Resonant Frequency and Q of an Open-Ended Rectangular Cavity

A field analysis of the TE /sub 10m/ resonant mode in an open-ended rectangular cavity is presented. The cavity geometry consists of rectangular waveguide with thick H-plane bifurcations for the terminations at each end. The bifurcation problem is solved by the method of modal analysis and a resonance criterion is established. Expressions for the cavity fields are written and used to compute stored energy, power lost, and Q. Calculated values for resonant frequency and Q are given and compared with experimental data.     

On the Resonant Frequency of a Reentrant Cylindrical Cavity

A new efficient method determining the resonant frequency of a reentrant cylindrical cavity is suggested. The method is based on solving the Helmholtz equation within two cavity regions and matching the solutions across the boundary surface. Contrary to similar formulations published previously, the continuity conditions on the boundary are imposed in a rigorous way. As a result the solution is obtained in a form of succesive approximations converging to the exact resonant frequency when a number of iterations tend toward infinity. Numerical examples are given for a few reentrant cavities of typical dimensions. Comparison is also made with experimental data as well as other theoretical results.     

The Resonant Frequency of a Narrow-Gap Cylindrical Cavity (Letters)

A recently proposed method for computing the resonant frequency of a narrow-gap reentrant cylindrical cavity is discussed. It is shown that provided that the cavity does not have too low a height-to-diameter ratio, its resonant frequency may also be computed with expectation of reasonable accuracy from numerical data which have been available in the literature for some time.     

The Resonant Frequency and Tuning Characteristics of a Narrow-Gap Reentrant Cylindrical Cavity

The literature concerning the reentrant cylindrical cavity is reviewed and the relative advantages and disadvantages of the various formulations of the problem are discussed. In addition, a new formulation is proposed which accurately predicts the resonant frequency of narrow-gap cavities such as those currently finding application in the construction of solid-state oscillators. This new formulation is mathematically simpler and numerically more efficient than many other formulations which are not as accurate. The paper concludes with an investigation of the toning characteristics of the cavity.     

Discussion of "The Resonant Frequency and Tuning Characteristics of a Narrow-Gap Reentrant Cylindrical Cavity" (Letters)

After programming the working equations given in the Appendix to this paper, and finding that I could not reproduce the numerical results given in Table I, I have corresponded directly with the author. He informs me that there are four errors in the equation given on p. 187.     

Measurement of Short Time Changes of Cavity Q and Resonant Frequency

A method for the determination of short time changes of Q factor and resonance of a cavity has been developed. The method is based on the observation of the change in reflection coefficient. As long as the cavity is coupled undercritically there always exist two frequencies at which no change of the reflection coefficient occurs. The measurement of these frequencies is sufficient for evaluating the changed values of the unloaded Q and the resonant frequency assuming no change of the external Q during perturbation. This assumption can be made in most cases of application. If there also exists a perturbation of the external Q, the value of the changed reflection coefficient must be measured at any additional freqnency preferably at the resonant frequency of the unperturbed cavity. Experimental results demonstrate the applicability of this method.     

Design of Open-Ended Microwave Resonant Cavities (Correspondence)

This paper summarizes a Ph.D. dissertation on the design and analysis of open-ended microwave cavities. The study was motivated by the need for a cavity with a high measure of quality, Q, through which an unobstructed flow of gases or particulate matter could be obtained. Used in collection with the Crain refractometer, instantaneous measurements of the refractive index of the material in the cavity can be made. Measurements utilizing his technique but with other types of cavities have previously been made in order to study the dielectric properties of smoke and other aerosols.     

有孔圆柱介质谐振频率的自动测试方法

从求解Maxwell方程本征值出发,采用MATLAB中PDE工具箱,借助可二维作图的开槽圆柱谐振器,计算出有孔圆柱介质谐振器的谐振频率。求解结果与矢量网络分析仪测量结果吻合,误差在千分之四以内。且该有限元法计算软件采用MATLAB编写,可方便地被调用于矢量网络分析仪的VEE测试软件中,较好解决有孔及变形圆柱介质谐振器的设计、测量和微调等问题,特别是矢量网络分析仪的快速自动测量中。     

Theoretical and Experimental Study of the Resonant Frequency of a Cylindrical Dielectric Resonator

A rigorous modal method is described for calculating the resonant frequencies of a circular cylindrical dielectric rod placed between two perfectly conducting plates. Comparisons of the numerical results with those obtained from another rigorous theory developed at the same time by one of the authors show an accuracy better than 10/sup -4/. Comparison with experimental data shows generally a very good agreement.     

气体激光器圆柱形微波激励谐振腔的微扰理论分析及其应用

导出了工作于ＴＭ０１０模的圆柱形微波等离子体腔中等离子体与腔谐振频率关系的精确解析式和微扰近似公式，比较结果表明：在微波激励低气压气体激光器中微扰理论可相当精确地分析微波等离子体对腔的扰动效应。给出了消除等离子体与管壳的扰动引起的腔失谐的方法，从而在气体激光器中成功地形成了稳定与均匀的微波等离子体和稳定的激光输出。用微扰理论使此腔又具有测量等离子体电子密度和管壳微波介电常数的功能     

Resonant Cavity Type Mode Transducer

This paper describes the operating principle and the properties of a resonant cavity type mode transducer which was newly devised. The theoretical equations necessary for designing the mode transducer from a TE/sub 10/ mode of a rectangular waveguide to an arbitrary mode of a circular waveguide have been derived, and a design method using the coupling parameters is discussed. The experiments were made for the rectangular TE/sub 10/-circular TE/sub 01/, mode transformation in the 50 Gc band. Showing an example (N=1), the transfer loss, input SWR and mode purity were 1.34 dB, 1.13, and 95 percent (power contents), respectively, at the resonant frequency of 50 Gc/s. The 3 dB bandwidth of the transfer loss was 83 Mc/s at the constant cavity length, but it can be made much larger if the cavity length is adjusted according to the frequency change. This mode transducer is unique in that various modes can be excited purely in the circular guide by merely varying the cavity length.     

谐振腔增强型光探测器的高速响应性能研究

高速长波长光探测器是高速光纤通信系统和网络的关键器件，它要求光探测器具有宽的频率响应带宽和高量子效率。常用的PIN光探测器由于量子效率和高速性能均受到吸收层厚度的牵制，使得二者相互制约，成为一对矛盾。谐振腔增强型(RCE)光探测器为这一矛盾的解决提供了有效的方案。基于谐振腔增强型光探测器的实际设计和制作模型，分析了器件吸收层中的光场分布，并将其运用于载流子的连续方程，从理论上详细地分析了器件的高速响应特性，给出了计算结果。针对研制的高速长波长谐振腔增强型光探测器，进行了理论分析和实际器件测试的结果比较，得到了比较一致的结果。     

激光谐振腔的单片机精密控制系统

本文介绍了一种在单片机控制下能实现对大功率CO2 激光器光腔进行精细调节的装置。介绍控制系统的重要硬件与软件设计与实验研究等。这是一个简单实用的控制系统。     

Lumped Parameters of a Reentering Cylindrical Cavity

The cylindrical reentering cavity is studied. It is shown how lumped equivalent parameters can be known that are one inductance and two capacitances. These elements can be measured experimentally. Thus the problem of coupling with an active solid-state element, defined itself by lumped equivalent parameters (inductances and capacitances), is accurately solved.     

圆柱凹型腔的分析与应用

本文对典型圆柱凹型腔进行了系统的电磁分析，根据横向谐振原理，给出了谐振频率的计算方法，分析了不同的谐振模式，计算了腔体的Ｑ０值。为工程设计编制了调谐特性的计算机软件，实现了腔体在３ｍｍ谐波振荡器中的应用。     

Analysis of Circular Cavity With Cylindrical Objects

This paper presents the analysis of electromagnetic wave scattering by cylindrical objects located arbitrarily in a circular cavity. The exact full-wave theory based on the mode-matching method is applied to analyze the structures. The resonance frequencies of the investigated resonators are accurately determined. The validity and accuracy of the approach are verified by comparing the results with those obtained from alternative numerical methods and the authors' experiment.     

用于共振腔光电探测器的Si基Bragg反射器

Si基共振腔型光电探测器的关键工艺是隐埋Bragg反射器镜面的制备.用PECVD方法在Si衬底上制备了SiOxNy/Si Bragg反射器,研究了Bragg反射器的反射谱和退火行为.     

用于共振腔光电探测器的Si基Bragg反射器

Si基共振腔型光电探测器的关键工艺是隐埋Bragg反射器镜面的制备.用PECVD方法在Si衬底上制备了SiOxNy/SiBragg反射器,研究了Bragg反射器的反射谱和退火行为.     

激光谐振腔的自动控制系统

文中介绍了激光谐振腔的控制系统设计。