【作者】 杨梅；

【导师】 吴先良；

【作者基本信息】 安徽大学 ， 电磁场与微波技术， 2011， 硕士

【摘要】 目前,计算电磁学经研究具有非常广泛的理论和实际的价值,并已充斥到电磁学的多个方面的研究领域。电磁学中的一个重要的研究领域是电磁散射的问题。比如,利用飞机这个散射体通过散射传回来的电磁波,来使雷达对飞机进行目标跟踪、方向定位和目标识别。本文首先介绍了高阶矩量法的基本原理和应用,其次利用高阶矩量法,并结合快速(FMA)算法,深入研究电大尺寸物体的电磁散射特性,最后将高阶基函数结合旋转对称体来充分验证该高阶矩量算法的精确性、高效性和快速性。本文是根据最佳一致逼近理论的数学基础来提出新型的高阶基函数方法,将未知电流以此高阶基函数进行展开,先后求解电流的电场积分方程(EFIE)公式、磁场积分方程(MFIE)公式和混合场积分方程(CFIE)公式。此高阶基函数可以在比较少的未知量数目下获得较高的精度,计算复杂度将大大地降低,而且对于计算内存也将节约许多。本文通过对多个形状的目标散射体进行计算仿真分析,充分表明了所提高阶算法和计算结果的有效性。并将该算法结合FMA,进行求解电大尺寸物体的电磁散射问题。此高阶矩量法不仅应用于二维电磁散射问题,也应用于理想金属旋转对称体散射问题。解决旋转对称体问题,首先将未知电流进行展开,分别展开成φ的傅里叶级数形式和t的切向分段函数形式,然后将电流展开为高阶基函数形式,所求的解结合误差来进行分析,充分验证了所提算法的有效性,并且得到满意的结果。更多还原

【Abstract】 Recently, computational electromagnetics with a wide range of applications, it has penetrated into every field of electromagnetism, in which electromagnetic scattering problem is an important field. For example, the scattering of radar echoes using aircraft locating, track aircraft and target recognition.Firstly, this thesis introduces the basic principles and applications of high-order method of moments, secondly, the high-order method of moments combined with fast multipole Method, further introduces scattering analysis of electrically large conductors, and finally will extend to electromagnetic scattering from perfectly conducting bodies of revolution. By doing these work, it will fully verify the accuracy, efficiency and rapidity of high-order method of moments. Based on the theory of the best uniform approximation, a new high-order basis function is constructed. Firstly, the unknown current will be expanded by this new high-order basis functions, then further it will solve the electric field integral equation (EFIE), the magnetic field integral equation (MFIE) and the combined field integral equation (CFIE). It is shown that the high-order method of moments has higher precision with lower discretization than the conventional method of moments, and effectively reduces the computational complexity and save computer memory. According to the different shape scattering body, simulation validates the effectiveness of the proposed algorithm and procedures. Further the fast multipole Method is combined with this algorithm to solve the scattering problems of electrically large conductors.The high-order method of moments will be applied to two-dimensional electromagnetic scattering problems and the problems of electromagnetic scattering from perfectly conducting bodies of revolution. Because bodies of revolution has rotational symmetry, the unknown equivalent currents will be expanded in Fourier series inφand sub sectional in t, and the currents will be expanded by high-order basis functions. the solutions obtained combined with error analysis verify the validity of the proposed algorithm and obtain satisfactory results.更多还原