Dielectric
Mostrando 1-12 de 541 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 High-Gain Hemispherical Dielectric Lens Antenna Operating Simultaneously in Narrowband or Wideband for X-band Applications
Abstract A hemispherical dielectric lens antenna is proposed to provide beam-steering for communication networks operating in X-band. Two different printed antennas are simultaneously used to guarantee high performance and diversity of applications, one a wideband linear polarized antenna, and the other a narrowband circular polarized antenna. To ensure this
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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4. Bandpass Filter Using SIW Technology in Inductive Window Topology with Low-Cost Substrate FR-4
Abstract This paper features a step-by-step procedure for designing, simulate, and manufacture a bandpass filter using an inductive window topology within the substrate integrated waveguide (SIW) technology. We have chosen an operating frequency in the microwave range compatible with IoT circuits, employing a dielectric material, the FR-4, which is low cost
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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5. A Physical Study to Explain Response Differences between the BID and FID Detectors for PAHs and Pesticides
The dielectric barrier discharge ionization detector (BID) is one of the most modern detectors commercially available for gas chromatography (GC). Its technology based on the sample ionization through the energy released from the helium plasma generation process gives it the ability to act as a universal detector and a greater response to various types of co
Journal of the Brazilian Chemical Society. Publicado em: 2022
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6. 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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7. 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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8. YIG Matrix Based Multiband Magneto-Dielectric Cylindrical Resonator Antenna
Abstract A multiband magneto-dielectric resonator antenna with cylindrical geometry is proposed in this paper. The resonator is composed of yttrium iron garnet (YIG) with chemical composition Y3Fe2(FeO4)3. The final structure is built on a low-cost FR4 dielectric substrate. With only one resonator, the antenna is able to resonate in three distinct controlled
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
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9. 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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10. Proposed Technique of Analysis for Absorber/Transmitter Frequency Selective Surfaces
Abstract In this paper, we propose a simple technique to analyze absorber/transmitter frequency selective surfaces (FSS). The structure is formed by two FSS, one resistive and one conductive. Both FSS are printed on an FR4 dielectric substrate. The square loop and crossed dipole are the geometries considered in this paper. The technique combines two simple a
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
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11. 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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12. Study of structural, optical, and morphological characteristics of manganese titanate (MnTiO3) obtained by combustion reaction using microwave energy
Abstract MnTiO3 is a semiconductor that has relevant dielectric and optical properties. For the synthesis of manganese titanate (MnTiO3) powders, the combustion method via microwave and subsequent calcination at 500, 700, and 900 °C were used. The structural, morphological, and optical properties of the samples were investigated. X-ray diffraction analyzes
Cerâmica. Publicado em: 2021-03