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1.
Two methods for measuring the electromagnetic properties of materials at ultrahigh frequencies based on a dielectric resonator are analyzed. Combination of the methods makes it possible to reduce errors for measurements of material dielectric permittivity and magnetic permeability. Measurement errors are evaluated. 相似文献
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A method of measuring the dielectric properties of weakly absorbing liquids in the microwave band is proposed. The method is based on analyzing the standing-wave field for thicknesses of the liquid layers for which the conditions for total nonreflecting absorption of the incident radiation to occur in the layer of material, or conditions close to this, are satisfied. 相似文献
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微波介质谐振器介电参数的测量 总被引:6,自引:0,他引:6
本文讨论了微波介质谐振器介电参数测试技术。用研制的测试装置对多个介质样品进行了实测,结果表明,本文的分析与实际值是吻合的。该测试技术可对微波介质谐振器的复介电常数进行迅速、准确、可靠、宽频带、无损伤、自动化和批量检测,具有较强的实用性。 相似文献
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倪尔瑚 《材料科学与工程学报》1993,(2)
本文简要介绍自1970年以来得到重大发展的微波介质谐振器陶瓷,指出某些基本规律、特性及研究发展动向,也讨论了材料特征电参数间的相互依存关系。最后举例说明介质谐振器在蜂巢式便携电话中的双工器及稳频振荡器方面的应用。 相似文献
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The error of measurements of the dielectric parameters and tan in a cylindrical cavity resonator supporting the H
01p
mode by varying the length of the resonator at a constant resonance frequency is considered. The errors in measuring and tanare investigated numerically as a function of the electric thickness of the sample being investigated and its permittivity . 相似文献
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Karikh N. M. Matveichuk V. F. Sibirtsev S. N. Chernousova N. N. 《Measurement Techniques》2004,47(8):779-786
The system of metrological provisions for measuring electromagnetic properties of materials at HF and UHF within Russia, and particularly within SNIIM, is considered. The main technical characteristics of domestic standards for measuring the electromagnetic properties of materials are provided and ways for further improvement of metrological provisions for these forms of measurement at the national metrological centers in Russia are discussed. 相似文献
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研究了Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ-xTiO2(0≤2≤0.2)陶瓷的微观结构及微波介电特性.当0≤x≤10%(摩尔分数,下同)时,体系为单一钙钛矿相.随Ti4+含量的增加,B位1:2有序度下降,品质因素减小,谐振频率温度系数先由-22.6×10-6/℃增加到-11.1×10-6/℃,然后向负值方向移动.当Ti4+含量为10%时,陶瓷微波介电性能最佳:εr=29.3,Qf=2684GHz,τf=-11.1×10-6/℃. 相似文献
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The effect of high uniform pressure and temperature on the dielectric properties of productive rock of a bituminous deposit is investigated experimentally. It is found that a pressure increase results in the shift of maxima of the dielectric loss tangent towards lower frequencies, in an increase in the time of relaxation, and in a nonlinear variation of the value of permittivity. The frequency dependences of the dielectric parameters of productive rocks are characteristic of dielectrics with dipole-group processes. 相似文献
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针对金刚石膜微波介电损耗低、厚度薄带来的微波介电性能测试难点, 研制了一台分体圆柱谐振腔式微波介电性能测试装置。利用不同直径的蓝宝石单晶样品, 用上述装置对低损耗薄膜类样品微波介电性能的测试能力及样品直径对测试结果的影响进行了实验研究。在此基础上, 使用分体圆柱谐振腔式微波介电性能测试装置对微波等离子体化学气相沉积法和直流电弧等离子体喷射法制备的高品质金刚石膜在Ka波段的微波介电性能进行了测试比较。测试结果表明, 由Raman光谱、紫外-可见光谱等分析证明品质较优的微波等离子体化学气相沉积法制备的金刚石膜具有更高的微波介电性能, 其相对介电常数和微波介电损耗值均低于直流电弧等离子体喷射法制备的金刚石膜。 相似文献
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共振型进气消声器腔体尺寸对其共振频率影响研究 总被引:3,自引:0,他引:3
亥姆赫兹共振腔结构简单,且有良好的低频消声性能,近几年来广泛地应用于发动机进排气消声上.由于其消声有效带宽很窄,共振频率的精确确定直接关系到消声器能否有效消声,但是通常所采用的集中参数模型有时候会失效.建立了共振腔型消声器一维轴向声传播模型,揭示了圆形旁支型共振进气消声器的消声机理.同时对连接管长度的修正问题做了阐述,得出了共振腔一维轴向传播模型共振频率的计算公式.此外,设计了发动机进气消声器性能测试专用实验台,从实验角度研究了共振频率与腔体尺寸之间的关系.撰写为正确设计亥姆赫兹共振腔型进气消声器提供一个重要方法. 相似文献
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本文提出了复合材料等效电磁参数的FDTD计算方法,介绍了FDTD方法计算吸波材料等效电磁参数的步骤.通过对立方体模型、球形模型、连续模型和十字叉模型的仿真计算,讨论了颗粒形状和接触情况对等效介电常数的影响.通过计算不同体积分数的材料模型的等效电磁参数,得到了颗粒型复合材料等效介电常数的计算公式.通过实测复合材料的介电常数,证明了本文提出的公式是有效的. 相似文献
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Hao-Miao Zhou Fang Li Qiang Ye Ji-Xiang Zhao Zhe-Lei Xia YingTang Jing Wei 《计算机、材料和连续体(英文)》2009,13(3):235-248
At present, there are many methods about Young's modulus measurement of thin films, but so far there is no recognized simple, non-destructive and cheaper standard measurement method. Considering thin films with various thicknesses were sputter deposited on the magnetostrictive resonator and monitoring the resonator's first-order longitudinal resonant frequency shift both before and after deposition induced by external magnetic field, an Young's modulus assessing method based on classical laminated plate theory is presented in this paper. Using the measured natural frequencies of Au, Cu, Cr, Al and SiC materials with various thicknesses in the literature, the Young's modulus of the five materials with various thicknesses are calculated by the method in this paper. In comparison with the Young's modulus calculated by the other methods, it is found that the calculated Young's modulus for various thicknesses are in good agreement with the Young's modulus values in the literature. Considering the simple and non-destructive characteristics of this method, which can effectively describe the effect of the thickness on the Young's modulus, it has the potential to become a standard assessing method of thin film Young's modulus. 相似文献
15.
The complex dielectric constant (relative electric permittivity)
of liquid water was redetermined in the temperature range 0°C<;t<145°C at pressures less than 440 kPa. In this work, r was deduced from measurements of the resonant frequencies f
of a novel, re-entrant, two-mode, radio-frequency resonator. The frequencies ranged from 23 to 84 MHz and were well within the low-frequency limit for because (2f
max)2<5×10–5 where max=1.8×10–11 s is the maximum relaxation time of water under the conditions studied. The data for for two water samples differing in conductivity by a factor of 3.6 and for the two resonant modes differing in frequency by a factor of 2.6 were simultaneously fit by the polynomial function (t)=87.9144–0.404399t+9.58726×10–4
t
2–1.32802×10–6
t
3 with a remarkably small residual standard deviation of 0.0055. The present data are consistent with previously published data; however, they are more precise and internally consistent. The present apparatus was also tested with cyclohexane and yielded the values (t)=2.0551–0.00156t for 20°C<t<30°C, in excellent agreement with previously published values. 相似文献
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矩形共振腔截面纵横比对其共振频率影响研究 总被引:1,自引:0,他引:1
亥姆赫兹共振腔具有良好的低频消声性能,被广泛地应用于低频消声方面.在实际应用中,共振腔的使用往往受到安装空间的限制,有时候只能安装矩形腔.利用定体积定长度时的矩形共振腔模型,从理论上探讨了腔体纵横比对共振腔共振频率的影响.同时设计了发动机进气消声器性能测试专用实验台,从实验角度研究了腔体截面纵横比与共振频率之间的关系.理论与实验初步结果表明,在算例条件下截面纵横比对共振频率影响不大,在应用时可以不考虑纵横比问题.所讨论内容对其它条件下的研究有借鉴作用. 相似文献
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(利用虚拟仪器测试系统,对粘弹性材料力学参数进行纵向共振法测量。用激振器产生多周期正弦信号,激励棒状试样纵向振Ivibration and wave ; motorcycle ; transfer characteristic ; analysis ; test动,测量激振器输出端和材料自由端的加速度比值。通过共振频率及共振频率处加速度比的幅值,可以计算样本的杨氏模量和损耗因子。采集信号经过多次时域平均,可在最大程度上提高测试的信噪比。系统的测量结果与商用粘弹性仪结果是一致的。 相似文献