爬行波电流传播常数及幅度的计算

本文提出了一种计算金属圆柱表面爬行波电流传播常数和幅度的新方法。该方法在获得金属柱表面爬行波电流的精确数值解后，应用Ｐｒｏｎｙ方法得了金属表面爬行波电流各个模的传播常数和幅度，避开了传统方法解时冗长、繁锁的数学推导过程。经比较，本文方法的计算结果比几何绕射理论的计算结果更为精确。     

弯波导的本征模与角传播常数

本文采用严格的本征模表示矩表截面均匀弯曲波导中的场，文中给出了虚阶Ｂｅｓｓｅｌ函数及其导数的计算公式和计算方法，由此完整地解决了任意半径弯波导本征征模及角传播常数的精确计算问题，典型数值计算结果表明，弯波导中的本征模与直波导中的本征模具有一一对应关系，变波导的等效传播常数与直波导的传播常数在数值上相当接近，模场的径向分布则呈衰减的驻波形式。     

Propagation Constants of Circular Cylindrical Waveguides Containing Ferrites

The paper describes some results of a theoretical and experimental investigation of the propagation behavior of circular cylindrical wave guides containing longitudinally magnetized ferrite rods. As long as no concentration of the RF-magnetic field in the ferrite occurs, theoretical expressions for the propagation constants can be given by applying first-order perturbation method. Faraday rotation measurements have been made between 5000 and 7600-mcs using commercially available ferrites. Reasonable agreement between theoretical and experimental results has been found for a thin axial ferrite rod in an air-filled guide in both cases of saturated and nonsaturated ferrites. Energy concentration in the ferrite determines the propagation behavior in the partially filled waveguide. This effect can be enhanced by surrounding the ferrite rod with a dielectric tube. For a given rod diameter and permittivity of the tube there is an optimum outer diameter of the tube for which the Faraday rotation becomes maximum.     

Experimental Study on Leaky Cable for Propagation Constants

The results for our experimental study on propagation constants for leaky cables are reported. The experimental results are compared quantitatively with the theoretical data, which are encouraging.     

波导参数和传播常数对光折变表面波的影响

基于质点振荡的模型和数值模拟的方法,研究了波导参数和传播常数对光折变晶体与线性电介质界面光折变表面波类型和局域表面波模的影响。当波导参数大于传播常数时,在光折变晶体与线性电介质界面可以产生非局域表面波。当波导参数小于传播常数时,在光折变晶体与线性电介质界面可以产生振荡表面波和局域表面波。在局域表面波形成的系统内,正波导参数的光波能量比负波导参数的光波能量在光折变晶体内聚集得多。在给定一个局域表面波形成的物理系统,传播常数越大,表面波在线性电介质和光折变晶体中衰减就越快,对应表面波模的波峰离界面就越近。     

Calculation of Propagation Constants and Cutoff Frequencies of Radially Inhomogeneous Optical Fibers

Based on the finite-difference technique, an efficient numerical method that can treat both the propagation constants and cutoff frequencies of optical fibers with arbitrary permittivity profiles is developed in the rigorous vector form. Such a propagation problem is formulated in transverse fields so that the proposed method does not suffer from spurious modes. The associated boundary conditions including those at cntoff are derived in a novel way. Thereafter, numerical results of the cutoff frequency and propagation constant of a fiber with the parabolic profile are presented.     

Propagation Constants of a Waveguide Containing Parallel Sheets of Finite Conductivity

The propagation constants of a rectangular waveguide containing periodic, parallel sheets having finite conductivity were determined using an iterative computer program. The dispersion equation was found in a matrix formulation which was conducive to computer solution. This equation was solved for various values of conductivity and sheet spacing. Comparisons were made with the propagation constants found assuming an infinite array of thin parallel resistive sheets in free space for the case where the direction of propagation and the electric field vector were both parallel to the sheets. The propagation constants for the infinite array case have been determined by both conformal mapping techniques for certain limiting conditions and by a computer solution of the dispersion equation for sheet spacings and conductivities of interest. The results should prove useful for the design of absorbing elements and terminations for waveguides.     

Complex Propagation Constants of Bent Hollow Waveguides with Arbitrary Cross Section

An integral representation of the complex propagation constant has been derived from Maxwell's equations for cylindrical, hollow, bent, oversized waveguides with uniform curvature and with arbitrary cross sections. The method makes the calculations much simpler than the conventional method, i.e., the characteristic-equation method, although it has not yet been tried for three-dimensional bent waveguides.     

用632．8nm激光精密测量费尔德常数

利用６３２．８ｎｍＨｅ—Ｎｅ激光和法拉第调制方法对甲醇、乙醇、乙二醇和氯仿、溴仿的费尔德常数进行了精密测量。详细描述了测量技术。     

Propagation Constants for TE and TM Surface Waves on an Anisotropic Dielectric Cylinder

Maxwell's equations for wave propagation in a cylindrical anisotropic dielectric rod have been solved for various values of the longitudinal and transverse dielectric constants with the help of an IBM 7090 computer. The solutions are limited to modes having no rotational dependence about the direction of propagation. Families of curves for various ratios of longitudinal to transverse dielectric constants are given, showing the relationship between the guided wavelength and the diameter of the rod. Equations for the cutoff and asymptotic behavior are also given.     

The Propagation Constants of Higher-Order Modes in Coaxial Waveguides With Finite Conductivity

Overmoded coaxial waveguides have been used in coaxial gyrotrons as a key interaction structure. To achieve the required mode selectivity, the resistivity of the center conductor is properly chosen to damp unwanted modes. Considering attenuation due to conductor loss, this study employs the perturbational method to determine the propagation constants of higher-order modes in the coaxial waveguide. The validity of the theoretical model is confirmed by comparison with results obtained using the high-frequency structure simulator (HFSS). Moreover, the method proposed herein is applied to analyze the ohmic mode selection of the coaxial waveguide.     

天线模型测量液体复介电常数

伴随着材料研究技术的进步,曾经很少使用的液体材料也逐渐得到重视。该文考虑到同轴探针在液体中辐射的存在,建立了被测液体介电常数与端面反射系数之间的等效电路模型（天线模型）,在理论上摊导了它们之间的函数关系。该丈对处于不同温度下的多种液体材料进行了测量,并对测试结果进行了分析。高介电常数材料去离子水在不同温度下的测试结果与cole-cole公式的计算结果对比表明：可测试频率达20GHz,复介电常数实部测试偏差和虚部测试偏差均不超过5％。中低介电常数材料丁业乙醇的测试结果表明：复介电常数的实部和虚部测试偏差均低于3％,测量精度高。     

Measurement of Optical Constants of CVD-Diamond for Short-Wavelength Far-Infrared Lasers

A diagnostic system using short-wavelength far-infrared (FIR) lasers (40–70 μm in wavelength) is now being developed for high density and large volume plasmas. In the wavelength region, a CVD-diamond is the excellent materials for optical windows of the laser and the plasma vessel and beam splitters of a multichannel interferometer. To design these optical elements, the optical constants (refractive index n, absorption coefficient α and transmissivity T) of the CVD-diamond have been measured precisely by using FIR lasers of 48-, 57- and 71-μm in wavelength. As an example, the result for 57.1511 μm light is n = 2.383(1) ± 0.002, α = 0.19 ± 0.05 cm^-1 and T = 97.5 ± 1.5% at 1.023 mm in thickness.     

Propagation Constants in Rectangular Waveguide Partially Filled with Dielectric (Correspondence)

There is considerable current interest in the production of guided electromagnetic waves having phase velocities equal to or less than the speed of light in free space (for example, in the design of traveling-wave slot antennas and of devices involving electron traveling-wave interactions). Such phase velocities can be obtained conveniently by partially loading a rectangular waveguide with dielectric material. In antenna work particularly, because of the field configurations, it is usually desirable to place the dielectric interface so that it is parallel to the broad face of the waveguide, as indicated in Fig. 1. The calculation of phase velocities in such a waveguide has been considered in the literature, and there is published information on some of the cutoff frequencies, but (since in this case there is no convenient relationship between the cutoff frequencies and the propagation constants) there has been little detailed information available concerning the phase velocities as a function of waveguide proportions and dielectric material. Thus a compilation has been made of such information for the dominant (hybrid) mode.     

Vector Analyses of Propagation Constants in Dielectric Optical Waveguides with Perturbed Refractive-Index Profile

A new method is developed to evaluate the propagation constants of guided or leaky modes in cylindrical dielectric optical waveguides with arbitrary cross sections. It is assumed that the refractive-index profiles of the fiber deviate from the step-index ones. Format expressions of the propagation constants are given for waveguides with anisotropically perturbed refractive-index profiles. The method is applied to a circular step-index fiber with an azimuthally perturbed refractive-index profile, and it is shown that scalar analyses cannot properly predict the propagation constants of those modes whose angular order satisfies certain conditions with respect to the Fourier spectrum of the perturbation of the refractive-index profile.     

涂层圆柱爬行波传播常数和模式阻抗的分析与计算

本文分析了介质涂层圆柱爬行波的电磁特性。找到了一种求解爬行波传播常数和模式阻抗的有效方法－微扰－迭代法，这种方法简单、快速，便于工程应用。最后给出公式并计算了一些实例。     

Theory of a Strip-Line Cavity for Measurement of Dielectric Constants and Gyromagnetic-Resonance Line-Widths

The cavity consists of a half-wavelength or wavelength of strip-line, short-circuited at both ends, and open along the sides. For measurements of dielectric and magnetic properties of samples, it has two apparent advantages over the more usual coaxial line method: the sample is simpler in shape, and it can be inserted without dismantling the cavity. Perturbation formulas are obtained for the frequency shift and change of "Q" on inserting a sample into a position of zero electric or zero magnetic field. The "Q" of the cavity in the absence of a sample is calculated by a perturbation method. The limiting sample size for a given accuracy to be obtained is also discussed.     

Hg1—xCdxTe光学常数测量

根据半导体光学常数间的关系,通过测量Hg_(1-x)Cd_xTe晶片不同厚度时的透射比,求得了Hg_(1-x)Cd_xTe的光学常数。本文采用迭代法精确求解有关方程组,避免了计算过程引入的误差,提高了测量结果的精度。这种方法也适用于其他半导体光学常数的测量。     

微带线法测量微波材料的复介电常数

电磁波传输介质的电磁参数的准确测量,对材料的实际应用十分重要。研究微波材料介电常数的微带线测量方法,通过正演和反演过程的求解分析,对不同介电常数的材料进行了实际计算,同时还对测试误差进行了简要分析。结果表明,微带线测试微波材料的复介电常数方法可行,测量过程较为简单,测量结果准确。     

Computation of Propagation Constants for the Fundamental and Higher Order Modes in Microstrip (Short Papers)

A method used to treat static problems in microstrip is extended to treat time-harmonic problems of covered and uncovered microstrip. Both longitudinal and transverse currents are taken into account, Impedance functions (integrals of Green's functions) for covered and uncovered microstrip are derived in terms of improper integrals (limits 0 --->/spl infin/). Accurate evaluation of these integrals is carried out. Matrix methods are then used to obtain propagation constants for the fundamental and higher order modes. Data obtained agree closely with experiment.