变型共面波导的保角变换分析

本文采用精确和近似保角变换技术分析了四种结构变型的共面波导的特性，导出了它们的等效介电常数和特性阻抗的封闭表达式，并对其中一种结构的特性参量进行了近似计算。这些公式和结果对设计变型共面波导是有用的。     

变型共面波异的保角变换分析

本文采用精确和近似保角变换技术分析了四种结构变型的共面波导的特性，导出了它们的等效介电常数和特性阻抗的封闭表达式，并对其中一种结构的特性参量进行了近似计算。这些公式和结果对设计变型共面波导是有用的。     

椭圆函数变换的一个应用

本文利用椭圆函数变换t=sn(u jv,k)中v=K′(k)/2的特殊性,首先导出了同轴带状线的严格解;而后通过研究垂直带状线和普通带状线的中值等位线与椭圆的差异得到了平行板间椭圆柱问题及外椭圆内带问题的近似解。这些近似解比已有的解要简单得多且有相当的精度。     

平面镜像法与有源保角变换

本文把镜像法与复保角变换有机地结合起来。指出对于实际中的一大类问题,只须采用平面镜像做基本模型,而对复杂形状作有源保角变换,就可以归结为平面镜像。特别有兴趣的是变换后的求解区域可以允许存在原问题∞处的镜像电荷,从而突破了一般镜像法的一个准则。     

计算两不同平行轴间距柱形电容器电容的保角变换法

介绍了保角变换法,利用保角变换中常用的对数变换和分式变换,分别计算了不同平行轴间距的柱形电容器的电容,并进行了讨论。结果表明,当两轴间距离平方等于内外圆柱半径平方之和的2倍时,电容器的电容与同轴电容器是等效的;当两轴间距分别为大于内外半径之和,或小于内外半径之差时,两种情况下,两轴间距的平方之和等于内外圆柱半径平方之和的2倍时,两种电容器的电容等效。     

光波导的有限差分光束传播法设计及分析

讨论光波导数值计算方法中的有限差分光束传播法(FD-BPM)的设计与分析.从光波导理论、光波导数值算法、偏微分方程的差分方法引入FD-BPM算法.讨论了边界条件的计算及作用.结合具体光波导结构,运用FD-BPM算法进行数值计算;对得出的结论,通过改变不同参量,进行了结果的比较和分析.     

波动方程差分解法对波导螺钉调配器的分析

对波动方程差分解法(WEFD: Wave Equation Finite Difference Method)进行了研究,提出了一种新的不共点网格形式的WEFD算法,避免了原算法在导体表面需要插值处理的缺点.将此方法应用于矩形波导螺钉调配器中,所述方法的计算结果和有限元法软件(HFSS)计算结果较为一致,说明了该方法的有效性.     

用保角变换法计算任意源激励的任意截面柱体的辐射场

利用保角变换方法，将奇异性边界变换为简单光滑的边界，从而使点匹配法计算表面电流时能自动控制边界的划分和匹配点的选取，因而它能处理任意截面导电柱体的散射问题。本文进一步将保角变换方法与互易定理结合起来，这一方法可以处理任意截面柱体旁天线辐射的一般问题。本文计算了无限长正四棱柱对平面波的散射并与圆柱的散射进行了比较；并计算了无限长导电正四棱柱分周向半波振子的辐射并用矩量法的结果进行了验证。     

Improved Locally Conformal Finite-Difference Time-Domain method for edge inclined slots in a finite wall thickness waveguide

An Improved Locally Conformal Finite-Difference Time-Domain (ILC-FDTD) method is presented in this paper, which is used to analyze the edge inclined slots penetrating adjacent broadwalls of a finite wall thickness waveguide. ILC-FDTD not only removes the instability of the original locally conformal FDTD algorithm, but also improves the computational accuracy by locally modifying magnetic field update equations and the virtual iterative electric fields according to the complexity of the slot fringe fields. The mutual coupling between two edge inclined slots can also be analyzed by ILC-FDTD effectively.     

A novel research of confidential communication based on the elliptic curve and the combined chaotic mapping

This letter presents a new type of chaotic encryption system based on combined chaotic mapping pseudo-random number generator, Hash table, and elliptic curve. In this program, the elliptic curve algorithm is used for the key distribution. After the linear transformation, the original chaotic sequence generated by drive system will be combined to chaotic mapping, converted to an encryption key sequence and constructed as Hash table for message authentication. The communication experi-ment used in the letter proves that the combination of combined chaotic encryption and conventional encryption is safe, feasible, and easy to implement by software.     

差异特征与融合算法的集值映射关系的建立

针对红外偏振和光强图像现有融合算法无法随着图像差异特征的变化而优化选择的问题,提出了图像差异特征和融合算法的集值映射关系的建立方法.通过图像差异特征的分析与提取构建了差异特征集,将典型融合算法构建为融合算法集,利用数据包络分析法计算每个差异特征对各融合算法的融合有效度并构造融合有效度分布,通过对多组图像的融合有效度分布合成,建立差异特征与融合算法的集值映射关系.实验证明,所建立的集值映射关系可以优化选择融合算法,将互补性强的差异特征有效融合.     

基于并行FDTD方法分析表面等离子波导的特性

设计了一种双L形表面等离子体矩形环谐振器波导,采用并行时域有限差分方法,对这种波导的传输特性随几何结构参数的依赖关系进行了分析.计算结果表明通过改变输入/输出光波导的结构参数,可以调节该波导的消光比和频率选择特性.该波导结构能够有效地抑制后向辐射干扰并且大幅度地提高其场消光比,这使得此类谐振器结构更具有功能性.     

Quantum states of a hydrogenic donor impurity in a cubic quantum dot by the finite difference method

The problem of a hydrogenic donor impurity in a cubic quantum dot with finite confinement potential is solved by the finite difference method. The discretized matrix equation needs to be solved for its eigenvalues and eigenfunctions. An algorithm of nonlinear programming is utilized for this problem. The results match references qualitatively in the weak regime, but introduce new problems in the strong and intermediate regimes.     

细线结构时域电场积分方程的有限差分求解

提出一种求解基于细线结构的时域电场积分方程 ( TDEFIE)的方法 -有限差分方法。与传统求解时域电场积分方程的时域矩量法相比 ,该方法易于数值实现。文中还利用该方法研究了电磁辐射、散射的三个经典问题 ,并将结果与时域矩量法的结果进行了比对 ,研究表明 ,该方法求解细线结构的 TDEFIE非常有效。     

An improved radial basis function based method for image warping

A new image warping method is proposed in this letter, which can warp a given image by some manual defined features. Based on the radial basis interpolation function algorithm, the proposed method can transform the original optimized problem into nonsingular linear problem by adding one-order term and affine differentiable condition. This linear system can get the steady unique solution by choosing suitable kernel function. Furthermore, the proposed method demonstrates how to set up the radial basis function in the target image so as to achieve supports to adopt the backward re-sampling technology accordingly which could gain the very slippery warping image. The experimental result shows that the proposed method can implement smooth and gradual image warping with multi-anchor points‘ accurate interpolation.     

Transmission properties of the single mode fiber with a cross-sectional micro-channel investigated using time-domain finite difference (FDTD) method

Light scattering by a micro-channel intersecting core of a single mode fiber (SMF) has been investigated by use of two dimensional time-domain finite difference (2D-FDTD) method and the numerical results are in good agreement with those reported in the experiments. The transmission properties of the SMF with such a micro-channel can be attributed to the combined results of scattering effect and FP resonance effect. It is suggested that the SMF with micro-channel of about 4–6 μm in diameter can be effectively used for refractive index sensing with a high refractive index resolution up to ∼10⁻⁵.     

非线性薄膜波导的有限差分法计算

对于芯区为非线性介质、覆盖层和衬底为线性介质的平板波导,以克尔型薄膜为例,用有 限差分法导出了非线性波导的场分布和功率的数学表达式,并给出了典型实例的计算数据和 曲线。这种方法编程十分简单,有普适性,可精确求得非线性薄膜波导中场强与功率的分布。