Microwave Measurement of Conductivity and Permittivity of Semiconductor Spheres by Cavity Perturbation Technique

Simple analytical relations for evaluating the components of complex relative permittivity of semiconductors using a cavity perturbation technique for spherical samples are presented. The relations although derived under a simplifying approximation yield remits of almost the same accuracy obtained by computer solutions of a transcendental equation for samples with resistivity up to about 1Omega-cm.     

Cavity Perturbation Techniques for Measurement of the Microwave Conductivity and Dielectric Constant of a Bulk Semiconductor Material

Cavity perturbation techniques offer a very sensitive highly versatile means for studying the complex microwave conductivity of a bulk material. A knowledge of the cavity coupling factor in the absence of perturbation, together with the change in the reflected power and the cavity resonance frequency shift, are adequate for the determination of the material properties. This eliminates the need to determine the Q-factor change with perturbation which may lead to appreciable error, especially in the presence of mismatch loss. The measurement accuracy can also be improved by a proper choice of the cavity coupling factor prior to the perturbation.     

改进矩形腔微扰法测试微波电介质复介电常数

本文讨论了测试电介质微波复介电常数的矩形腔微扰法。对介质样品加载后的ＴＥ１０ｎ模矩形腔腔内场进行了理论分析。通过对腔内场的数值求解，得出了与微扰公式相似的、已修正的准确计算公式。     

Measurements of Microwave Conductivity and Dielectric Constant by the Cavity Perturbation Method and Their Errors

The theory and technique of the cavity perturbation method for measuring the conductivity and dielectric constant of materials are reviewed. An analytical formula for calculating the errors of the conductivity and dielectric constant caused by the measured error in the resonant frequency and quality factor are derived. This formula can be used for both rectangular and cylindrical cavities. The results of measurements on silicon samples are presented to illustrate this analysis.     

High-Accuracy Wide-Range Measurement Method for Determination of Complex Permittivity in Reentrant Cavity: Part A --- Theoretical Analysis of the Method

New mathematical method for calculation of complex electric permittivity (epsilon) of a wide range of materials from the direct measured parameters of a reentrant cavity containing a sample of material is presented. Condition of resonance is drawn based on analysis of electromagnetic field distribution in the cavity with a sample. Accuracy of the obtained algorithm (convergences of series) and method of shortening iterative solution is discussed in detail.     

微波腔体微扰方法测量非电量技术

本文简述微波腔体微扰方法测量湿度、厚度等非电量的原理.根据电磁场理论,导出分辨率公式.计算及实验均表明,用微波腔体微扰方法测量非电量具有高的分辨率.文中还介绍几种检测腔体失谐的方法,着重讨论了鉴相方法和实验结果.     

High-Accuracy Wide-Range Measurement Method for Determination of Complex Permittivity in Reentrant Cavity: Part B -- Experimental Analysis of Measurement Errors

In Part A, the measurement method of epsilon was presented from the mathematical viewpoint. Experiments undertaken in this section were carried out in order to illustrate the theorical thesis of Part A, as well as to verify the postulated calculation method and analyze measurement errors.     

Electrical Conductivity Measurement Through the Loaded Q Factor of a Resonant Cavity

We present a method for measuring the electrical conductivity of metallic materials that relies on the ratio of two loaded Q factors, Q_R/Q_X, with Q_R corresponding to a TE₀₁₁-mode reference cavity made of aluminum, and Q_X the Q that results upon replacing the aluminum plate with the one fabricated from the material to be examined. Electrical conductivity is mathematically inferred from the ratio Q_R/Q_X where the loaded Q factors are measured by using the transmission-type method. Within a 3.0 percent accuracy, conductivities determined at 8.7 GHz for electrolytic copper (5.6 times 10⁷ S/m) and brass (1.6 times 10⁷ S/m) show to be in good agreement with those reported in the literature.     

铁电材料介电常数的测量方法研究

描述了一种基于同轴谐振腔技术测量铁电材料介电常数的原理和方法。将待测样品放置在1/4波长的同轴谐振腔的开路端,通过设计制作尺寸合适的同轴谐振腔以保证在测量频率范围内只存在横向电磁场(TEM)基波,并根据测量的同轴谐振腔TEM基波的谐振频率,计算出相应的样品介电常数以及介电常数随电压的变化。为了精确采样待测样品和同轴谐振腔开路端之间部分所形成的等效电容,分析了电容边缘效应并结合边界元数值算法计算该等效电容。针对主要误差来源(气膜),采用在样品上用导电胶制作电极从而减小气膜对测量的误差影响。实验结果表明这是一种简便而有效的测量铁电材料介电常数的方法。     

A Measurement of the Complex Permittivity Tensor by a Standing-Wave Method in a Rectangular Waveguide

A rubber sheet manufactured by the rolling process strongly shows an anisotropic property, which is caused by carbon particles or carbon fibers aligned along the rolling direction. The measurement of the complex permittivity tensor in the rubber sheet is studied by a standing-wave method in a rectangular waveguide. The tensor elements, including nondiagonal and principal-direction ones, are measured and discussed. Errors in the measured tensor elements are evaluated.     

电磁开腔测量双层介质复介电常数

本文提出了一种利用电磁开腔在微波和毫米波频段测量双层介质复介电常数的新技术。在８ｍｍ频段，利用一套电磁开腔自动测量系统对几种双层介质材料进行了具体测量。最后，对测量误差进行了理论分析，并给出了计算实例。     

外腔半导体激光器的场功率谱和线宽

本文采用低频近似的方法,用半经典理论,给出了外腔半导体激光器的场功率谱和线宽公式,理论分析与实验结果是吻合的。     

电磁开腔测量多层介质样品复介电常数

本文提出了一种在毫米波和亚毫米波微段利用电磁开腔测量多层介质样品复介电常数的新方法。在ｋａ波段利用特制的开腔装置建立了一套电磁开腔电介质参数测量系统，并对一些多层介质样品进行了实际测量。测量结果与标称值十分吻合。     

Extension of Digital Automatic Method for Measuring the Permittivity of Thin Dielectric Films (Short Papers)

The permittivity of thin dielectric films can be measured with good accuracy by employing a method recently reported by the authors, whereby the microwave oscillator frequency is automatically locked to the resonant frequency of the test cavity perturbed by the sample, thus leading to a digital readout of the frequency. However, the method is satisfactory only when the frequency shift caused by the presence of the test sample does not exceed the frequency lock-in bandwidth. By employing a search oscillator, controlled by the second harmonic of the modulation signal provided for the frequency locking, this limitation is removed, thus extending the capability of the method to thicker films and/or larger permittivities.     

Measurement of Semiconductor Laser Gain by the Segmented Contact Method Under Strong Current Spreading Conditions

A segmented contact method for the measurement of optical gain is developed for the case of strong current spreading. A simple model of current spreading in a ridge laser with a segmented contact is proposed and analyzed. We show that current spreading effects should be taken into account in lasers with low threshold current densities and high ldquoopeningrdquo voltages. When applied to interband cascade lasers, the method gives an internal optical loss of ~ 10-17 cm^-1 and a differential gain of ~ 2.9 cm/A at 80 K, which agrees well with previously reported Hakki-Paoli data. The limitations of the technique are discussed.     

光栅外腔主动锁模半导体激光器特性研究

本文对光栅外腔主动锁模半导体激光器输出脉冲及其光谱进行了详细的实验研究.对影响完全锁模光脉冲宽度的若干因素进行优化组合,由正弦调制的普通DH-GaAlAs光栅外腔激光器得到了最短光脉冲宽度为8.2ps,重复频率为961.06MHz,峰值功率大于150mW,谱调谐范围大于10nm的锁模输出.     

Permittivity and Conductivity Measurements of Building Materials at 5.8 GHz and 41.5 GHz

The results of various experiments performed to characterize electromagnetic properties of typical building materials at BRAN (Broadband Radio Access Networks) and MVDS (Multipoint Video Distribution System) bands are presented and compared. Transmission and reflection coefficients were measured as functions of the angle of incidence, using a wideband sounder based on the swept frequency technique. A high precision angular positioning system was built and used in co-ordination with the measurement equipment.The dielectric constants (_r) were estimated by comparing values predicted with a multiple successive internal reflection model and measured transmission and reflection coefficients. It has been found that the variation of the dielectric constant value with the frequency does not necessarily follow the same trend for different materials. For example, the measured _r for plasterboard presents an increment withfrequency (2.02 at 5.8 GHz, 2.5 at 41.5 GHz – measured by theauthors –, 2.58 at 59.5 GHz, and 2.81 at 60.2 GHz – given byliterature –), while the values for glass follow a wanderingpattern (6.06 at 5.8 GHz, 5–10 at 10 GHz, 3.41 at 41.5 GHz, 7.51at 57.6 GHz, and 5.29 at 60.2 GHz). Moreover, the measured_r for a brick wall at 5.8 GHz (3.58) shows differenceswith values reported at 2 GHz (4.44).     

外腔半导体激光器的理论分析与试验

对描述外腔半导体激光器的多模速度方程组作了适当修正,利用经修正的多模速度方程组,对外腔半导体激光器的选模特性,输出功率及稳频进行了理论分析;从实验上观察了p=1.3um的外腔单纵模的工作情况;模抑制比S0/S1<280,实验结果与理论分析基本一致.     

腔衰荡法四腔镜反射率及腔内吸收测量

利用腔衰荡四腔镜轮换的方法 ,在常态下测得了四腔镜的反射率 ,同时得到了腔内对测量光的吸收损耗     

腔衰荡法四腔镜反射率及腔内吸收测量

由于镜片的反射率在不同的环境中是不同的,我们在这里利用腔衰荡四腔镜轮换的方法,在常态下测得了四腔镜的反射率,同时得到了腔内气体在测量范围的吸收情况。