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研发了一套利用散射参数法测量材料电磁特性的自动测试系统,其配套软件功能强大完善且完全商业化,可以快速有效地测量正切损耗角大于0.1的微波材料的复介电常数与导磁率等10项特性参数.首次提出了“尝试-比较”法,以实验结果证明了其有效性,解决了长期存在的求解多值性难题,进一步完善了散射参数法. 相似文献
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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。 相似文献
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本文提出了一种新的确定Ka 波段毫米波损耗材料复介电常数和磁导率的测量方法,给出了确定样品的复介电常数和磁导率的散射方程。与传统采用的NRW 方法相比,这一方法消除了介电常数测量对参考面的位置和样品长度依赖性。 相似文献
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本文导出了双层复介电常数圆柱体散射场的矩阵解公式,并用所模拟的散射场定量研究了用滤波-反投影技术计算出的介质柱内部介电常数分布特性。文中给出了介质圆柱的二维径向分布曲线以及由重构图象矩阵中统计回收计算出的介电常数损耗。 相似文献
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用自由空间法测试介质电磁参数 总被引:6,自引:0,他引:6
提出了一种测试介质材料微波复介电常数和复磁导率的新方法;建立了测试方法的物理模型;通过理论分析,获得了求解被测材料微波电磁参数的计算表达式;研制了测试装置和测试系统,讨论了用于测试系统的校准方法和提高测试准确度的时域门技术.在8~12GHz的频带范围内,对多种介质材料进行了实测,结果表明,本文提出的测试方法和研制的测试系统是正确可靠的,具有实用价值. 相似文献
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《Microwave Theory and Techniques》1960,8(2):155-159
This paper describes a graphical method for measuring the real and imaginary parts of the dielectric constant epsilon/epsilon/sub 0/ = epsilon' - j epsilon" of materials at microwave frequencies. The method is based on the network approach to dielectric measurements proposed by Oliner and Altschuler in which the dielectric sample fills a section of transmission line or waveguide. In contrast to their method, the network representing the dielectric sample is analyzed in terms of the bilinear transformation Gamma'=(aGamma+b)/(cGamma+d); ad-bc=4. The analysis proceeds from the geometric properties of the image circle in the r plane obtained by terminating the output line in a calibrated sliding short. The technique described retains the desirable features of the network approach but avoids the necessity of measuring both scattering coefficients. As a result the procedure is more direct and, in the case of the TEM configuration, leads to an entirely graphical solution in which the complex dielectric constant can be read from a Smith chart overlay. 相似文献
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《Microwave and Wireless Components Letters, IEEE》2009,19(12):801-803
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The iterative forward-backward (FB) method is a recently proposed efficient technique for numerical evaluation of scattering from perfectly conducting rough surfaces. Extension of the method to include scattering from imperfect conducting surfaces, with a high imaginary part of the complex dielectric constant, has also been proposed. The FB method is further generalized to analyze scattering from dielectric rough surfaces with arbitrary complex dielectric constant. Electric and magnetic equivalent surface currents are split into forward and backward components and equations governing these current components are obtained. As a solution, an iterative scheme is proposed and its convergence rate is analyzed. Finally, the effectiveness of the method is assessed by comparing the obtained scattering results with "exact" ones, computed by employing the usual method of moments (MoM). 相似文献
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传输/反射法测量材料电磁参数的研究 总被引:26,自引:4,他引:22
分析了材料样品填充的矩形波导或同轴线等效网络的归一化通用矩阵,提出了一种求解材料电磁参数(εr,μr)的解析方法。分析表明,行性阻抗Zc与传播常数数γ均可直接由传/反射参数确定。同时应用特性阻抗与传播常数得到了磁性材料的电磁参数(εr,μr)。利用特性阻抗Zc、传播常数γ以及同时利用二者分别得到了三个确提高测量精度并确定测量误差;同时,可用于解决复介电常数测量的多值性问题与π模糊性问题。实际测试结果证明本文方法的有效的且有实用意义。 相似文献
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The transmission-reflection method is modified for measuring constitutive parameters of thin high-loss materials used as radar absorbers. The method uses a two-layer structure, consisting of a layer of thin flexible unknown material supported by a thicker rigid known material. The analysis and measurements focus on nonmagnetic samples of a high dielectric constant and loss factor and on the waveguide configuration in the X-band. A nonlinear least-squares optimization is used to obtain the complex permittivity from the measured scattering parameters. The uncertainty analysis presented facilitates selection of the support layer thickness. Simulations with the finite-difference time-domain method explore the effects of sample imperfections. Accuracy of a few percent can be achieved for a sample thickness of a fraction of a millimeter, provided that the thickness of the support dielectric is close to optimum and sample has only small surface imperfections. 相似文献
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Coves A. Gimeno B. Gil J. Andres M.V. Blas A.A.S. Boria V.E. 《Antennas and Propagation, IEEE Transactions on》2004,52(8):2091-2099
A novel vectorial modal method is presented for studying guidance and scattering of frequency-selective structures based on lossy all-dielectric multilayered waveguide gratings for both TE and TM polarizations. The wave equation for the transverse magnetic field is written in terms of a linear differential operator satisfying an eigenvalue equation. The definition of an auxiliary problem whose eigenvectors satisfy an orthogonality relationship allows for a matrix representation of the eigenvalue equation. Our proposed technique has been applied to the study of lossy all-dielectric periodic guiding media with periodicity in one dimension. This method yields the propagation constants and field distributions in such media. The reflection and transmission coefficients of a single layer under a plane-wave excitation can be obtained by imposing the boundary conditions. Study of the scattering parameters of the whole multilayered structure is accomplished by the cascade connection of components as characterized by their scattering parameters. Results obtained with this method for the propagation characteristics of a one-dimensional periodic dielectric medium are compared with those presented by other authors, and results for the scattering of several dielectric frequency-selective surfaces (DFSS) are compared with both theoretical and experimental results presented in the literature, finding a very good agreement. A symmetrical band-stop filter with a single waveguide grating is also demonstrated theoretically. 相似文献
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Humberto César Chaves Fernandez José de Ribamar Silva Oliveira Attílio José Giarola 《Journal of Infrared, Millimeter and Terahertz Waves》1991,12(5):505-519
The Transverse Transmission Line method is used for the characterization of bilateral and unilateral finlines on a semiconductor substrate and in conjunction with the modal method, for the calculation of the scattering parameters due to a step discontinuity on a unilateral finline with a lossless dielectric substrate. Numerical results of the effective dielectric constant, attenuation constant and characteristic impedance for the bilateral and unilateral finlines on semiconductor substrates, and results of scattering parameters of a step discontinuity for unilateral finline, are presented. 相似文献
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Strip dielectric wave guide antenna-for the measurement of dielectric constant of low-loss materials
Alok Kumar Rastogi A. K. Tiwari R. P. Shrivastava 《Journal of Infrared, Millimeter and Terahertz Waves》1993,14(7):1471-1483
The value of dielectric constant are the most important parameters in material science technology. In micro-wave and millimeter wave circuits using dielectric materials the values of this parameters should be known accurately. It is observed that the number of methods are reported in litrature, however these methods impose difficulties in experimentation and are not very accurate. In this paper a novel approach to the measurement of the dielectric constant of low loss materials at micro-wave and millimeter wave frequencies has been discussed. In this method by using antenna theory, a metallic strip dielectric guide is taken in to constideration and band reject phenomenon of dielectric antenna is used. Frequency response of an antenna in band reject mode is a function of the dimensional parameters, such as the metallic strip period, the profile of the metallic strip and the dielectric constant of the material used. Hence if one measure the frequency responce of the antenna in band reject mode, the dielectric constant of the material is determined provided all other parameters are known. This method gives a direct measure of dielectric constant and is quite accurate as computer techniques are used for evaluating the dielectric constant. This method verified experimentally also. 相似文献
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This paper presents a simple and effective wideband method for the determination of material properties, such as the complex index of refraction and the complex permittivity and permeability. The method is explicit (noniterative) and reference-plane invariant: it uses a certain combination of scattering parameters in conjunction with group-velocity data. This technique can be used to characterize both dielectric and magnetic materials. The proposed method is verified experimentally within a frequency range between 2-18 GHz on polytetrafluoroethylene and polyvinylchloride samples. A comprehensive error and stability analysis reveals that, similar to other methods based on transmission/reflection measurement, the uncertainties are larger at low frequencies and at the Fabry-Perot resonances. 相似文献