曲边介质波导的有限元分析

本文应用曲边有限元方法有效地计算了曲边介质波导的色散特性,编制了相应的计算程序。应用本文方法计算得到的椭圆介质波导和组合椭圆介质波导的主模和高次模的色散曲线与文献[2]、[3]的结果相当吻合。     

任意曲线槽波导色散和损耗特性的高次有限元分析

本文用高次有限元法分析了任意形状槽波导的色散和损耗特性.该方法的有效性和可靠性由实验和其它计算结果所证实.文中对诸如矩形、三角形、抛物、椭圆和余弦等形状的槽波导进行了系统的研究.计算结果表明,不同形状槽波导具有相近的色散特性,但损耗相差很大,其中V形槽波导损耗最小,大约是矩形槽波导的一半.文中给出的曲线可供设计槽波导元件和电路时参考.     

任意曲线槽波导色散和损耗特性的高次有限元分析

本文用高次有限元法分析了任意形状槽波导的色散和损耗特性。该方法的有效性和可靠性由实验和其它计算结果所证实。文中对诸如如矩形，三角形，抛物，椭圆和余弦等形状的槽波导进行了系统的研究。计算结果表明，不同形状槽波导具有相近的色散特性，但损耗相差很大，其中Ｖ形槽波导损耗最小，大约是矩形槽波导的一半。文中给出的曲线可供设计槽波导元件和电路时参考。     

椭圆手征波导的导模特性研究

该文首先对椭圆手征波导进行了解析求解,导出了模式场解及模式特征方程,然后用数值计算的方法研究了手征参数对椭圆手征波导中导模的色散曲线和截止波长的影响,发现在椭圆手征波导中导模的第一个模式会随手征参数的增加而不同。     

分析曲边截面波导主模特性的新方法

本文提出了分析曲边截面波导主模特性的一个新方法。分析方法是基于网络级联技术和横向谐振法的结合。通过对几种曲边波导主模传播特性的数值例算,表明本文方法精度较高,且简单易行,特别适合于实际工程应用。     

圆波导结构中TM0和TE0模式传输特性的时域分析法

本文提出了一种适合于求解各类复杂圆波导结构ＴＥ０和ＴＭ０模式的截止频率和色散曲线的ＦＤＴＤ分析方法，并可在一维空间中加以处理，大大提高了计算效率和减少了存贮量。本文对圆波导中ＴＥ０和ＴＭ０模式的截止频率和色散曲线进行了计算和分析，同时分析了网络剖分对计算结果精度的影响，并与已知的理论结果进行了比较，证实了这一方法的可靠性。作为实例，计算和分析了表面波圆波导结构的色散曲线，所得结果与实验结果和其它数     

基于矢量有限元的任意介质加载波导通用软件设计

本文旨在实现波导问题的通用软件设计,文章完善了各向异性介质填充波导问题的矢量有限元理论,并计算了有耗、各向异性介质加载的任意结构波导模式传输系数、色散曲线和模式电场分布。在计算色散曲线时,本文结合了模式场图以消除HFSS在色散计算过程中对传输模式的误判。对于开放结构波导,采用各项异性介质的完全匹配层（PML）理论实现无限的问题截断。通过与商业电磁仿真软件的计算结果作比较,验证了算法的精确性。     

螺旋槽波导特性的计算与模拟研究

计算了螺旋槽波导的色散特性和群速度,用“准周期边界条件”方法和谐振法模拟计算了螺旋槽波导的色散特性,两种方法的模拟结果与计算都比较一致。此外,还模拟测试了渐变与规则螺旋槽波导连接的匹配性能、螺旋槽波导高频系统的传输特性。结果表明,螺旋槽波导是非常适用于回旋行波管的高频结构。     

用高斯近似计算单模α光纤的色散参数

本文提出了一套计算波导色散参数的新方法。用它检验了两种常用的高斯近似对色散参数计算的影响。並在此基础土,提出了光斑的一个新定义,给出了用它近似计算单模α光纤波导色散参数的简单解析公式及其计算结果,还对一些例子做了比较。     

槽波导色散特性的模匹配法分析

槽波导是一种很有前途的毫米波传输结构。本文用模匹配法分析了单槽波导和非对称双漕波导的色散特性,给出了n阶近似的色散方程的一般公式,据此编制了求解单槽波导和非对称双槽波导色散特性的通用程序,利用该程序对若干单槽和非对称双槽波导色散特性进行了计算,并与已有的数据进行了比较,获得了十分一致的结果,从而证实了所给公式和程序的正确性和可靠性。     

Finite-Element Analysis of Dielectric Waveguides with Curved Boundaries

The modes of dielectric waveguides with curved boundaries are computed efficiently using a curved-sided (isoparametric) second-order finite element rather than the more usual triangular element. A novel way of placing the virtual boundary is described. Results are obtained for dielectric rod and elliptical waveguides, and compared with earlier results. The method is used to analyze a single-mode fiber-optical coupler.     

An implementation of the vectorial finite element analysis ofanisotropic waveguides through a general-purpose PDE software

This paper reports on the major progress in the development of an intelligent, interactive and automated system, based on the vector finite element method, and implemented within PDE/Protran problem solving environment. The system is known as WAVEGIDE and was originally developed by the authors for an efficient solution of inhomogeneous dielectric waveguides. In this paper, it has been further extended to the solution of anisotropic waveguiding structures. With our system, through an interactive “question-and-answer” session, which requires minimal knowledge of programming, the problem can be defined using high level PDE/Protran commands. It can then be simply and quickly solved by the main processor within this intelligent environment. To verify the convergence and accuracy of the present approach, numerical results (with respect to the grid density and element order) for a rectangular metallic waveguide half filled with dielectric are given and compared with other finite element methods. Numerical results for an anisotropic dielectric rectangular waveguide are also presented. These results clearly illustrate the accuracy and the ease of use of the modified WAVEGIDE program     

A Variational Theory for Wave Propagation in Inhomogeneous Dielectric Slab Loaded Waveguides

A novel numerical technique based on the variational formulation defined only in the slab is developed to study the loaded rectangular waveguide with an inhomogeneous dielectric slab. The variational equation for the boundary value problem is formulated and solved numerically, using the finite element method with piecewise quadratic trial functions. A comparison of this new technique with the conventional variational ones is presented. Various propagation characteristics, such as the phase constant, useful bandwidth, power handling capacity, and attenuation constants due to conductor and dielectric losses, are investigated for the waveguide centrally loaded with a slab of parabolic dielectric profile. The effects of changes in dielectric profiles are discussed by examining the results for the slabs with constant and parabolic profiles.     

介质填充非对称倒梯形单脊波导传输特性研究

倒梯形单脊波导具有衰减常数小、特性阻抗低、功率容量大的特性,故其适用于微波传输.研究发现填充介质倒梯形脊波导有利于实现波导小型化.采用有限元法结合Matlab编程,研究了不同对称度下的填充非对称倒梯形单脊波导的截止波长、单模带宽、衰减常数、功率容量和特性阻抗.研究结果表明:对称度较小时,填充位置在短臂侧时所得的截止波长最长,单模带宽最宽,功率容量最大,阻抗特性最小.研究结果将为填充非对称倒梯形单脊波导的应用提供理论依据.     

填充介质倒梯形脊波导截止特性的有限元分析

为了寻找最佳截止特性的填充介质脊波导结构,提出了填充介质倒梯形对称双脊波导.采用有限元法借助MATLAB软件计算了填充介质倒梯形对称双脊波导在TE模式下的截止特性,即主模截止波长和单模带宽.绘制出主模场结构图,并分析脊波导截止特性与填充介质相对介电常数之间的关系,给出了关系曲线图.这些结果将对填充介质波导的设计和工程应...     

A comparison of formulations for the vector finite element analysisof waveguides

The principal formulations that have been proposed for finding the modes of waveguides by the finite element method are reviewed and compared. In each case, it is shown how Maxwell's equations may be reduced to matrix form using the method of weighted residuals. The formulations are compared from several points of view: their ability to handle spurious modes, lossy materials, and reentrant corners; the number of field components; and the properties of the matrices. Three benchmark problems are described and used to compare the formulations: a rectangular waveguide partially loaded with lossless dielectric; an air-filled, double-ridged waveguide; and a shielded image guide with either lossless or lossy dielectric     

Equivalent network analysis of dielectric thin-film waveguide with trapezoidal cross-section

Equivalent network approach has been applied to the guided wave problems in the dielectric thin-film waveguide with trapezoidal cross-section. The results by this simple approach for the trapezoidal rib waveguide agree well with the experimental results and the results of the finite element method.     

用于毫米波焦面成像阵的介质加载波导阵元分析

分析了有望用于毫米波成像焦面阵的介质加载波导阵元，采用时域有限差分法(FDTD)计算输入特性，优化了输入基本匹配时的结构尺寸参数，计算该结构参数下的阵元与成像透镜衍射场Airy斑的耦合效率并与其它阵元做了比较。     

极坐标系中的B样条有限元法解波导本征值问题

本文提出了用极坐标系中的Ｂ样条有限元法解波导本征值问题，该方法有两个突出优点：（１）避免某些含曲线边界的波导截面的剖分误差；（２）改善尖角波导的计算精度，本文首先建立了极坐标系中Ｂ样条有限元方程，然后通过对圆形，扇形，双脊加圆形和心形波导本征值问题的实际计算，表明方法的有效性和实有价值。     

波导介质不连续性问题的FEM/PML方法分析

将完全匹配层(PML)与矢量有限元方法(FEM)相结合对波导介质不连续性问题进行分析。利用PML对计算区域进行截断，大大节省了FEM分析问题的内存消耗。对波导的单介质块加载问题的S参数进行了分析计算，数值结果与文献结果一致。在此基础上，计算了多介质块加载波导的散射参数。数值结果证实了应用FEM／PML方法对波导介质不连续性问题进行分析的正确性与有效性。