宽带电阻型FSS吸波材料设计与研究

发布时间：2018-02-12 17:27

本文关键词： 频率选择表面电阻膜传输线理论智能优化算法　出处：《南京大学》2015年硕士论文　论文类型：学位论文

【摘要】：吸波材料最早应用于军事领域,用以实现武器系统的隐身,现已扩展到电磁兼容、电磁污染防护、通讯系统、国家安全等多个应用领域。研究和开发高性能的吸波材料已经成为材料研究领域的一个重要课题。吸波材料的实现技术多种多样,频率选择表面是其中最常用的现技术之一。它是一种周期阵列结构,一般是由完全相同的单元沿一维或者二维的方向周期性排列而构成的单层或多层无限大平面结构。近年来,FSS已经广泛应用在微波频段到光波频段吸波材料的研制,在雷达探测、飞行器隐身等国防领域中彰显其作用。周期性FSS结构还表现出实现许多天然材料所不具备的性能,大大拓展了FSS的应用场合。本文研究了一种基于电阻型FSS的轻质超宽频带的电磁波吸波体的设计、制备以及吸波机制,实现了在5-21GHz之间对入射电磁波有着极强的吸收。本文的主要研究内容及贡献主要包括：一、研究了FSS电阻膜的物理性质,用电子显微镜观察了电阻膜的表面形貌特征；用高频终端开路法测量了电阻膜的反射系数,由此反演出FSS电阻膜的高频电导率,并将此结果与传输透射法反演出的电导率作比较。二、基于电阻型FSS设计了轻质宽带吸波材料,研究介质基板的介电常数、厚度与电阻膜的方块电阻等因素对吸波材料吸波性能的影响。采用FSS吸波材料的传输线等效模型,结合场模式分析,探究了该吸波材料具有宽带吸收的原因。在此基础上,提出了用FSS的等效网络替代等效电路模型,更加正确地反映了吸波材料的频率特性。从仿真和实验证明了该材料的吸波性能具有极化不敏感和大入射角度的特点。三、利用智能算法对吸波材料进行了优化设计,通过改进优化策略、设计不同的自适应度函数设计出了具有宽带和低剖面的轻质吸波材料,其-10dB带宽达到6.25-25.30GHz,而厚度仅为3.92mm。对设计结果进行了实验验证,其结果和理论设计相吻合,验证了设计的有效性。四、在上述的理论分析和仿真计算的基础上,我们进行了一系列的实验研究工作。我们利用丝网印刷技术制作了FSS电阻膜,利用弓形架测试系统测量了不同样品的反射性能,并对测量结果与理论分析结构进行对比分析。实验结果表明,该FSS材料具有大入射角、极化不敏感、宽频带的特性,满足设计要求。
[Abstract]:The absorbing material was first used in the military field to realize the stealth of the weapon system. Now it has been extended to electromagnetic compatibility, electromagnetic pollution protection, communication system, The research and development of high performance absorbing materials has become an important subject in the field of material research. The frequency selective surface is one of the most commonly used technologies. It is a periodic array structure. Generally speaking, it is a single layer or multilayer infinite plane structure composed of exactly the same elements arranged periodically along one or two dimensional direction. In recent years, FSS has been widely used in the development of absorbing materials in the microwave frequency band to the optical frequency band, and in radar detection. Aircraft stealth and other areas of national defense show its role. The periodic FSS structure also shows the performance that many natural materials do not have. The application of FSS is greatly expanded. In this paper, the design, preparation and mechanism of a lightweight ultra-wideband electromagnetic wave absorber based on resistive FSS are studied. The main contents and contributions of this paper are as follows: firstly, the physical properties of FSS resistor film are studied, and the surface morphology of the film is observed by electron microscope; The reflection coefficient of the resistance film is measured by using the high frequency terminal open circuit method, and the high frequency conductivity of the FSS resistance film is inversed. The results are compared with those obtained by the transmission and transmission method. Based on resistive FSS, the light broadband absorbing material is designed. The influence of dielectric constant of dielectric substrate, thickness and square resistance of resistor film on the absorbing property of absorbing material is studied. The equivalent transmission line model of FSS absorbing material is adopted. Based on the field mode analysis, the reason why the absorbing material has broadband absorption is discussed. On the basis of this, the equivalent network of FSS is proposed to replace the equivalent circuit model. The frequency characteristic of the absorbing material is more accurately reflected. The simulation and experiment show that the absorbing property of the material has the characteristics of polarization insensitivity and high incidence angle. Thirdly, the optimum design of the absorbing material is carried out by using the intelligent algorithm. By improving the optimization strategy, different adaptive degree functions are designed to design light absorbing materials with wide band and low profile. The bandwidth of -10dB is 6.25-25.30GHz and the thickness is only 3.92mm. the experimental results are verified. The results agree with the theoretical design and verify the effectiveness of the design. Fourthly, based on the above theoretical analysis and simulation, we have carried out a series of experimental studies. We have made the FSS resistor film by screen printing technology. The reflectivity of different samples was measured by using a bow frame test system, and the measured results were compared with the theoretical analysis structure. The experimental results show that the FSS material has the characteristics of large incident angle, insensitive polarization and wide frequency band. Meet the design requirements.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB34

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