EBG对圆波导介质棒相控阵扫描特性的改善

将电磁带隙(EBG)结构应用到圆波导介质棒相控阵列中,利用EBG结构所具有的表面波带隙特性有效消除了相控阵中的扫描盲区.比较了无限阵列的扫描特性和有限阵列中心单元方向图在EBG加载前后的变化.仿真分析表明,以EBG结构作为圆波导介质棒相控阵的地平面,能有效消除扫描盲区,扩展扫描范围.     

回旋媒质偏心加载圆波导的传输特性

利用基于Bessel函数加法定理的坐标变换,获得了关于回旋媒质偏心加载圆波导中传播常数的特征方程.文中给出了回旋介质棒偏心加载圆波导时的色散特性曲线,并讨论了传播常数随各参数的变化.     

方波导介质加载的特性分析

本文分析了介质加载方波导中模式的传播和截止特性,给出了有关的计算曲线,讨论了方波导移相器的带宽特性及工程设计中应该注意的一些问题。     

多手征介质填充圆波导的分析

本文利用递推本征函数法分析了多层手征介质填流圆波导的传播特性。文中给出了不同介质层中电磁场的递推关系，推导了Ｎ层手征介质填充圆波导色散特性的一般笥计算公式。作为示例，文中还给出了对几结构传播特性的计算结果。     

圆波导介质加载锁式铁氧体变极化器的实验研究

在实验基础上,本文给出圆波导锁式铁氧体变极化器的介质加载的研究结果．实验表明,在铁氧体环内适当加载介质,可明显提高器件的相移,而对插入损耗特性影响甚微．这一发现对改进器件性能,具有极大的实用价值     

单轴介质加载槽波导的色散特性

本文讨论了各向同性介质填充或部分填充槽波导的分区谱域导抗法,利用文献[7],直接半分区谱域导抗法应用到单轴各向导性介质。对单轴介质加载槽波导的色散特性进行分析,给出了数值结果。     

非线介质光波导传播特性研究

本文对非线性平板光波导ＴＭ模传播特性进行了研究；采用图解法解了光波导的色散方程；最后讨论了引起光波导传播特性变化的物理机制。     

月形波导和加片圆波导的解析分析

采用模匹配方法分析了月形波导和加片圆波导的截止频率。波导中的场采用半数阶Bessel函数展开并令其满足边界条件,从而获得截止频率的特征方程国。根据本文所给公式可求解任意尺寸的月形波导、倒月形波导和加片圆波导的截止频率,并获得稳定的、具有高精度的解。     

周期损耗介质加载波导与均匀圆波导间的模式映射

损耗介质环与金属环间隔加载的周期损耗介质波导能够有效地控制各种模式的衰减特性,这对于抑制毫米波回旋行波管放大器的绝对不稳定性和提高其性能具有重要作用.针对应用于Ka波段、TE01模的回旋行波管放大器的周期损耗介质加载圆波导,系统地分析了该周期系统与均匀系统间的模式映射关系.研究表明,当介质层厚度一定时,均匀介质加载波导中的高阶模式可以映射为光滑波导中的低阶模式,且相互映射的模式在中空区域的场型一致.周期系统中的模式表现出复合模式的分布.在一个周期中,介质段和金属段的模式分别映射为均匀介质波导和金属波导中的模式.明确周期介质加载波导系统与均匀波导系统间的模式映射关系是分析发生在这种复杂的互作用回路中的回旋电子脉塞注波互作用的前提,对简化其物理模型具有指导作用.     

介质加载圆形槽波导的分析

采用矢量基函数的有限元方法,在开放边界处采用完全匹配层(PML)截断无限区域。分析了在圆形槽波导不同位置加载平板状介质时的模式特点。分析表明介质加载时圆形槽波导的模式次序要发生变化,为设计圆形槽波导微波化学反应器提供了依据。     

Analysis of Dispersion Characteristics for a Circular Dielectric Rod Waveguide with Periodic Corrugations

The dispersion characteristics of a circular dielectric rod waveguide with period corrugations are analyzed with the mode matching method. After obtaining the rigorous dispersion equation, the dispersion curve for TE₀₁ mode exciting is calculated by the improved Newton's method. The variations of the normalized center frequency and width as well as the maximum attenuation constant of the stopband with the geometry parameters of the periodic corrugation structure are given respectively. The convergence properties of numerical solutions are also discussed. Based on the analysis, some useful guidelines for the design of the band-rejection filters consisting of the periodic structure are thereby suggested.     

Continuous Mode Spectrum of a Circular Dielectric Rod

The continuous modes for a circular dielectric rod are derived. These modes are identified with the fields due to the scattering of a plane wave at oblique incidence from a dielectric rod, thus providing insight into their behavior. This identification suggests that the modes be classified as incident transverse magnetic (ITM) modes when the incident plane-wave portion of H/sub z/ is zero and as incident transverse electric (ITE) modes when the incident plane-wave portion of E/sub z/ is zero. The transition region from discrete to continuous modes is analyzed in detail. Very simple approximate modes are derived for use in optical waveguide studies.     

偏心介质柱加载柱形腔的严格分析

本文给出偏心介质柱加载柱形腔模式的解析分析方法。该方法对任何模式均是严格的，且适用于各种相对尺寸及电参数。利用该方法精确求解了各高次模式谐振频率，并建立了模式图，讨论了谐振频率随腔体相对尺寸及加载介质电参数变化的趋势。     

Analysis of Circular Dielectric Waveguide with Chiral Cladding

The propagation characteristics of a circular dielectric waveguide with chiral media filled in the cladding are investigated. The relation between the cutoff frequency and the chiral admittance, the dispersion curves for some modes with different angular mode numbers and the transverse distribution of fields are presented. Some new features different from the ordinary circular dielectric waveguide are resulted. The results show that the cladding chirality may lead to a single-mode operation in the circular dielectric waveguide.     

Mode Matching Analysis for a New Millimeter Wave Omni-Directional Antenna Consisting of Circular Rod Corrugations Gloved with a Dielectric Shell

A new millimeter-wave omnidirectional antenna consisting of circular rod corrugations gloved with a dielectric shell is investigated. As an eigenvalue problem, the antenna is analyzed with the rigorous mode matching method. The radiation characteristics of the antenna are calculated in the Ka-band frequency range. A comparison of the leaky characteristics is made between the antennas with and without dielectric shell. It is found that the circular dielectric shell layer greatly affects the leaky characteristics of the antenna and the leakage constant increases considerably. In such a way, the length of the antenna can be reduced tremendously with higher radiation efficiency. This fact indicates that the proposed leaky wave antenna is of essentially practical significance for the case where the limitation in size and weight of system is strictly required. The effectiveness and reliability of the present analysis are verified by the calculated and experimental results given in the literature.     

Analysis of a Post Discontinuity in an Oversized Circular Waveguide

This paper presents the analysis of scattering characteristics of a radially directed thin post in a circular waveguide using the method of moments. Electric type dyadic Green's function has been used to compute the scattered field in a circular waveguide considering variation of current only in the axial direction of the post. Simulated data on return loss and power coupling in the dominant mode and higher order modes have been compared with the data computed using Ansoft's High Frequency Structure Simulator. The data on return loss and coupling for the incident ${rm TE}_{11}$ mode have been compared with experimental data.      

Analysis of an End Launcher for a Circular Cylindrical Waveguide

The analysis of an end launcher type of transition exciting dominant TE/sub 11/ mode circular waveguide from a coaxial line is presented. The expressions for real and imaginary parts of impedance seen by the coaxial line are derived for the general case of offset launcher using self reaction of the assumed current over the loop. The dimensions of combined electric and magnetic loops having low input VSWR are determined. There is satisfactory agreement between theoretical and experimental results.     

非同轴多层介质椭圆柱体的电磁散射—任意方向斜入射电磁波

本文基于椭圆柱谐基函数展开，对非同轴任意多层介质椭圆柱体的电磁散射进行了严格地电磁场分析，利用Ｍａｔｈｉｅｕ函数及其加法定理，在各层边界面上进行场的匹配，获得了任意方面斜入射电磁波下电磁散射解析解。     

Analysis of a Metal-Coated Planar Dielectric Waveguide with Chiral Cladding

The propagation characteristics of a metal-coated planar waveguide with chiral media filled in the cladding are presented. The effects of chirality on cutoff, dispersion characteristics and field distributions of the waveguide are studied. The results show that cladding chirality brings phase chopping to the transverse electric field component of those modes with odd mode numbers.     

An Improved Perturbation Analysis of a New Omnidirectional Circular Rod Antenna with Double Dielectric Gratings for Millimeterwave Application

The leakage characteristics of a new millimeter-wave omnidirectional circular rod antenna with double dielectric gratings are analyzed by an improved perturbation method. The electromagnetic fields are described in terms of a radial transmission-line network, which brings considerable physical insight into the overall behaviour of the leaky wave antenna. The analysis yields expression for the leakage constant in a closed form so that the design procedure of the antenna becomes very convenient. It is found that under the condition of the same radiation intensity, the double dielectric-grating antenna has relatively smaller dimension than that of the single one. The results obtained by the present analysis are compared with the exact solution based on the mode matching method; it is found that the improved perturbation analysis yields as accurate results as the rigorous method with extreme simplicity of the analysis and calculations.