Electromagnetic Wave Propagation in Lossy Ferrites

The square of the complex transverse propagation constant in a lossy, magnetized ferrite is found to be described approximately by a circle in the complex plane when the magnetic field is varied. A graphical method for obtaining approximate values for the transverse propagation constant when the wave number in the direction of the applied field is given and real is derived here. This method is used to find The power absorbed from an incident plane wave by A semi-infinite ferrite as a function of the magnetizing field amplitude.     

Iterative Solutions of the Scalar Helmholtz Equation in Lossy Regions

Iterative solutions to the finite difference equations derived from the scalar Helmholtz equation are found to diverge for domains greater than a certain size. A transform method is presented which produces convergence in larger domains. The method is illustrated by solutions for one- and two-dimensional cases involving lossy dielectric media.     

非均匀有耗传输线ABCD参量的求解

传输线理论是射频与微波电路的重要基础理论,而其中ABCD参量特别适用于分析级联网络的传输性能.本文针对非均匀有耗传输线的ABCD参量求解问题,建立传输线的数学模型,给出了三种解法,即级联法、微分方程法和积分方程法,并对三种方法的准确性和效率进行了讨论.     

高频电磁波在有损地面上的传播特性

对于架设在复杂环境的高频天线,用矩量法等算法计算环境对电磁波传播特性的影响非常困难,而了胡着高频技术的发展,这一现实问题迫切需要得到解决,本文利用时域有限差分法（FDTD）对这类问题进行了分析计算,文章计算了架设在海岸边的天线,其辐射的电磁波经过一段有损陆地后,远区电磁场的变化特性,由于存在不同介质的界面,在计算中引入了表面阻抗法概念,提高了运算程度。     

A Vector-Fitting Formulation for Parameter Extraction of Lossy Microwave Filters

In this letter, a formulation based on the vector fitting is applied to extract the equivalent circuit model from the frequency response of lossy cross-coupled microwave filters. By approximating the lossy response with short-circuit admittance parameters in partial fractional expansion form, the proposed method can evaluate the unloaded quality factor of resonators and extract the transversal coupling matrix simultaneously. The methodology of the vector fitting can identify the poles and residues of the short-circuit admittance parameters even when the poles are on the complex plane. And the extracted transversal coupling matrix can further transform into the prescribed form corresponding to the physical layout. The proposed method can be used in the tuning process of filter designs where the extraction of a coupling matrix is essential. To verify the method, a cross-coupled quadruplet filter is used as an example     

Linear Analysis of Traveling Wave Tubes with Nonuniform Lossy Interaction Structures

A linear theory model is developed to analyze traveling wave tubes (TWT) employing distributed wall loss. The loss can be a function of position. The electronic and circuit equation are derived, taking into account the spatial variation of the circuit loss. This model can be used to provide a first-cut design of the TWT.     

色散有损介质土壤对电磁回波影响的不确定性分析研究

不确定性分析是量化不确定性从而获得统计特性的过程.在数值模拟中,均值、标准差等统计特性是评价数值仿真结果是否合理的重要依据.针对探地雷达系统建模仿真输出结果的不确定性,本文提出一种改进的不确定性分析方法.该方法结合辅助微分方程时域有限差分法与广义多项式混沌展开方法,对色散有损土壤模型的不确定参数所引起的仿真输出结果的不...     

有损耗左手材料电波传播特性的FDTD分析

为研究电磁波在有损耗左手材料中的传播特性,采用时域有限差分（FDTD）法和色散媒质的Drude模型,推导出基于Drude模型的左手材料二维FDTD迭代方程。一维数值仿真结果验证了平面电磁波在穿过有耗左手材料时,其相速度大小与光速相同,方向与传播方向相反,且随着损耗因子的增大,左手材料内的电场强度幅值亦相应减小。此外,还利用多循环m-n-m脉冲作为激励源,对左手材料平板具有的完美透镜现象进行了二维数值仿真验证。结果表明,有耗平板左手材料具有明显的聚焦效果,在特定条件下能实现完美成像。     

Parameter Estimates of a Left Ventricular Model During Ejection

A network model of ventricular function consisting of a source of pressure with a series internal resistance that is coupled to a load resistance is presented. It is used as an analog of left ventricular (LV) function during the ejection phase of the cardiac cycle in order to quantitate the interaction of ventricle and load.     

Solution of the Fourier Heat Flow Equation in Waveguides Filled with Lossy Dielectrics (Correspondence)

The temperature distribution within a waveguide filled with a lossy dielectric, and propagating a specified mode, may be conveniently obtained by the Green's function method. Such a solution is useful for describing the temperature distribution in vacuum windows, for example.     

毫米波辐射探测目标亮温的估计

毫米波近感技术是利用物体的毫米波辐射特性探测识别目标，在许多领域有着重要应用。为在毫米波辐射探测中求得精确的真实目标亮温，必须建立天线电磁辐射与环境电磁辐射交会的数学模型，此模型是第一类病态Fredho1m积分方程。寻找适当的方法能得到一个尽可能好的或同精确值相当接近的近似计算方法，为此，本文给出毫米波辐射计目标辐射亮温的估计方法。     

On Design and Performance of Lossy Match GaAs MESFET Amplifiers

The noise figure, the gain, and the reflection coefficients of lossy match amplifiers and their dependence on circuit elements are studied. Theoretical results are supported by measured data taken on a two-stage unit. In addition, the performance characteristics of a 100-8800 MHz four-stage lossy match amplifier are discussed. The unit exhibits 23.3 +- 1.1 dB of gain over the nearly 6-1/2 octaves. Its maximum noise figure is 10.9 dB from 100-8800 MHz and 6.6 dB from 2000-8000 MHz. The amplifier's overall circuit dimensions are 10 X 5.7 mm..     

电磁格点理论在有耗介质涂层导体薄片上TE波散射中的应用

在ＴＥ波入射下，对于计算二维封闭导体柱散射问题所常用的磁场积分方程法，当用于导体薄片时将会失效．本文采用电磁格点理论和电场方法研究这个问题．结合二维介质柱的电磁格点方程，解决了有耗介质涂层导体薄片的ＴＥ波散射．文中给出计算实例．     

有耗介质柱体瞬态散射积分方程的新解法

本文研究二维非均匀有耗介质柱在电极化二维脉冲波激励下的瞬态散射。采用分片双线性插值的空间离散方案,经解析处理,子域上的积分能得到闭式结果。离散化方程在复频域用CG-FFT法求解,并用一种新外推法产生初值,数值结果证实了本文方法的有效性。     

On the Synthesis of Waveguides and Cavities Realized with Nonseparable Solutions of Helmholtz Wave Equation (Short Papers)

This short paper shows how nonseparable solutions of the Helmholtz wave equation can be used in the synthesis of waveguides and cavities with nonconventional cross section, and also investigates the attenuation and Q factor.     

电磁格点理论在有耗介质涂层导体柱TE和TM波散射中的应用

本文采用格点理论，建立了求解有耗介质涂层导体柱电磁散射（包括ＴＭ和ＴＥ两种情况）的基本方法。涂有有耗介质层的导体柱可以看成是一群由面格点和线格点组成的混合格点，分析它们的自作用和互作用，可以方便地解决散射问题。文中还给出了若干计算实例。     

运用多重网格方法求解波动方程

在众多的数值计算方法中，有限差分方法大概算是最早提出的方法之一其简便，灵活，易于实现的特点使该方法在大型科学计算中仍然占有一席之地。完全多重网格方法能够有效地解决有限差分方法中存在的收敛速度慢的缺陷。本文运用完全多重网格方法结合有限差分法和共形映射法求解Ｈｅｌｍｈｏｔｚ波动方程，计算了几个实际电磁问题并取得了良好的结果。具体算例说明这种方法是一种在现代数值计算领域中十分实用、简单、高效的新方法，在     

Inference on Weibull Percentiles and Shape Parameter from Maximum Likelihood Estimates

Four functions of the maximum likelihood estimates of the Weibull shape parameter and any Weibull percentile are found. The sampling distributions are independent of the population parameters and depend only upon sample size and the degree of (Type II) censoring. These distributions, once determined by Monte Carlo methods, permit the testing of the following hypotheses: 1) that the Weibull shape parameter is equal to a specified value; 2) that a Weibull percentile is equal to a specified value; 3) that the shape parameters of two Weibull populations are equal; and 4) that a specified percentile of two Weibull populations are equal given that the shape parameters are. The OC curves of the various tests are shown to be readily computed. A by-product of the determination of the distribution of the four functions are the factors required for median unbiased estimation of 1) the Weibull shape parameter, 2) a Weibull percentile, 3) the ratio of shape parameters of two Weibull distributions, and 4) the ratio of a specified percentile of two Weibull distributions.     

数字调频连续波测距雷达方程

数字调频连续波（DFMCW）测距雷达有多项工程设计参数,包括由于连续波收发隔离度限制发射高功率Ptmax、采用数字方式产生DFMCW信号的扫频带宽B、扫频时宽T（扫频信号重复周期）及DFMCW测距雷达接收机的中频量程带宽Bn、接收机动态压缩特性和采用数字FFT信号处理器的采样频率fs等。将对这些设计参数的定义进行说明,并与一般脉冲雷达或线性调频（LFM）脉冲压缩雷达的设计参数进行比较和等效估算,最后推导出DFMCW测距雷达工程使用的方程式。