Rayleigh Scattering for An Electromagnetic Anisotropic Medium Sphere

Based on the scales theory of electromagnetic waves, the analytical expression of electrical fields inside an anisotropic medium sphere is studied. Differential scattering cross section and radar cross section （RCS） for an anisotropic spherical target are presented. The correctness of the obtained results is tested. The simulation results show that the scattering of an anisotropic sphere has the property of a dipole radiation under the condition of Rayleigh scattering. The larger the dielectric constant is, the stronger the dipole scattering is. Anisotropy in magnetism only has an effect on differential RCS. These results provide a theoretical base for the identification of anisotropic targets.     

脉冲激光入射下介质薄膜双频互相关散射截面及功率展宽

 结合特殊的镀金聚酯薄膜表面的粗糙度和半球反射率,依据基尔霍夫近似及粗糙面脉冲散射互相关函数,数值计算了脉冲激光（1.06 μm）在不同入射角照射下该材料薄膜双频互相关散射截面随相干带宽频差和散射角的变化情况。并给出δ脉冲和高斯脉冲波入射下,其散射功率随时间和散射角的波形分布。计算结果表明：该薄膜材料激光双频互相关散射截面在镜反射方向有最大的散射峰值,在非镜反射方向上,其散射值随相干带宽频差的增大迅速减小,当窄脉冲垂直入射时,粗糙面散射功率展宽现象明显。     

椭圆柱体对任意入射极化的电磁波的散射

基于电磁场的多尺度变换理论,得到了以导体椭圆柱为例的电磁波任意极化,任意垂直入射到目标上的散射场的解析式.将所得结果应用于计算圆柱目标的散射场,结果与文献完全一致.对椭圆柱体的散射宽度随入射波方位角,电磁波频率以及目标尺寸的变化进行了仿真.结果表明,在垂直于电磁波的方向上观测时,椭圆柱的垂直尺寸对散射有较大的影响,电磁波水平极化时散射最强.所用算法适用于介质椭圆柱等目标的散射特性研究,所得结果为目标尺寸、形状遥感电磁测量等实际应用提供了理论依据.     

Scattering of particles in wave beam based on series expansion

Based on the orthogonalities of the vector wave functions, the expressions of scattering fields are developed as the particle in the zero order field and in the first order fields of x, y, and z, respectively. A general relation between the expansion coefficients of scattering field and incident field is presented. Taking the elliptical beam for example, the scattering property of a particle in beam is investigated. After analyzing the effects of the beam waist, irradiating distance, etc. on scattering property, the validity of the proposed algorithm is demonstrated. Results show that the beam waist may improve the particle identification property and the particle has a strong scattering both in the forward direction and in the backward direction. The method proposed is simple and is a new way of researching the scattering from particles in electromagnetic beams.     

双向隐形传态方案及安全性分析

基于位函数的引入与介质参量无关,将各向异性目标内外的电场展为级数形式,得到了任意各向异性目标n阶散射场、目标内场的递推表达式,给出了介电常量张量的变换关系,在平面波任意入射的条件下,并给出了传播单位矢量与极化单位矢量的一般关系.以磁化冷等离子体为例,给出了一阶散射场的具体表达式,并对二阶散射场引起的误差进行了评估.在THz波段和光波段,对所得结果进行了部分仿真.结果表明:微分散射对电波频率和极化状态等因素的影响较为敏感,介电常量张量的非对角元素对散射的影响不大,当波长与目标尺寸一定时,仿真结果不仅适用于THz波段,对其它波段也成立.     

The scale-transformation of electromagnetic theory and its applications

The scale-transformation of electromagnetic theory is investigated in detail based on the form of Maxwell equations in scale-transformation being unchanged in different coordinate systems. The relations of electromagnetic parameters in a rectangular coordinate system and in a spherical coordinate system are presented respectively. The scale-transformation invariants for electromagnetic field are derived and their physical meaning is also presented. It is indicated by simulation that the electromagnetic waves located in medium can be considered to be isotropic due to the fact that the size of propagating vector affected by the scale factors and observing azimuth is on a size of 10^-9, which provides a new approach for investigating the electromagnetic characteristics of ellipsoidal targets.     

磁化冷等离子体球的太赫兹散射特性

基于位函数的引入与介质参量无关,将各向异性目标内外的电场展为级数形式,得到了任意各向异性目标n阶散射场、目标内场的递推表达式,给出了介电常量张量的变换关系,在平面波任意入射的条件下,并给出了传播单位矢量与极化单位矢量的一般关系.以磁化冷等离子体为例,给出了一阶散射场的具体表达式,并对二阶散射场引起的误差进行了评估.在THz波段和光波段,对所得结果进行了部分仿真.结果表明:微分散射对电波频率和极化状态等因素的影响较为敏感,介电常量张量的非对角元素对散射的影响不大,当波长与目标尺寸一定时,仿真结果不仅适用于THz波段,对其它波段也成立.     

高速运动分层介质界面上的时间平均能流密度

利用坐标变换和高速运动介质界面上平面电磁波入射、反射和透射电场、磁场之间的关系,详细讨论了当介质界面运动时入射、反射和透射时间平均能流密度的变化规律.     

介质球的各向异性瑞利散射

基于电磁场的多尺度理论,研究了各向异性介质球内、外电场的规律,导出了各向异性目标散射场的表达式,得到了各向异性介质目标散射振幅、散射截面等的解析表达式,并对其正确性进行了检验.仿真结果表明:各向异性介质球的散射具有偶极辐射的特点,介电常量越大,产生的偶极矩也愈大,散射也越强.其结果可为各向异性目标监测、各向异性光散射研究等提供理论支持.     

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给出了不同坐标系中介质参数张量的变换,得到了磁化冷等离子体球电场的表达式,得出了任意各向异性目标散射场的表达式,研究了磁化冷等离子体球的微分散射截面、散射截面等的函数关系,仿真结果与有关文献一致,表明了本算法的有效性,从而为各向异性目标识别等提供理论支持。