Measurement of dielectric constant and loss factor of the dielectric material at microwave frequencies

Progress In Electromagnetics Research (Impact Factor: 1.23). 01/2007; 69:47-54. DOI: 10.2528/PIER06111204


A new technique to evaluate the dielectric constant and loss factor of a homogeneous dielectric material using rectangular shaped perturb cavity has been developed. The values of S-parameters are measured experimentally by placing the sample in the center of the cavity resonator. Sample under test is fabricated in the form of a cylinder. The real and imaginary part of the permittivity can be then calculated from the shift in the resonance frequency and Q-factor. The results of a Teflon sample are also tabulated.

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    • "Over the years, numerous methods have been used to calculate the í µí±‡/í µí±… coefficient of samples at microwave frequency . In the recent, Dudek et al. (1992) and Kumar et al. (2007), the vector network analyzer (VNA) has been used successfully to obtain the í µí±† parameters of samples in the microwave wave range [1] [2]. A new approach is presented that relies upon 3D electromagnetic simulation results to characterize and calculate the í µí±‡/í µí±… coefficient using FEM. "
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    ABSTRACT: PTFE samples were prepared with different thicknesses. Their electric field intensity and distribution of the PTFE samples placed inside a rectangular waveguide were simulated using finite element method. The calculation of transmission/reflection coefficients for all samples thickness was achieved via FEM. Amongst other observable features, result from calculation using FEM showed that the attenuation for the 15 mm PTFE sample is −3.32 dB; the 30 mm thick PTFE sample has an attenuation of 0.64 dB, while the 50 mm thick PTFE sample has an attenuation of 1.97 dB. It then suffices to say that, as the thickness of the PTFE sample increases, the attenuation of the samples at the corresponding thicknesses increases.
    Advances in Materials Science and Engineering 01/2014; 2014. DOI:10.1155/2014/965912 · 0.74 Impact Factor
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    • "It must be stressed that the rectangular cavity has been effectively employed as a device for permittivity measurements [19], [20] since, despite its narrow band, it allows Fig. 1. Sketch of the rectangular waveguide cavity. "
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    ABSTRACT: This paper presents 1 the design, fabrication, and characterization of a microwave resonator as a tool for concentration measurements of liquid compounds. The sensing device is a rectangular waveguide cavity tuned at 1.91 GHz, which exploits the fundamental TE101 mode in a transmission-type configuration. The coupling structure is optimized by means of a finite element code so as to achieve a high Q-factor. According to the type of substance inside the mixture, its concentration is conveniently related to changes of the S21 scattering parameter (transmission coefficient) in terms of: 1) resonance frequency; 2) 3-dB bandwidth; and 3) amplitude at the resonance frequency. Experimental tests on liquid solutions in controlled conditions are presented to evaluate the performance of the device.
    IEEE Sensors Journal 05/2013; 13(5):1857-1864. DOI:10.1109/JSEN.2013.2244035 · 1.76 Impact Factor
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    • "The reliability of the high voltage equipment used in electric power systems such as power cables, power transformers, capacitors etc. significantly depends on material insulation [1] [2]. Dielectric losses which occur in high voltage equipment are an important indicator of the insulation [1] [2] [3] [4]. Therefore, tan delta and capacitance values of the insulation material are important parameters for determining the dielectric performance of high voltage cables [5]. "
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    ABSTRACT: Insulation quality issue has had a significant place in high voltage systems for long years. Especially for high voltage cables, which is one of the most crucial elements in power systems, the measurements of dissipation factor or tan delta has a great importance on the insulation life time. Besides, when the power system parameters such as frequency and voltage level are not steady, tan delta measurement values will also be changed. Therefore, tan delta and dielectric loss measurement should be realized in case of unsteady power system conditions to get more exact results. In this study, tan delta measurement of a 20,1/34,5 kV, single core high voltage cable is carried out. By changing the frequency and voltage level, dissipation factor, capacitance (Cs), insulation resistance (Rs) and dielectric losses (Pk) measurement values are obtained.
    EUROCON, 2013 IEEE; 01/2013
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