椭圆柱体对电磁波散射的系统辨识模型  

System Identification Model of ScatteringElectromagnetic Field for An Ellipsoid

作　　者：李应乐[1] 黄际英[2] 

机构地区：[1]西安电子科技大学理学院,273信箱西安710071 [2]咸阳师范学院科研处

出　　处：《四川大学学报（自然科学版）》2004年第6期1201-1206,共6页Journal of Sichuan University(Natural Science Edition)

基　　金：国家自然科学基金(60171010);陕西省教育厅专项基金(03JK070)

摘　　要：作者利用圆柱体的散射场逼近椭圆柱体对电磁波的散射,建立了椭圆柱体散射的系统模型,分析了模型的物理意义,提出了进一步改善计算精度的方法;在毫米波段对模型所得结果进行了仿真并和圆柱体的散射场进行了对比.结果表明:当电磁波沿椭圆柱体的轴极化时,散射场主要是由平行于该轴的偶极子产生的,当椭圆柱体的大小和波长相差甚远时,椭圆柱体的散射截面小于同尺寸圆柱体的散射截面.当目标大小与波长可比拟时,椭圆柱的长短轴显著地影响着散射截面,与入射波的极化状态有关.绕射场的增强使得椭圆柱的前向表面电流大于圆柱的表面电流;当入射场垂直椭圆柱体的轴极化时,对于较大的椭圆柱目标而言,后向面电流和圆柱体的后向电流相差不大,但前向面电流与圆柱体的面电流相差较大,甚至相位相反.The system model of scattering electromagnetic field for an ellipsoid is constructed utilizing the scattering field of a cylinder to approach the scattering field induced by an ellipsoid. The physical significance of the model and method of further improving its accuracy in computation are presented. Simulations of the incoming results in millimeter wave band are made and compared with that of a cylinder. Results show: the scattering field for an ellipsoid is mainly radiated by the dipoles parallel to the ellipsoid' axis as the incident wave polarized in the axis, the differential scattering section of the ellipsoid is smaller than that of the cylinder when there is a big difference between the size for an ellipsoid and that for a cylinder, the D.S.S. is influenced greatly by both axis of ellipsoid an relative to polarization of incident wave as the axis is comparable to the operating wave-length. The forth electric current on ellipsoid' surface is bigger than that on a cylinder which is caused by the enhancement of circumambulate field. As the incident wave polarized vertical to the ellipsoid' axis, there is no large difference between the back electric current and that of cylinder, however, there exists a large difference in forth surface electric current and even exists a difference of πin phase.

关 键 词：椭圆柱体 电磁波散射 系统辨识 毫米波 

分 类 号：O451[理学—无线电物理]