旋转体目标散射远场的快速计算

Fast calculation of the far-field scattering from the rotationally symmetric object

提出了一种基于互易定理的快速计算旋转体目标散射远场的方法,该方法利用每个模式下表面等效电磁流的指数分布特性和散射体的结构特性,推导出了方位角积分的解析表达式,从而将二重积分降为易于计算的一重弧长积分.对一个平面波照射的介质球的仿真结果表明,在同样的离散条件和计算机条件下,若采用30点高斯积分处理方位角积分,计算远场散射需要212 s,而采用本方法仅需要不到1 s.

When the electromagnetic scattering property of the body of revolution object is to be analyzed,the mode decomposition technique is usually adopted to alleviate the computational burden.The surface equivalent electric and magnetic currents calculated by this approach are made up of many mode components,so too much computing time will be spent if the far-field is calculated directly by integral operation due to the oscillation of the integrand.Based on the reciprocity theorem,this paper presents a fast calculation method of the far-field scattering from the rotationally symmetric object.By taking advantage of the exponential distribution property of the surface equivalent currents under each mode and the structural property,we deduce the analytical expressions for the integral with respect to the azimuthal angle,and thus the two-dimensional integral is reduced to the easily computed one-dimensional arc-length integral.Simulation results for a dielectric sphere irradiated by the plane wave indicate that it will take 212 seconds to calculate the far-field scattering if the 30-point Gaussian integration is used,while only less than 1 second is needed by our presented method under the same discreteness and computer hardware.