【作者】 官正涛；

【导师】 杨儒贵；

【作者基本信息】 西南交通大学 ， 电磁场与微波技术， 2004， 硕士

【摘要】 天线罩是用来保护天线的一种介质外壳，使天线避免在各种恶劣环境条件下可能造成的损坏。尽管天线罩可完成有用的天线保护功能，但它的存在又必然会影响到天线的特性，降低相应电子系统的效能。到目前为止，天线罩的材料仅限于电介质材料。天线罩引起的很多问题都是由于电介质材料只具有电特性，而不具有磁特性造成的。本文研究的新型有机磁性材料弥补了单纯电介质材料的不足。 本文研究有机磁性材料天线罩的传输特性，天线罩电气特性与有机磁性材料电参数之间的关系，以便优化磁性材料电参数。首先，以直接射线法分析平面波在有机磁性媒质与空气的界面上的反射特性，为后续天线罩的电气特性分析提供理论基础。然后引入多次反射概念讨论单层磁性平板天线罩的传输特性，进一步了解电磁波与磁性介质板的相互作用机理。对于均匀且各向同性的介质平板，其两侧的电磁场关系与传输线的转移矩阵方程形式一致，故可把均匀介质平板当作一段均匀的传输线。因此，可以用四端口网络理论来分析多层磁性平板天线罩的传输特性，根据网络理论得出多层平板天线罩的转移矩阵是各层平板转移矩阵的级联。对于曲面天线罩，本文采用复射线近轴近似法进行分析，主要讨论单层圆柱面磁性材料天线罩的电气特性。计算结果表明，当磁性材料的相对介电常数与相对磁导率相等时，天线罩具有最佳的传输性能。 课题的研究在天线罩领域中具有一定的开拓作用，为磁性材料天线罩的研究提供了理论基础。更多还原

【Abstract】 Radome, which is a kind of dielectric shell, is used to protect antenna and avoid its.damage from the possibly worst conditions. Though radome has the advantage of protecting antenna, it must deteriorate the radiate performance of antenna and debase the efficient power of electric system with radome. So far the material of radome limits only in the use of dielectric material. Many problems caused by radome are the result of asymmetric electric parameters of dielectric material, which means it has no magnetic character but electric one. Fortunately there is a kind of new organic magnetic material discussed in the paper, which can make up the disadvantage of dielectric material.In the thesis, the transmission performance of organic magnetic material radome is discussed, and the analysis of relation between the electric performance of radome and the electric parameters of organic magnetic material aims at optimizing the later. As the foundation of analysis of electric performance of organic magnetic material radome, the reflection performance of plane waves being incident on a plane boundary between organic magnetic medium and air is firstly investigated with the help of ray tracing method. And then the concept of multiple reflections is introduced to discuss the transmission performance of flat organic magnetic material radome so as to clarify the mechanism of plane wave propagation through magnetic dielectric sheet. For a homogeneous and isotropic magnetic sheet, the relation between electric and magnetic field on the sides of it has the same form with the’transfer matrix equation of transmission 1 ine. As a result, a homogeneous dielectric sheet can be looked upon as a uniform transmission line. Therefore, the transmission performance of multilayer plane organic magnetic material radome can be analyzed by use of four-port network theorem, that is, on the basis of network theorem, the transfer matrix of multi layer plane radome is the resultof cascade connection of transfer matrixes of each layer. As far as curved radome is concerned, paraxial approximation analysis of complex ray method is employed in the paper, and the electric performance of single-layer cylindrical organic magnetic material radome is discussed mainly. Numerical results showed that the radome had the most optimized transmission performance if the relative permittivity of organic magnetic material equals to the relative permeability.Therefore, this research will play a pioneer role in the field of radome and provide the foundation for theoretical study of the organic magnetic material radome.更多还原