带宽,以双分支线耦合器产生幅度相等、相位相差90°的激励,使两正交线极化波合成为圆极化波,通过切换耦合器的输入端口,可实现左旋、右旋圆极化的切换。天线剖面仅0.1λ,为提高阵列的圆极化性能,采用旋转组阵的方式构成子阵,抵消物理结构上的不对称性,子阵实测部分结果符合仿真设计,分析了不符合仿真部分的原因。为实现低副瓣的要求,采用Taylor分布幅度加权法,完成了2×8线阵及6×6平面阵的仿真分析。(2)基于高阻抗表面的周期性结构,设计了一款低剖面微带天线,采用改进的正交偶极子结构,以及双分支线耦合器,形成圆极化,同样可实现左旋、右旋圆极化的切换,馈电采用空气桥结构。HIS模拟PMC,作为天线反射面,以降低剖面。2×2子阵及2×8线阵采用顺次旋转组阵的方式,提高阵列圆极化性能。(3)基于北斗卫星导航系统的关键频点设计了一款多频段天线,覆盖B1、B2、B3三个频点,采用改进的正交偶极子结构,实现左旋圆极化。推导了已知有源S参数,前端接理想电桥时电桥的回波损耗及隔离度公式。为方便确定来波方向,用以定位,采用六边形阵列的形式,仿真分析了阵列性能。(4)基于已确定的5G实验频段,设计了一款空间全覆盖的高隔离度天线,以3D打印的正十二面体为载体,在十一个面上安装天线,同时需保证单元间较高的隔离度,实测结果基本符合仿真。
[Abstract]:Since the appearance of synthetic Aperture Radar (SAR) in -50s, its development has been widely concerned about its application in military reconnaissance, but its high resolution and good imaging quality make it in resource exploration. Precision navigation, meteorological observation, remote sensing and many other fields have been successfully applied, which has broad development prospects and research significance. Modern SAR is developing in many directions. The different polarization modes of multi-parameter SAR can significantly improve the detail and reliability of the signal and image. Airborne spaceborne SAR requires the miniaturization of antenna. Compared with linear polarization, circular polarization antenna can detect more details of target, and low profile antenna has the characteristics of light weight, low cost and so on. Especially the low profile of large antenna and array antenna can greatly reduce the payload weight and space occupation. The main work of this paper includes the following aspects: 1) A patch antenna with a back cavity structure is designed, and the bandwidth is broadened by capacitive coupling feed. With the excitation of equal amplitude and 90 掳phase difference produced by double branched line coupler, the two orthogonal linear polarization waves are synthesized into circular polarization waves. By switching the input ports of the coupler, the left-handed wave can be realized. The antenna profile is only 0.1 位. In order to improve the circular polarization performance of the array, the rotation array is used to form a subarray to counteract the asymmetry in the physical structure. The experimental results of the sub-array are in accordance with the simulation design, and the reasons for the failure are analyzed. In order to realize the requirement of low sidelobe, the Taylor distribution amplitude weighting method is adopted. The simulation analysis of 2 脳 8 linear array and 6 脳 6 plane array is completed. Based on the periodic structure of high impedance surface, a low profile microstrip antenna is designed, which adopts an improved orthogonal dipole structure. And the double branch line coupler, forming circular polarization, can also achieve left-handed and right-handed circular polarization switching. The air bridge structure. His is used to simulate PMCs as the reflector of the antenna. A multi-band antenna is designed based on the key frequency points of Beidou satellite navigation system by decreasing the section .2 脳 2 subarray and 2 脳 8 linear array by using the sequential rotation array to improve the circular polarization performance of the array. The left-handed circular polarization is realized by using an improved orthogonal dipole structure covering three frequency points of B1OB2OB3. The known active S parameters are derived. The formula of echo loss and isolation degree of the bridge when the front end is connected to the ideal bridge. In order to determine the direction of the incoming wave and to locate it, the hexagonal array is adopted. Based on the determined 5G experimental frequency band, a high isolation antenna with full space coverage is designed. The antenna is installed on 11 planes using 12 planes printed in 3D as the carrier. At the same time, it is necessary to ensure high isolation between the units, and the measured results are basically in accordance with the simulation.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN957.2

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