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Dielectric loss
About: Dielectric loss is a research topic. Over the lifetime, 20296 publications have been published within this topic receiving 349254 citations.
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27 Jan 2003
TL;DR: In this article, a coated susceptor of electromagnetic energy for chemical processing made of a matrix material that surrounds a non-matrix material that is made from a material different from the matrix material, is presented.
Abstract: A coated susceptor of electromagnetic energy for chemical processing made of a matrix material that surrounds a non-matrix material that is made from a material that is different from the matrix material, in which the matrix material is constructed of material having lower dielectric losses compared to the non-matrix material, the non-matrix material initially absorbs electromagnetic energy applied to the electromagnetic susceptor to a greater extent than the matrix material, the non-matrix material produces subsequent heat in the matrix material, and the surface of the susceptor is coated with a material that interacts with applied electromagnetic energy of at least one frequency and initially absorbs electromagnetic energy and produces heat.
146 citations
TL;DR: In this article, six sillenite compounds were synthesized to obtain ∼97% dense ceramics, and an analysis of their microwave dielectric properties, performed at ∼5.5 GHz, revealed a permittivity of ∼40 for all six compounds.
Abstract: Six sillenite compounds Bi12MO20-δ (M = Si, Ge, Ti, Pb, Mn, B1/2P1/2) were synthesized, and the resulting single-phase powders were then sintered to obtain ∼97% dense ceramics. An analysis of their microwave dielectric properties, performed at ∼5.5 GHz, revealed a permittivity of ∼40 for all six compounds. The temperature coefficient of resonant frequency was the lowest for the Pb analogue (−84 ppm/K) and was found to increase with increasing ionic radius of the B-site ion to a value of −20 ppm/K for the Bi12SiO20 and Bi12(B1/2P1/2)O20 compounds. The Q×f value is a maximum for Bi12SiO20 and Bi12GeO20 with 8100 and 7800 GHz, respectively. The dielectric properties of the sillenites have been correlated with the structure of the oxygen network of the sillenite crystal lattice. As a result of its low sintering temperature (850°C), chemical compatibility with silver, low dielectric losses, and temperature-stable permittivity, the Bi12SiO20 compound is a suitable material for applications in low-temperature cofiring ceramic (LTCC) technology.
145 citations
TL;DR: In this article, temperature-induced anomalies in the dielectric, piezoelectric and elastic coefficients and Raman spectroscopy of ceramic BCZT were reported.
Abstract: The solid solution 0.5Ba(Ti0.8Zr0.2)O3-0.5(Ba0.7Ca0.3)TiO3 (BCZT) is a promising lead-free piezoelectric material with exceptionally high piezoelectric coefficients. The strong response is related to structural instabilities close to ambient temperature. We report here on temperature-induced anomalies in the dielectric, piezoelectric, and elastic coefficients and Raman spectroscopy of ceramic BCZT. The data indicate ferroelectric-ferroelectric structural phase transitions in this material in addition to those previously reported. An anomaly is also observed above the Curie temperature TC and is associated with the loss of polar structure that persists thirty degrees above TC.
145 citations
TL;DR: In this paper, the dielectric properties of the diglycidyl ether of Bisphenol A with 4,4‘-diaminodicyclohexylmethane in the temperature range 290−353 K were studied.
Abstract: Dielectric relaxation spectroscopy (DRS) and differential scanning calorimetry (DSC) have been used simultaneously as a means of following the isothermal cure of the diglycidyl ether of Bisphenol A with 4,4‘-diaminodicyclohexylmethane in the temperature range 290−353 K. The dielectric permittivity and dielectric loss of the thermosetting mixture have been measured as a function of reaction time over the frequency range 101.2−105 Hz. The evolution of the dielectric properties was studied as the curing temperature was lowered to values close to the solidification of a sample. The kinetics of the cure have also been determined, using calorimetry, for four reaction temperatures over the whole range of conversion up to the point where the system vitrifies and the reaction becomes diffusion-controlled. Correlations between the changes in molecular dynamics and the chemical kinetics occurring during the thermosetting process have been made in some detail, and a theoretical working model has been developed that a...
145 citations
TL;DR: In this paper, Fe3O4@C/reduced graphene oxide (rGO) nanocomposites with layered structure were fabricated by a feasible solvothermal method.
Abstract: Reasonable nanostructure design and composition are conducive to the electromagnetic wave (EM) absorption behavior of absorbers. Herein, Fe3O4@C/reduced graphene oxide (rGO) nanocomposites with layered structure were fabricated by a feasible solvothermal method. By adjusting the amount of graphene oxide (GO), different dielectric characteristics and impedance matching conditions of Fe3O4@C/rGO nanocomposites could be obtained. Moreover, with amorphous carbon as the matching layer, Fe3O4 and rGO provide strong magnetic loss and dielectric loss, respectively. The results exhibit that Fe3O4@C/rGO nanocomposites own salient EM absorption properties under the combined action of various components and three-level layered structure. In addition, the Fe3O4@C/rGO-20 nanocomposites (the addition of GO is 20 mg) are endowed with the best EM absorption performance, which demonstrates a minimum reflection loss (RLmin) value of −59.23 dB at 6.24 GHz with a sample thickness of 3.57 mm and effective absorption bandwidth (EAB) is 6.72 GHz. Moreover, the widest EAB is 8.24 GHz at a thinner thickness of 2.6 mm with the RL value of −25.80 dB at 14 GHz. This work could be a reference for lightweight, broadband, strong absorption composite absorber.
145 citations