Dielectric Loss
Mostrando 1-12 de 75 artigos, teses e dissertações.
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1. Analysis of dielectric and electrical transport properties of NdFeAsO ceramic
Abstract The iron-based ceramic NdFeAsO was synthesized by the solid-state reaction method. The tetragonal crystal structure was confirmed at room temperature through the X-ray diffraction technique. The dielectric characteristics i.e. dielectric constant (εr) and loss tangent (tanδ) of the sample were studied at a wide range of temperature and frequencies
Cerâmica. Publicado em: 2022
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2. Investigate the Effect of Dielectric Properties on Microwave Absorption of Pyramidal Microwave Absorber
Abstract This paper presents an analysis of the impact of various dielectric properties material’s effects on broadband pyramidal microwave absorbers (PMA). The Computer Simulation Technology (CST) studio software simulates and analyzes the PMA over 0.7 GHz to 30 GHz frequency range. To achieve the best reflectivity performance of the PMA, different types
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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3. A Design of a Compact Microwave Diplexer in Microstrip Technology Based on Bandpass Filters Using Stepped Impedance Resonator
Abstract This paper describes the design of a compact microstrip microwave diplexer based on bandpass filters and a stepped impedance resonator for 4G applications. The diplexer is composed of two band-pass filters (BPF) that operate at 1.8 and 2.5 GHz. Both bandpass filters for the receiver at 1.705-1.895 GHZ and the transmitter at 2.41-2.6 GHZ have a -3dB
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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4. Ferrimagnetic to paramagnetic transition and dielectric relaxation in Ni1-xZnxFe2O4 ferrites
Abstract The spinel ferrite system Ni1-xZnxFe2O4 (x=0-0.7, Δx=0.1) was prepared by wet chemical co-precipitation method using sulfates of respective metal ions. The electrical resistivity and dielectric properties of the prepared samples have been studied as a function of temperature, frequency, and Zn content (x). The DC resistivity (ϱ) was measured in th
Cerâmica. Publicado em: 2021-06
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5. Wavelength-Selective Near Unity Absorber Based on Fabry-Pérot Nanoresonators
Abstract We proposed and analyzed a planar narrow-band absorber based on a bi-layer metal/dielectric structure. The planar absorber uses the Fabry-Pérot resonance and the inherent loss of the metals, for maximum light absorption in the range of the electromagnetic spectrum visible to the near infrared. The absorption resonance peak can be shifted to other r
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
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6. Cold sintering and electric characterization of ZnO-BaTiO3 composites
Abstract The sintering is an essential step in the processing of ceramics materials. A number of researchers have reported new techniques for sintering. However, in general, the process still demands high temperatures. This paper reports the results of the cold sintering of ZnO-BaTiO3 composites. The microstructural, structural, and electric properties of th
Cerâmica. Publicado em: 2021-03
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7. Ground-Penetrating Radar Antenna Design for Homogeneous and Low-Loss Dielectric Multilayer Media
Abstract Non-destructive evaluation of multilayer media represents an electromagnetic inverse problem, usually solved with analysis techniques in the time and frequency domains. The time- domain analysis technique depends directly on the accurate detection of reflected peaks measured by ground-penetrating radar (GPR), which limits this technique when the ref
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-06
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8. Project and Analysis of Quasi-Periodic PBG for Microstrip Antenna
Abstract In this work the influence of quasi-periodic distributions of air holes with 6, 12 and 6-fold modified symmetries, applied to the substrate of a rectangular microstrip patch antenna are analyzed. To validate the study, parameters such as S11 parameter, bandwidth, total gain, radiation pattern and electric field were investigated through computationa
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-06
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9. Characterization of the Dielectric Properties of the Tommy Atkins Mango
Abstract This paper presents the characterization of dielectric properties (dielectric permittivity and dielectric loss factor) of Tommy Atkins mango (Mangifera indica L), a fruit produced in several regions of Brazil, of great economic importance. The fruits were characterized according to their maturation index, by probe method, and identified by the yello
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-03
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10. Dielectric Behavior of α-Ag2WO4 and its Huge Dielectric Loss Tangent
The microwave-assisted hydrothermal method was used to obtain α-Ag2WO4. Rietveld refinement confirmed that α-Ag2WO4 is stable in the orthorhombic phase, without secondary phase. However, field-effect scanning electron microscope analysis showed that α-Ag2WO4 nanorods surfaces contain silver nanoparticles, confirmed by the X-ray photoelectron spectroscopy
Mat. Res.. Publicado em: 02/09/2019
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11. Dielectric and electrical properties of a mullite/glass composite from a kaolinite clay/mica-rich kaolin waste mixture
Resumo Um compósito mulita/fase vítrea foi preparado por sinterização reativa de uma mistura argila caulinítica/resíduo de caulim rico em mica com 25% em massa de resíduo. A composição de fase, microestrutura, propriedades dielétricas e elétricas do compósito sinterizado a 1400 °C foram avaliadas por difração de raios X, microscopia eletrônic
Cerâmica. Publicado em: 2019-01
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12. Transport Properties of Polycrystalline Mixed Copper-Zinc Ferrites
Polycrystalline mixed Cu-Zn spinel ferrites with general formula Cu1-xZnxFe2O4 (x = 0.0, 0.1, 0.3, 0.5 and 0.7) have been prepared by solid-state reaction method. The effect of Zn2+ ions on transport properties such as DC and AC resistivity, dielectric constant and dielectric loss tangent has been presented in this paper. The resistivity increases with Zn co
Mat. Res.. Publicado em: 19/04/2018