The Dominant Cutoff Wavelength of a Lunar Line

A method is presented for calculating the lowest cutoff wavelength of a new microwave transmission line, the "lunar line," which is formed by two eccentric circular metal tubes connected with a metal bar or tangential to each other. The lunar-shaped cross section is approximated by introducing a series of steps in the outer guide wall and by dividing the cross section into m fan-shape regions. Thus, the problem is reduced to one of a multiple-step waveguide and can be solved by introducing the angular parameter alpha/sub i/ for the individual regions. The radial boundary conditions require a combination of Bessel functions of noninteger order for each region. The common boundaries between regions give m integral equations that represent the total power in one region transferred into the next region. The integral equations are solved approximately by solving only the first terms of an infinite series expansion of the tangential electric field at the common boundary. The solution of the m-stepped waveguide results in a system of 2m equations containing 2m unknowns: the cutoff wave number beta/sub c/, the order of the Bessel function p/sub i/, and the angular parameter alpha/sub i/. A successive approximation method is applied to obtain the cutoff wavelength. The calculated value is in close agreement with experimental results.     

Finite Element Method Analysis of the Cutoff Wavelength of Dominant Mode in Unilateral Finline

The cutoff wavelength of dominant mode in unilateral finline is analyzed by finite element method. The cutoff wavelength can be changed by adjusting the thickness of metallic fins and dielectric constant of dielectric substrate. Numerical results provide in this paper have important values in practical applications.     

微屏蔽传输线的分析与计算

微屏蔽线（ＭＳＬ）是一种新型的平面传输线，其超高的频率响应和极低的色散特性，可望广泛地应用于各种毫米波电路中，本文把用于鳍线、微带线的谱域导抗法推广到这种半封闭的传输线中，分析、计算了两种微屏蔽传输线的色散特性。计算结果与有关的实验相吻合，为这种半封闭的新型毫米波传输线提供了一种有效的计算方法。     

五角波导TM模截止波数的边界元分析

推导了常数单元边界元法求解波导本征值问题的矩阵计算公式，应用常数单元和线性单元边界元法计算五角波导TM模的截止波数，两种方法计算所得结果与文献中已有结果吻合良好。     

一种方同轴波导中高次模截止波长的求解

提出了一种方同轴波导高次模截止波长的求法，文中使用有限差分法，并对不同的边界条件进行了处理。对于离散形式的数值方程，采用双重高斯塞德尔迭代法求解，并进行了改进．从而极大地提高数值解收敛的速度。最后分析了结果的合理性。     

不对称脊波导截止波长的计算

将计算矩形波导和对称脊波导导内波长的横向谐振法推广用于计算不对称单脊波导的导内波长和电中心线对波导宽边几何中心线的偏置。介绍了为保证脊波导截止波长或导内波长不变的情况下,设计不对称脊波导的方法,并给出了一些计算结果和试验结果。     

基于微屏蔽线的140GHz低通滤波器研究

微屏蔽传输线是一种采用薄膜支撑的传输线结构,具有损耗小、阻抗可变范周大的特点。利用保角变换的方法对微屏蔽线单位长度的电容进行了分析,给出了单位电容值与相对介电常数、特征阻抗的关系。利用阶跃阻抗的结构．设计一个5阶的带内波纹为0．5dB、截止频率为140CHz的切比雪夫低通滤波器,并用HFSS仿真分析其传输特性,在滤波器的末端串联短接式短截线结构增强其带外抑制作用。     

矩形变形脊波导主模截止波长的计算

为了满足微波传输系统性能的某些需求,各种结构形状的新型波导应运而生.采用有限差分法,利用Matlab计算了变形矩形脊波导在改变波导内部脊的位置、形状和大小等不同情况下的波导主模截止波长,并对计算结果进行了对比分析,得出了主模截止波长随着内脊的高度、宽度、上下脊高度及宽度比例的变化而变化的一些相关结论.     

Matlab求解方同轴波导的截止波长和特性阻抗

采用有限差分法利用Matlab求解了方同轴波导的特性阻抗和高次模的截止波长，并将数据与国外文献数据进行了对比，证明了有限差分法结合Matlab在分析简．单截面的同轴波导时是简单可行的，而且计算精度较高，通用性强，可以用于传输线工程问题的设计和计算。最后计算了矩形同轴线的相关数据用于与方形同轴线作对比。     

基于直线拟合的细胞边缘形状描述方法

在分析细胞边缘形状特征基础上，用改进的Hough变换实现了细胞边缘的直线拟合。通过分析直线长度序列、直线间角度序列特征，对细胞形状进行了初步分析与描述，并成功地提取了多边形细胞与其他细胞间的特征区别。     

On the Dominant Mode in Closed Trapezoidal-Groove Guide by Finite Element Method

The structure of closed trapezoidal-groove guide is similiar to that of open one, but it can be used to prevent energy from leaking out of the guide. In this paper, the propagation characteristics of dominant mode in closed trapezoidal-groove guide are analysed by using finite element method and the results are discussed.     

On Single-Mode Bandwidth in Rectangular-Groove Guide by Finite Element Method

The single-mode bandwidth in rectangular-groove guides with different dimensions has been studied by finite element method. The actual single-mode bandwidth in a rectangular-groove guide is the same with a rectangular guide with the similiar dimensions. The dominant single-mode transmission in a rectangular-groove guide at millimetric waveband by adjusting the guide dimensions can only be an approximate one.     

脊的变化对对称双脊波导主模截止波长的影响

关于双脊波导的研究报道很多,但对双脊波导的研究都集中于脊中心对称情况,对于脊偏离中心位置的情况则没有涉及.采用对亥姆霍兹方程有限元方法分析了脊的变化对双脊波导主模截止波长的影响,数值结果与文献结果对比,计算方法精确有效,从而可以通过改变脊尺寸和位置调节截止波长.     

熔体外延法生长截止波长8～12μm InAs1-xSbx单晶的透射光谱

用熔体外延法在InAs衬底上成功地生长了截止波长为8～12mm的InAs1-xSbx单晶.用红外光谱仪测量了样品的透射光谱.提出了组分微观分布函数的概念,并计算了InSb单晶和3种不同组分InAs1-xSbx样品的透射光谱.结果表明,实验测得的样品截止波长与计算得到的数据基本一致,从而证实了熔体外延法生长的InAs1-xSbx单晶的禁带宽度变窄现象,并认为组分微观分布的不均匀性可能影响Ⅲ-Ⅴ族混晶的能带结构.     

UTP的有限元建模

本文应用有限元方法对非屏蔽双绞线（UTP）进行建模，为了验证仿真结果的可信性，结合磁偶极子理论和场强叠加原理，对双绞线的辐射场进行理论计算．结果证实，有限元法在处理双绞传输线问题上是有效可行的。     

基于小波边缘检测的红外波长测温法研究

利用小波边缘检测的方法,通过对红外辐射能量与温度、波长关系的分析,推导出两个 具有普适意义的拐点波长位移公式,提出并论证了红外波长测温理论。理论证明,利用红外波长测温法测得的三个温度值具有互校性,可用来校验绝对黑体,并为红外测温提供了一种全新的方法。     

不对称脊波导脊位置对主模截止波长的影响

用有限差分方法分析不对称脊波导中脊位置变化时对主模截止波长的影响。截止波长可以通过脊位量的调整而调整。并给出了一些计算数据。     

On the Main Mode of Trapezoidal-Groove Guide By Finite Element Method

In this paper, the propagation properties such as the dispersion characteristics, cut-off wavelength, guide wavelength and field distribution for the main mode of trapezoidal-groove guide are analysed by using the finite element method. The dispersion is very low, and the field distribution in a trapezoidal-groove guide is similar to that of rectangular one. The results have important values in design, manufacture, and application of groove guides.     

The Cutoff Wavelength of the TE/sub 10/ Mode in Ridged Rectangular Waveguide of Any Aspect Ratio

Design curves for ridged rectangular waveguides of the usual aspect ratio of 0.45 were published by Hopfer following earlier work carried out by Cohn and Marcuvitz. This paper has been written to extend the design data to ridged rectangular waveguides of any aspect ratio. An analysis of the error introduced by proximity effects has shown these to be of the order of a few percent.     

TLM方法在计算方波导的截止频率中的应用

传输线矩阵(TLM)是一种强有力的时域和空域电磁场数值仿真算法,它的出现在各个领域引起了广泛关注.文中在简单介绍TLM原理后,对方波导的截止频率用Matlab语言进行编程计算,计算结果与理论计算值吻合.基于Huygens波传播模型的传输线矩阵方法与计算机结合起来后,成为一种强有力的时域电磁场数值仿真算法.