太赫兹平板材料介电常数测试技术

讨论了太赫兹波段平板材料的介电常数测试技术,在传统自由空间法原理的基础上,改进相位-群时延法解决了高频材料测试出现的多值性问题,利用介电常数及磁导率之间的震荡关系解决了厚度谐振问题,采用多项式曲线拟合的方式抑制校准误差,最后搭建了实物测试系统,对典型的空气层、聚四氟乙烯平板材料进行实验测量,实现了0.17～0.22 THz 频段范围内的2%误差测试精度。     

基于Labwindows／CVI介质复介电常数的测量系统设计

针对介质复介电常数测量自动化的需要,根据微扰法理论设计一套基于Labwindows/CVI的介质复介电常数的测量软件系统.该测试系统主要包括校准、矢网控制、计算三个模块.用户只需按照测试面板的提示即可完成对介质复介电常数洲量.井创新性地提出直接将校准文件存于计算机内,这样可以大大减少测量时的校准耗时.测量结果表明,利用该测试系统测得的数据基本与标称值吻合,且该系统操作方便,性能优良,提高了测试效率,并具有良好的扩展性.     

光纤收发器自动测试系统

针对现在光纤收发模块测试的不足,提出了光纤收发器自动测试方案,设计了光纤收发器自动测试系统.在计算机控制下实现了仪表自动控制、光路电路自动切换和数据自动检测保存,解决了人工测试仪表利用率低、误差大、工作强度高的问题,具有高度自动化、测量精确、操作简单等特点,测试速度也有了较大的提高.在介绍系统结构和工作原理的基础上,提出了改进的LOS、灵敏度优化算法及如何提高测试速度.     

基于LabVIEW的EDFA自动测试系统设计

开发了一种EDFA自动测试系统:按照时域法测量原理设计了硬件系统,利用GPIB接口对系统的各个器件进行自动控制,实现了全自动测量,提高了测试效率,降低了测试难度,减少了人为误差.系统软件采用LabVIEW编制,采用了分层模块化设计,具有高内聚,松散耦合的特点,软件的修改和维护容易,可重用性和可扩展性强.     

平板介质的微波分裂腔法介电常数测试技术

为实现微波频段平板类介质材料的介电常数的无损测试,研究了分裂式圆柱形谐振腔测试方法。介绍了分裂式圆柱形谐振腔的电磁场分析理论,采用模式匹配技术实现了介质加载条件下腔内电磁场分布的精确求解,得到了腔体谐振频率与材料介电常数之间的准确关系。在理论分析的基础上,制作了空腔谐振频率为10 GHz的分裂式谐振腔,并与前期研制的闭式谐振腔进行对比测试,介电常数实部测量结果相对误差小于1%。与国外同类产品进行对比测试,介电常数实部结果基本一致,损耗角正切测量结果更接近于文献参考值。因此,微波分裂腔法能够实现平板介质板材的无损测量,具有准确度高,使用方便等突出优势,可在微波频段内实现介电常数为1～20,损耗角正切为1×10^-3～1×10^-5,板材厚度为0.1～2.0 mm的各类平板介质材料介电常数的准确测试。     

微波陶瓷介电性能自动测试系统设计

开路型微波陶瓷材料介电性能自动测试系统的设计包括系统的测试原理、系统硬件和软件组成。利用操作界面友好的自动测试程序,可在程序面板上控制网络分析仪,实现测试数据的实时采集、分析计算与显示存储,从而提高测试效率与精度。实测表明,利用该系统能对高介电常数、低损耗的微波陶瓷材料复介电常数进行快速、准确、无损的自动测试。     

带状线法测量微波材料的复介电常数

精确测量低损耗微波材料的复介电常数十分重要。利用带状线法测量微波介质基板常温和变温的复介电常数,得到了高精度的测试结果。结果表明了用带状线法测量低损耗微波介质基板复介电常数的有效性和准确性。还分析了带状线测试方法中产生的误差和应该注意的事项。     

用于连续波腔衰荡法测量的LD驱动电路设计

为了将半导体激光器应用于连续波腔衰荡法腔损耗测量,设计了半导体激光器的驱动电路.该电路由调制、驱动、温控等模块组成,在采用多光束干涉理论对连续波腔衰荡法测量原理进行分析和数值模拟的基础上,提出了驱动电路各模块的参数要求,对该电路各参数进行测试后,应用该电路建立了连续波腔衰荡法腔损耗测量系统,并进行了实验.经测试得知,在保证半导体激光器安全工作的前提下,该电路对于半导体激光器的关断时间约为60ns,对半导体激光器的温度控制精度优于0.01℃;对某单程腔损耗约为50×10-6的衰荡腔测试表明,腔损耗测量精度优于1%.结果表明,该电路达到理论设计要求,可应用于高精度腔损耗测量.     

LXI-测试自动化的未来

1.测试自动化技术的应用 自动测试系统,无论是在航空航天和国防电子领域,还是在消费类电子产品的生产线测试和质量验证,都有着非常广泛的应用.由于自动测试技术的引入,不仅能提高测试效率,保证测试的准确性和可信度,减少由于人为原因造成的测量错误和误差,降低生产和测试成本,而且还可以对测试数据和结果进行信息化管理.无论是在整机,元器件或模块的指标和功能测试,老化及可靠性等测试中,自动测试技术都有着广泛的应用.     

微带线法测量介质材料的高温介电常数

微波介质材料的电磁参数决定了其在各领域的应用性能。为探索高温条件下介电常数的变化趋势,文章讨论了设有空气隔热层时的微带线法测量原理,分析了微带线法测量不确定度的影响因素。完成了介质材料1~40 GHz的常温、高温介电常数测量,并对测量结果的不确定度进行评估。测量结果表明:20 GHz以上,介电常数的相对不确定度略有增加,微带线法的测量结果较为准确。     

Open Resonator System for Automatic and Precise Dielectric Measurement at Millimeter Wavelengths

As low loss dielectric materials, ZnS, MgF₂, MgAl₂O₄ and quartz ceramic have a very important application at millimeter frequencies. However, there is little information about their dielectric properties in the millimeter wavelength band. To obtain their dielectric properties, an automatic open resonator measurement system at Ka-band is designed and constructed. The importance on the precision determination of cavity length over a broad band and the checking of a measurement system are emphasized and their solutions are put forward in this paper for the first time so far as we know. The solutions of above problems ensure the credibility and high accuracy of our measurement system. The certified measurement system after a series of checking is used to measure the above materials. Lots of measurement results show that the standard deviation of measurement error is less than 0.154% in permittivity and 20.42% in loss tangent. Meanwhile, some experimental summaries on the open resonator technique are provided. Software that controls the measurement system is developed and it improves the testing efficiency greatly.     

New Methods of Dielectric Measurements in the Millimeter-Wave Band

A heterodyne interferometer was constructed in the V-band at 60GHz to measure the phase difference associated with the material. This phase difference is then used to calculate the real part of the dielectric constant from the index of refraction. Measuring equipment for monitoring the permittivity and loss of a medium in the millimeter-wave band (gamma = 3.5 mm) is developed. The measurement error of the equipment using the reflection method is less than 2%. A new spectrometer for the precision measurement of dielectric permittivity and loss tangent, which is capable of providing high resolution data for the first time over an extended W-band (68-118GHz) frequency for specimens with a large range of absorption values, including highly absorbing specimens that otherwise would not be possible.     

测量低损耗薄膜材料介电常数的标量法

依据被测介质性质,在现有实验设备条件下,提出了一种标量法测量低损耗薄膜介质介电常数的新方法.该方法利用传输线法测量原理,先测量待测介质损耗,间接得到反射系数,由反射系数与介电常数关系式,推导得出待测介质的介电常数.该方法有样品容易制作,测量简单准确等特点.通过测量实例的误差分析,指出标量法测量薄膜材料介电常数的不足,提出相应的改进措施.     

A new tool for accurate S-parameters measurements and permittivity reconstruction

In this paper, we present a tool for permittivity reconstruction. The tool consists of a coaxial transmission line and a novel analytical reconstruction technique. The line is designed for accurate permittivity measurements of soil samples. It allows for single or double phase flow. The full S-parameter matrix is modeled with transmission line theory. We show that for accurate measurements each component of the tool needs careful calibration. We give a method to compute the sensitivity of these measurements to different materials, and we show the accuracy in the determination of the sample permittivity from the measurements based on deviations of the forward model compared to measured results as a function of the error in the sample permittivity. We demonstrate that a maximum error of less than 1% is obtained for the possible permittivity reconstruction from these measurements for wavelengths less than five times the sample holder length. The novel reconstruction technique is based in the propagation matrices method. It consists in rewriting the transmission line model in matrix notation and relating the S-parameters to the total reflection and transmission of the line seen as a two-port network. Thanks to this novel approach, the reconstruction of both permittivity and permeability can be done directly from the measured S-parameters of the line. Due to experimental instabilities the errors are considerable, and we must restrict ourselves to the reconstruction of permittivity. Results on an air sample are within the predicted error of 1%. Computing relative errors for an ethanol sample is not possible due to temperature and purity difference between our experiment and published results; nevertheless, the reconstructed permittivity of ethanol follows the Debye model.     

Preliminary Observations with an Electromagnetic Method for the Noninvasive Analysis of Cell Suspension Physiology and Induced Pathophysiology

A technique for the electromagnetic analysis of physiological and patho-physiological states in cell suspensions is presented. The technique is based upon high speed automatic network analysis in the HF band for measurement of complex permittivity. The results demonstrate that changes in HF-band permittivity dispersion may be related to physiological and drug-induced patho-physiological states of the cell membrane. Mechanical disruption of the cell membrane by sonication obliterates the HF-band dispersion of permittivity that is present in undisrupted cells. The effect of species, suspending medium, and temperature were systematically analyzed in erythrocyte suspension in order to aid comparison between published studies of red cell preparations.     

针对太赫兹波段介电参数测量的宽带准光系统

该文针对太赫兹波段材料的介电参数提取的需求,利用准光学技术设计了一套宽带介电参数测量系统并讨论了自由空间的介电参数提取方法。通过平面扫描的方法验证了系统电磁传输特性。结果表明,准光系统的近场参数与设计结果相吻合。利用石英硼化玻璃和水样品进行了测试,并利用数值方法对介电参数进行提取。测试结果表明,利用准光方法测试所得到的介电参数与典型值相吻合,进一步验证了该方法的有效性。      

基于声光偏转的载频相干探测研究

基于声光偏转和相干光探测原理,构建了频率测量系统.从改善空间光相干探测效率出发,提出一种将空间光经声光偏转后注入保偏光纤的信号处理方法,并具体讨论了如何利用准直-聚焦透镜的注入系统保证带宽内信号光的注入效率.实验结果表明,此测频系统能准确、实时测量信号的频率,在测频带宽内其截获率达到100%.     

Improved technique for determining complex permittivity with thetransmission/reflection method

The transmission/reflection method for complex permittivity and permeability determination is studied. The special case of permittivity measurement is examined in detail. Robust algorithms for permittivity determination that eliminate the ill-behaved nature of the commonly used procedures at frequencies corresponding to integer multiples of one-half wavelength in the sample are presented. An error analysis yielding estimates of the errors incurred due to the uncertainty in scattering parameters, length measurement, and reference plane position is presented. Equations for determining complex permittivity independent from reference plane position and sample length are derived