频率选择结构机载天线罩电信设计与实现

发布时间：2018-03-09 00:23

本文选题：机载天线罩　切入点：频率选择表面　出处：《山东大学》2014年硕士论文　论文类型：学位论文

【摘要】：频率选择表面(frequency selective surfaces,简称FSS)是指在一种沿一维或二维方向上周期性排布的金属结构,它本身不吸收电磁能量,却能有效控制电磁波的传输和反射特性,实质是一种空间滤波器。其在科学和工程等领域具有重要的应用价值,日益受到国内外研究人员的关注。机载天线罩是机载雷达天线的保护装置,作为飞机机体的一部分,要求维持气动外形、承受飞行载荷、耐受飞行环境,同时作为雷达天线的电磁窗口,要求保证内部天线的正常工作。频率选择结构机载天线罩是在满足上述功能的基础上,通过在指定频段上呈现“全金属”特性,屏蔽内部天线系统的强散射,结合天线罩本身的流线型外形,满足飞机整体的隐身需求。本文对频率选择结构机载天线罩的电信设计与实现技术进行了研究。通过对不同类型频率选择表面(FSS)单元的尺寸、周期排布、层数等多参数下的频响特性的形成机理、频响特性和分析方法开展研究,找到适用于机载天线罩的具有较好的入射角和极化稳定性的FSS单元。开展频选结构天线罩的基本设计要素研究,提出了实现大入射角、恒定带宽和稳定极化的设计准则和抑制栅瓣的方法。针对机载天线罩的流线型外形特性和电性能指标要求,首先对天线罩的入射角分布和极化特性进行分析,通过FSS与介质加载结构的结合方式的研究,确定了双层FSS/A型夹层介质加载结构,选用介电性能和力学性能优良的复合材料,采用基于Floquet模式匹配法的有限元电磁场仿真分析软件对FSS等效平板的频响特性进行了设计仿真优化,并将仿真结果与测试结果进行了比对,两者具有较好的吻合性。采用FEM/PO混合算法软件对频选结构天线罩的通带传输和方向图特性以及阻带截止特性进行了仿真计算,结果表明设计的频选结构天线罩具有优良的通带高传输和低方向图畸变以及阻带高截止特性,在阻带内实现了对天线系统的隐身效果。本文中使用的频选结构天线罩高低频混合算法软件兼顾了计算效率和计算精度要求,具有极高的工程使用价值。本文主要开展以下研究工作： 1、研究周期性FSS的分析方法,对不同类型频率选择表面单元的谐振频率、频率响应、带宽特性进行分析比较,找出适合于机载天线罩的FSS单元形式、栅格排布方式和层数等参数； 2、开展频率选择结构天线罩基本设计要素研究,提出实现大入射角、恒定带宽和稳定极化的设计准则和抑制栅瓣的方法。 3、研究频率选择结构天线罩的设计流程,利用基于有限元法和物理光学法的混合仿真分析方法对频率选择结构天线罩的电性能进行仿真计算。
[Abstract]:Frequency selective surfaces (FSS) is a metal structure arranged periodically along one or two dimensional direction. It does not absorb electromagnetic energy, but it can effectively control the transmission and reflection characteristics of electromagnetic waves. Essential is a kind of space filter, which has important application value in science and engineering, and has been paid more and more attention by researchers at home and abroad. The airborne radome is the protective device of the airborne radar antenna. As a part of the aircraft body, it is required to maintain the aerodynamic shape, to withstand the flight load, to withstand the flight environment, and to act as the electromagnetic window of the radar antenna. It is necessary to ensure the normal operation of the internal antenna. On the basis of satisfying the above functions, the airborne radome with frequency selective structure can shield the strong scattering from the internal antenna system by presenting the "all metal" characteristic on the specified frequency band. Combined with the streamline shape of the radome itself, it can meet the stealth requirements of the aircraft as a whole. In this paper, the telecommunication design and implementation technology of frequency selective structure airborne radome is studied. The formation mechanism of frequency response characteristics of different types of frequency selective surface FSSs, such as size, periodic arrangement, number of layers and so on, is studied. The frequency response characteristics and analysis methods are studied, and the FSS elements with good incident angle and polarization stability are found for airborne radome. The basic design elements of frequency-selective structure radome are studied, and the realization of large incidence angle is proposed. The design criteria of constant bandwidth and stable polarization and the method of suppressing the gate lobe. According to the streamline shape characteristics and electrical performance requirements of the airborne radome, the incident angle distribution and polarization characteristics of the radome are analyzed. Through the study of the combination of FSS and dielectric loading structure, the double layer FSS/A sandwich dielectric loading structure was determined. The composite with excellent dielectric and mechanical properties was selected. The frequency response characteristics of FSS equivalent plate are simulated and optimized by using the finite element electromagnetic field simulation software based on Floquet pattern matching method, and the simulation results are compared with the test results. The FEM/PO hybrid algorithm software is used to simulate the passband transmission, pattern characteristics and stopband cut-off characteristics of the frequency-selective structure radome. The results show that the designed frequency selective structure radome has excellent passband high transmission, low pattern distortion and stopband high cut-off characteristics. The stealthy effect of antenna system is realized in the stopband. The high and low frequency hybrid algorithm software of frequency selective structure radome is used in this paper, which takes into account the requirements of calculation efficiency and accuracy, and has high engineering application value. This paper mainly carries out the following research work:. 1. The analysis method of periodic FSS is studied. The resonant frequency, frequency response and bandwidth characteristics of different types of frequency selective surface elements are analyzed and compared, and the FSS element forms suitable for airborne radome are found out. Grid layout mode and layer number and other parameters; 2. The basic design elements of frequency selective structure radome are studied, and the design criteria of large incident angle, constant bandwidth and stable polarization and the method of suppressing gate lobe are proposed. 3. The design flow of frequency selective structure radome is studied, and the electric performance of frequency selective structure radome is simulated by the hybrid simulation analysis method based on finite element method and physical optics method.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN820.81

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