涂覆球体的散射矩阵及极化分析

利用物理光学法及平面板块元法，通过场的Ｆｒａｎｚ表达式，对涂覆 散射阵进行了推导和计算，然后通过散射阵分析目标散场场的极化特性参数和最优极化，并给出了具体算体。     

有耗媒质中电磁场的近代解析解

本文给出了平面分层，柱面分层、球面分层、长球及旋转椭球等有耗媒质边界的近代解析解。介绍了求解有耗媒质内场及能量吸收特性的典型方法，并指出了各种方法的特点及应用条件。     

旋转微椭球体光散射的研究

采用了Eikonal近似方法对旋转微椭球体颗粒光散射进行了理论研究，并把旋转微椭球用其等效的球来近似，进而应用Mie散射理论对旋转微椭球体颗粒光散射进行数值计算，并对计算结果进行了分析。结果表明，旋转微椭球体颗粒散射光振幅分布与其位置(θo、θo)、离心率及入射光波长有关，并与其内、外切球的光散射情况接近。     

导弹头共形阵的射线寻迹及UTD参数计算

本文根据微分几何原理，导出了与导弹头并形的旋转抛物面上绕射场的UTD参数的计算公式。通过拟椭球积分得到了旋转抛物面上短程线的解析式，避免了数值方法射线寻迹的复杂性，同时简化了UTD参数的计算。这些公式是UTD法计算并形阵的辐射特性和耦合特性时所必需的。     

任意取向多个介质旋转椭球的散射场

本文提出了一种用于计算任意取向多个介质椭球电磁散射的混合方法.利用扩展边界条件(EBC)导出具有旋转轴对称单个椭球以球面波矢量函数为基底的T矩阵,结合球矢量波函数旋转定理和递推T矩阵方法,给出多个任意取向介质椭球的散射场.数值例子验证了该混合方法的计算精度和有效性.     

二维有耗介质目标重建的Newton迭代方法

本文给出了一种由已知的散射场数据重建二维非均匀有耗目标的复介电常数的迭代算法。由积分方程出发，利用点匹配技术导出了依赖于未知参数的解析逆散射公式。由此可以以解析的形式计算场量对未知参数的导数（Jacobian和Hessian矩阵）。本文采用Newton优化方法迭代求解逆散射问题，具有二次收敛特性。为了克服逆散射中解的不适定性，连续采用多个方向的TM波照射目标，并采集目标区域外的散射场数据，以及采用共轭梯度法（CGM）求解逆问题，数值结果表明了本文所提方法的可行性和灵活性。     

一种宽频带,近场馈电的机械扫描平面（圆盘）反射器天线

本文分析了一种宽频带，近场喇叭馈电的平面圆盘反射器机械扫描天线。天线的组成见图1。平面圆盘被处在近场区域中的喇叭照射．并绕着喇叭轴旋转使圆盘散射场形成的波瓣在水平面内扫描。采用矢量Kirchhoff公式计算由喇叭照射在圆盘表面引起的磁场，并应用物理光学方法计算圆盘产生的散射场，即圆盘的散射波瓣，其中还包括喇叭的直接辐射场。计算结果基本上与实测结果吻合。因此本文的方法可用于宽频带，机械扫描平面反射器天线的设计。     

二维有耗介质目标重建的Newtoin迭代方法

本文给出了一种由已知的散射场数据重建二线非均匀有耗目标的复介电常数的迭代算法。由积分方程出发，利用点匹配技术导出了依赖于未知参数的解析逆散射公式。由此可以以解析的形式计算场量对未知参数的导数（Jacobian和Hessian矩阵）。本文采用Newton优化方法迭代末解道散射问题，具有二次收敛特性。为了克服逆散射中解的不适定性，连续采用多个方向的TM波照射目标，并采集目标区域外的散射场数据，以及采用共轭梯度法（CGM）求解逆问题．数值结果表明了本文所提方法的可行性和灵活性。     

导体球涂覆各向异性铁氧体介质电磁散射的解析解

该文用球矢量波函数对各向异性铁氧体介质涂覆导体球的电磁散射解析解开展研究。各向异性铁氧体介质中电磁场的球矢量波函数解可表示成第一、二、三、四类球矢量波函数之和。根据球Bessel函数的性质,可以得出导体球涂覆各向异性铁氧体介质的球矢量波函数解析解。应用铁氧体与自由空间分界面上电磁场切向连续和在导体球面上切向电场等于零的边界条件以及球矢量波函数切向正交性质,可分别得出铁氧体介质中电磁场和散射场的展开系数。给出了平面波入射情况下的数值计算结果。该文的结果可应用于有关微波器件、天线以及目标特征的分析和计算。     

用时域积分方程法计算介质目标的电磁散射

本文应用时域积分方程法计算介质目标的散射场，并以球体和带球帽的圆柱体为例给出了沿轴向入射平面波的电磁散射结果，与实际测试结果非常一致，值得指出的是，虽然本文给出的介质目标具有平面对称性，但该方法适用于任意形状的目标。     

Scattering from a chirally coated DB elliptic cylinder

An exact analytic solution to the problem of scattering of a plane electromagnetic wave from a chirally coated elliptic cylinder defined by a DB boundary has been obtained, by expanding the different electromagnetic fields associated with the problem in terms of suitable elliptic vector wave functions and a set of expansion coefficients. The incident field expansion coefficients are known, but the expansion coefficients associated with the fields scattered outside the coated cylinder and the fields transmitted inside the coating are unknown. These unknown coefficients are obtained by imposing appropriate boundary conditions at the two boundaries. Results have been presented as normalized bistatic and backscattering widths for a variety of admittances, permeabilities, and permittivities of the chiral materials used for the coating, to show their effects on scattering from the chirally coated cylinder.     

Scattering by a conducting spheroidal object with dielectriccoating at axial incidence

An analytic solution of a plane electromagnetic wave scattering by coated prolate spheroidal bodies is obtained, for axial incidence, by expanding the incident and scattered fields in terms of prolate spheroidal vector wave functions. The unknown expansion coefficients are determined by an infinite system of equations derived using appropriate boundary conditions. To solve for the unknown coefficients, the system of equations is truncated by retaining only the first N equations in N unknowns, where N depends on the size of the body and the desired accuracy. Numerical results for the scattering cross section are presented to show the effect of different coatings on the magnitude of the scattered field     

Scattering of Gaussian Beam by a Conducting Spheroidal Particle with Confocal Dielectric Coating

An analytic solution to the scattering by a coated spheroidal particle, for arbitrary incidence of a Gaussian beam, is constructed by expanding the incident and scattered electromagnetic fields in terms of spheroidal vector wave functions. The unknown expansion coefficients are determined by a system of linear equations derived from the appropriate boundary conditions. Numerical results of the normalized differential scattering cross section of the conducting and coated spheroidal particle are evaluated, and the scattering characteristics are discussed concisely.     

Scattering by an infinite cylinder coated with an inhomogeneous and anisotropic plasma sheath

The problem of the interaction of an incidentHwave with an infinite conducting cylinder coated with an inhomogeneous and anisotropic plasma sheath is treated analytically. Numerical results for the farfield pattern of the scattered field as well as the backscattering cross sections are presented for various interesting ranges of the parameters involved. Detailed discussion of the effects of the impressed static magnetic field, the sheath thickness, and the density and profile of the plasma sheath on the scattered wave is also presented. A parabolic electron density profile is assumed.     

Two-Dimensional Scattering by a Conducting Elliptic Cylinder Coated With a Homogeneous Anisotropic Shell

A solution to the two-dimensional scattering properties of a conducting elliptic cylinder coated with a confocal homogeneous anisotropic elliptical shell is obtained. The transmitted field of the anisotropic shell is expressed as an integral equation based on waves with different wave numbers and different directions of propagation. The waves in all directions are represented as the eigenfunction expansion in elliptic coordinates in terms of Mathieu functions. In order to solve the nonorthogonality properties of Mathieu functions, Galerkin's method is applied and a matrix is required for the computation of unknown expansion coefficients of the scattered and transmitted fields. Only the transverse magnetic (TM) polarization is presented, while the transverse electric (TE) polarization can be obtained in the same way. Some numerical results are presented in graphical forms. The result is in agreement with that available as expected when a coated elliptic cylinder degenerates to the coated circular one.      

求解目标地波散射特性的方法研究

本文把求解半空间散射问题的FDTD技术与地波传播理论相结合，研究任意复杂目标的地波散特性。入射地波设置在FDTD计算区域中的总场边界上并在散射场输出边界面上提取散射近场数据，然后利用等效及镜像原理，计算无地波衰减时的远区散射场，通过引入地波衰减因子，把该远区散射场转换为远区地波散射场，文中给出了方法验证例子以及一个较复杂目标的单站RCS计算结果。     

Application of the Rotating Angle Parabolic Equation Method for the Solution of Scattering Problems

In this paper the rotating angle parabolic equation method (PEM) is presented for the solution of scattering problems. Separate spectral domains for the incident and scattered fields are obtained and their sum is substituted into the wave equation. Considering the satisfaction of wave equation by the incident and scattered fields, the solution of wave equation changes into the solution of two separate parabolic equations for the incident and scattered fields. The paper continues with the development of an algorithm for the determination of back scattered fields from knife edges and scattered fields from the slope and slope discontinuities. It will be seen that the results of the proposed algorithm agree with those of other methods for the solution of aforementioned problems.

基于散射理论的电磁波正演研究

电磁波在雷达探测、导航定位、通信中都有较为广泛的应用。发射电磁波,遇到目标之后被反射回来,通过处理回波信息从而得到目标的距离、速度、角度等信息,这是最常用到的一种处理方式。基于散射波目标探测方法是当电磁波传播到目标界面时,会以目标反射界面上各点作为激发源继续向外传播,通过接收并处理返回的散射波,从而获取目标的信息。在麦克斯韦(Maxwell)方程组的基础上,基于散射理论,推导并给出了电磁波在频率域的散射波表达式。 这种基于散射波进行目标探测的方法,在无源定位、相隔较近的机动目标识别、小目标识别等方面有一定的优势。     

Scattering from a coated perfect electromagnetic conducting elliptic cylinder

An exact analytic solution is presented to the problem of scattering from a coated perfect electromagnetic conducting (PEMC) elliptic cylinder, when it is illuminated by a plane wave as well as a line source. The problem is formulated by expanding the various fields in terms of appropriate angular and radial Mathieu functions and a set of expansion coefficients. The expansion coefficients associated with the incident fields are known, but those associated with the scattered fields and the fields within the coating are unknown. Imposing boundary conditions at the surface of the PEMC elliptic cylinder and the surface of the coating, enables the determination of the unknown expansion coefficients. Results are presented in the form of normalized scattering widths for elliptic cylinders of various sizes, PEMC admittances, and different coatings, to show the effects of these on scattering.     

A Modulated Scattering Technique for Measurement of Field Distributions

Electric field distributions can be measured accurately by passing a short metal dipole through the field and recording the wave scattered by the dipole. Ordinarily the method is difficult to use since the scattered signal is small, critical tuning adjustments are required, and careful attention to stability is necessary. However, by placing a nonlinear impedance at the center of the dipole and applying an audio voltage though slightly conducting threads, the scattered wave can be modulated. This makes it possible to relax the tuning and stability requirements and at the same time to increase the sensitivity of the measurements.