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讨论H01型圆柱谐振腔的测试原理;详细介绍了用圆柱谐振腔测量介质材料相对介电常数及损耗角正切的方法. 相似文献
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材料的介电特性是器件和电路设计的基础。随着设计频率进入太赫兹频段,材料特性变得未知,缺乏相应的测
试数据。利用太赫兹时域光谱(THz-TDS)技术对常用的材料进行测试并给出相应的测试结果。首先给出了材料特性测量的
原理与计算公式,并利用该方法对微波板材Rogers RT/Duroid 5880,FR4_epoxy 及不同电阻率的硅基材料在太赫兹频段的介质
特性进行了测量和实验分析,得出了这4 种材料在太赫兹频段的相对介电常数及损耗角正切。其中,高阻硅的损耗最低,其次
为Rogers RT/Duroid 5880 板材,而FR4_epoxy 板材则在0.3~0.4 THz 存在明显的吸收峰。最后,讨论了这些材料在太赫兹频段
的应用前景。 相似文献
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本文从时谐电磁场情况下电介质的电极化物理过程出发,通过理论推导建立了介质损耗与复介电常数的关系。在此基础上,以电容器为例得到了时谐情况下的等效电路,进一步得到电容器中电介质的复介电常数实部和虚部与频率的关系,并通过指导本科生测量电介质介质损耗角正切得到复介电常数的频率特性。 相似文献
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本文讨论了在液氮温度下高温超导微波电路介质衬底材料复介电常数测试技术。利用TMono模高Q圆柱形谐振腔,对高温超导常用的几种单晶介质材料进行了测试。结果表明,该测试技术在不同温度下,可对低耗单晶和各向同性介质材料进行准确的测试,且测试简便、迅速、自动化程度高,具有测试介质材料某一方向复介电常数的优点。 相似文献
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根据微波谐振腔的谐振频率随腔内溶液的介电常数的变化而发生偏移的特性,本文设计了基于微波谐振腔的葡萄糖溶液浓度测量系统,包括谐振腔测量模块、谐振频率跟踪模块和等精度频率测量模块,可实现对溶液浓度的实时测量。谐振频率跟踪模块利用单片机控制压控振荡器(Voltage Controlled Oscillator,VCO)的输出频率,使VCO的输出频率与谐振频率实时保持一致,实现了谐振频率的自动跟踪。等精度频率测量模块在标准频率为50 MHz时,误差达到2×10-8,浓度测量分辨率达到0.01mmol/kg。 相似文献
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介质材料的相对复介电常数可以用ε_r=ε(1-jtgδ)表示,式中ε为相对介电常数,tgδ为损耗角正切.我们在日常科研和生产中经常用到某些陶瓷、塑料或玻璃钢等介质材料,它们的相对介电常数小于10,损耗角正切小于0.1,可以称之为低介电常数、低损耗介质 相似文献
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液晶材料在微波频段具有良好的调制特性,在微波可调谐器件领域具有巨大的应用潜力。本文针对液晶材料微波介电常数的测量需求,提出了一种基于人工局域表面等离激元谐振的传感器。通过设计环形谐振器结构,在sub-6 GHz频段形成局域表面等离激元窄带谐振峰。通过给液晶施加外加电场,能够实现对液晶介电常数的调控。通过谐振频点位置的拟合,能够得到对应的液晶的介电常数大小,从而实现液晶材料在微波频段的介电常数的测量。本文研究了不同液晶层厚度、不同液晶介电常数对人工局域表面等离激元谐振频点的影响。随着液晶层厚度增加或者液晶介电常数的减小,谐振频点f1和f2都逐渐增大。当液晶层厚度大于或等于0.5 mm时,谐振频点f1和f2随介电常数的变化具有良好的线性度,且具有高灵敏度(>400 MHz/Δε),远大于基于目前报道的其他形式介电常数传感器。同时,本传感器结构可以在液晶层上下施加电场,从而实现在不同外加电场作用下液晶材料微波介电常数的测量,在液晶微波特性研究领域具有应用潜力。 相似文献
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A novel technique for the measurement of dielectric properties of a homogeneous isotropic material is described. An accuracy better than 1% can be obtained on the permittivity and loss tangent values. The structure used is a cylindrical metallic cavity, carrying at its centre the circular cylindrical dielectric sample. The complex permittivity is deduced from the comparison between the experimental and the computed electromagnetic characteristics (frequencies, quality factors) of the resonant TE01? mode of the dielectric resonator. 相似文献
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An effective dielectric constant technique to determine the resonant frequency of the TE01δ mode of a cylindrical dielectric resonator placed in a microwave integrated circuit (MIC) environment is discussed. An expression for the dielectric constant εeff which makes it possible to obtain results that compare favorably with rigorous methods is given. Experimental results demonstrating the method's validity are also reported. For a given resonant frequency, closed-form expressions for computing the height of the resonator are given 相似文献
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Rajab K.Z. Fuh K.-F. Mittra R. Lanagan M. 《Microwave and Wireless Components Letters, IEEE》2005,15(2):104-106
This letter describes a new dielectric characterization technique, based on the resonant nonradiative waveguide structure described by Yoneyama and Nishida , for permittivity measurements at microwave and mm-wave frequencies. The measurement system is modeled as a resonator comprised of two parallel conducting plates with a rectangular dielectric slab sandwiched in-between. Resonant frequencies of the longitudinal section electric (LSE) modes and the unloaded Q of the cavity are used to determine the permittivity of the dielectric and its loss tangent, respectively. The technique is shown to be accurate for measuring the dielectric properties of a wide array of polymer and oxide materials. For materials with small dielectric loss tangents, an accuracy of better than /spl plusmn/0.4% is attained in the measurement of the relative dielectric constant of the material. 相似文献
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《Microwave Theory and Techniques》1960,8(6):650-653
The measurement of complex permittivities of isotropic media at microwave frequencies is performed with high precision by means of cylindrical cavity resonators. However, a hole in the cavity wall, for inserting the sample causes a frequency pulling of the resonator, which in turn introduces an error in the measured dielectric constant. These effects are measured, and with perturbation theory as a guide, correction factors are developed. 相似文献
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《Microwave Theory and Techniques》1972,20(3):233-235
A technique is presented for accurately determinhg the dielectric constant of microwave materials. The concept is to resonate a cutoff circular-waveguide cavity by inserting the dielectric-disk sample. Unlike most dielectric measurement techniques which rely on perturbation methods, this one determines the dielectric constant from the absolute measurement of the resonant frequency. Also, the use of a cutoff cavity prevents false dielectric constant readings by eliminating spurious resonances. 相似文献
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《Microwave Theory and Techniques》1986,34(9):923-931
An analytical expression is given for the resonant frequency of a rectangular patch antenna. It shows explicitly the dependence of the resonant frequency on the characteristic parameters of a patch antenna. Based on this result, a new method is developed for the measurement of the dielectric constant of a thin slab substrate. Basically, the test equipment consists of a rectangular microstrip antenna the patch of which is fed either by a microstrip line or coaxial line. From the measured resonance parameters of the rectangular patch antenna, the dielectric constant can be easily obtained. The measured values of the present method are in agreement with the precision standard cavity resonator method. Accuracy of the dielectric constant so obtained is satisfactory. 相似文献
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Daiqing Li Free C.E. Pitt K.E.G. Barnwell P.G. 《Microwave and Wireless Components Letters, IEEE》2001,11(3):118-120
A simple yet rigorous method has been developed to enable the loss tangent of dielectrics, having a known relative permittivity, to be accurately measured using a waveguide resonant cavity. The novel method eliminates the need for any physical measurement, either on the cavity or dielectric sample under test. The only electrical parameters that need to be measured are resonant frequencies and Q-factors of a reference cavity and those of the same cavity loaded with the dielectric sample. One of the advantages of the new technique is that dielectrics, of arbitrary shape, can be characterized at very high microwave frequencies. The new method has been verified through measurement over X-band 相似文献
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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 相似文献
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Determination of Complex Permittivity of Arbitrarily Dimensioned Dielectric Modules at Microwave Frequencies 总被引:3,自引:0,他引:3
《Microwave Theory and Techniques》1971,19(6):517-521
A method of evaluating the microwave dielectric properties of any geometrically defined sample is described by general theory and through experimental verification. The typical mathematical relations that describe specimen loss tangent by cavity methods are uniquely modified through inclusion of the derivative of cavity resonant frequency with respect to dielectric constant of the material comprising the particular configuration studied. The dielectric modules under study need not meet the small volume requirements demanded by perturbation theory; they may even occupy a very large volume of the cavity. A particular advantage of the described evaluation technique is the continuity of use of a given dielectric specimen for tests at microwave frequencies, without geometric alteration, after its properties at lower frequencies have been determined. 相似文献
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Cylindrical Dielectric Resonators and Their Applications in TEM Line Microwave Circuits 总被引:3,自引:0,他引:3
《Microwave Theory and Techniques》1979,27(3):233-238
A cylindrical sample of low-loss high epsilon/sub r/ placed between two parallel conducting plates perpendicular to the sample axis forms a microwave resonator. A simple approximate method for predicting the resonant frequencies of the TE modes of this structure is developed. The method becomes exact for the fitting case of this structure which is known as a dielectric post resonator. In all cases, the accuracy of the method is shown to be better than 3.5 percent. The TE/sub 01delta/ mode chart presented allows the determination of the resonant frequency and the tuning range of any cylindrical dielectric resonator for which epsilon/sub r/ >or= 10. The properties of the dielectric resonator as a TEM line element are demonstrated experimentally. 相似文献