Progress In Electromagnetics Research (Impact Factor: 5.3). 01/2007; 69:47-54. DOI: 10.2528/PIER06111204

ABSTRACT 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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    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. · 0.90 Impact Factor
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    ABSTRACT: A wide-band microwave characterization of nanocomposites based on commercial multiwalled carbon nanotubes (MWCNTs) and epoxy resin is presented. The sample preparation method is discussed in detail. Field emission scanning electron microscopy is used for morphological sample analysis of nanocomposites and MWCNTs. The complex permittivity is measured in a wide frequency band (3 to 18 GHz) using a commercial dielectric probe (Agilent 85070D) and a network analyzer (E8361A). A statistical analysis based on one-way analysis of variance (ANOVA) technique is performed. The aim of this statistical analysis is to investigate the influence of concentration of nanoparticles inside the polymer matrix on the complex permittivity. This can be significantly different in nanocomposites even if the samples have similar electrical properties.
    Progress In Electromagnetics Research Letters 01/2014; 44:63-69.
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    ABSTRACT: A simple and efficient solution for extracting the dielectric constant of liquids utilizing microstrip ring resonators simultaneously with rectangular waveguide (RWG) cavities is presented. Employing both techniques in a single structure is a confirmation procedure rather than comparing the obtained results with any other standard method. The proposed structure is intended to be mechanically suited for holding liquid samples without enclosing any air gaps which enhances the measurement sensitivity. Since the structure is being totally enclosed, the loaded quality factor will be consequently increased due to the absence of radiation losses. The waveguide cavity acts as metallic enclosure for the ring circuit in order to maintain the design procedures as well.
    Proceedings of PIERS Conference 2008, Cambridge-USA; 07/2008


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May 22, 2014