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- 2018
- arbitrary coupling coefficients
- Dielectric resonator
- filtering
- coupler
- filtering balun
- dual-band
- dual-mode dielectric resonator (DR)
- Electronic Science and Technology
- Nantong University
- Sun Yat-Sen University
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Dielectric Properties of NaCu <sub/>3</sub> Ti <sub/>3</sub> Nb <sub/>1–x</sub> Sb <sub/>x</sub> O <sub/>12</sub> Ceramics
摘要： In order to investigate the influence of Sb doping on the dielectric properties of NaCu3Ti3NbO12 ceramics, a series of NaCu3Ti3Nb1–xSbxO12 ceramics were prepared by conventional solid-state reaction technique. Their crystalline structure, microstructure, dielectric properties and complex impedance were systematically investigated. All these ceramics show giant permittivity phenomenon, and their low-frequency dielectric loss decrease significantly but permittivity remains large with increased Sb doping. Impedance spectroscopic analysis reveals that NaCu3Ti3Nb1–xSbxO12 ceramics are composed of insulating grain boundaries and semiconducting grains, and their resistance of grain boundary increases with increased Sb doping. According to internal barrier layer capacitance effect, the decrease of low-frequency dielectric loss in NaCu3Ti3Nb1–xSbxO12 ceramics with increased Sb doping should be caused by the increase of grain boundary resistance.
关键词： Internal barrier layer capacitance effect,NaCu3Ti3Nb1–xSbxO12 ceramics,Grain boundary resistance,Low-frequency dielectric loss
更新于2025-09-04 15:30:14
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ELECTROMAGNETIC SCATTERING BY APPROXIMATELY CLOAKED DIELECTRIC CYLINDER
摘要： In cloaking, a body is hidden from detection by surrounding it by a coating consisting of an unusual anisotropic nonhomogeneous material. The permittivity and permeability of such a cloak are determined by the coordinate transformation of compressing a hidden 2D or cylindrical body into a line. Some components of the electrical parameters of the cloaking material (ε, μ) are required to have in?nite or zero value at the boundary of the hidden object. In order to eliminate the zero or in?nite values of the electrical parameters, approximate cloaking can be used by transforming the cylindrical body virtually into a small cylinder rather than a line, but this produces some scattering. The solution is obtained by rigorously solving Maxwell equations using angular harmonics expansion. In this work, the scattering pattern, and the backscattering cross section against the frequency for cloaked dielectric cylinder are studied for both transverse magnetic (TMz) and transverse electric (TEz) polarizations of the incident plane wave for di?erent transformed body radii.
关键词： dielectric cylinder,TEz,electromagnetic cloaking,approximate cloaking,TMz,scattering
更新于2025-09-04 15:30:14
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Strain-Mediated Substrate Effect on the Dielectric and Ferroelectric Response of Potassium Sodium Niobate Thin Films
摘要： If piezoelectric thin films sensors based on K0.5Na0.5NbO3 (KNN) are to achieve commercialization, it is critical to optimize the film performance using low-cost scalable processing and substrates. Here, sol–gel derived KNN thin films are deposited using a solution with 5% of potassium excess on Pt/TiO2/SiO2/Si and Pt/SrTiO3 substrates, and rapid thermal annealed at 750 ?C for 5 min. Despite an identical film morphology and thickness of ~335 nm, an in-plane stress/strain state is found to be tensile for KNN films on Pt/TiO2/SiO2/Si, and compressive for those on Pt/SrTiO3 substrates, being related to thermal expansion mismatch between the substrate and the film. Correspondingly, KNN films under in-plane compressive stress possess superior dielectric permittivity and polarization in the parallel-plate-capacitor geometry.
关键词： stress/strain,ferroelectric hysteresis,dielectric properties,KNN thin films,sol–gel,thermal expansion
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Chengdu (2018.3.26-2018.3.28)] 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Polarization Reconfigurbale Antenna with Liquid Metal
摘要： In this paper, we present a polarization reconfigurable liquid dielectric resonator antenna (DRA) incorporating liquid metal. For the liquid dielectric solution, we use ethyl acetate and for the liquid metal solution, an alloy called Galinstan was used. Before introduction of the liquid metal electric field within the DRA was orientated along the Y-axis. Then by injecting the liquid metal into the liquid dielectric, the electric field rotated 45 degrees. Consequently, polarization reconfiguration was achieved. All of the results presented in this paper were obtained through computer simulation in HFSS.
关键词： liquid metal,Liquid dielectric resonator antenna,polarization reconfigurable antenna
更新于2025-09-04 15:30:14
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[Ceramic Transactions Series] Proceedings of the 12th Pacific Rim Conference on Ceramic and Glass Technology (Ceramic Transactions) || Dielectric Properties of Confined Ionic Liquids
摘要： Ionic liquids, as solvent free electrolytes, are promising materials improving the energy density of future storage devices. Two key requirements for such an application are a broad electrochemical window and a high ionic mobility of ionic liquids. A thorough measurement of the dielectric properties in a broad temperature and frequency regime allows analyzing the latter one in detail. Ionic mobility is influenced by intrinsic relaxations. These relaxations are influenced by correlation between the molecules. Confining the molecules allows to access this correlation length and to address the fundamental questions regarding supercooled liquids. We demonstrate this by confining the ionic liquid 1-butyl-3-methyl-imidazolium chloride in a metal-organic-framework, namely MFU-4. The preliminary results of an enhanced rotational motion compared to the bulk ionic liquid point towards a temperature, where the correlation length corresponds to the pore diameter of the confining host.
关键词： Ionic liquids,confinement,metal-organic-framework,BMIM-Cl,MFU-4,dielectric properties
更新于2025-09-04 15:30:14
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Optical, dielectric properties and thermal analysis on sodium sulfanilate dihydrate nonlinear optical single crystal
摘要： Nonlinear optical sodium sulfanilate dihydrate (SSD) single crystal was grown by slow evaporation solution method at ambient temperature. Unit cell parameters were elucidated with the study of single crystal X-ray diffraction. Fourier transform infrared spectroscopic analyses were performed to indentify a variety of functional groups present in the grown SSD crystal. The level of optical transmittance of the grown SSD crystal was investigated by UV–Vis–NIR spectral analysis. The lower cut off wavelength of the grown crystal was observed at 243 nm and the band gap energy is found to be 5.23 eV. The spectral study of photoluminescence was carried out for the grown crystal which shows a sharp emission peak at 485 nm resulting blue–green emission that is suitable for the optical communication applications. Mechanical strength was measured by utilizing Vickers microhardness test and the value of n is found to be 2.25 asserting that the crystal belongs to soft material category. The dielectric properties were studied as a function of frequency at various temperatures and also the grown SSD crystal has been correlated with electro-optic properties. Thermogravimetric analysis was undertaken by a thermal analyzer with the temperature starting from 30 to 800 °C and TGA/DTA results show that the crystal has good thermal stability and useful for laser applications. Etching analysis also was performed for the grown SSD single crystal proving that it has good crystalline nature with fewer defects.
关键词： Thermal analysis,Sodium sulfanilate dihydrate,Nonlinear optical materials,Dielectric properties,Optical properties,Crystal growth
更新于2025-09-04 15:30:14
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Recent development on modification of synthesized barium titanate (BaTiO3) and polymer/BaTiO3 dielectric composites
摘要： In order to fabricate barium titanate (BaTiO3) particles with high purity, small particle size and narrow distribution of particle size, the synthesis methods and doping elements should be properly selected. Compared to polar polymers, non-polar polymers have advantages on the fabrication of miniaturized and lightweight electronic devices, due to excellent process-ability and little endogenous heat generated in the electric field. To avoid the aggregation of BaTiO3 particles in polymer matrix, several nanometer thick organic coating on the BaTiO3 surface is needed. What’s more, the alignment of BaTiO3 and hybrid use of fillers can further improve the dielectric properties of polymer/BaTiO3 composites.
关键词： Barium titanate,Synthesis methods,Dielectric properties,Surface modification,Polymer composites
更新于2025-09-04 15:30:14
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Synthesis and characterization of photo-crosslinkable coumarin-containing polymer dielectric for organic transistors
摘要： Herein, a photo-crosslinkable coumarin-containing polymer, poly(7-(4-vinyl-benzyloxyl)-4-methylcoumarin) or PVBMC, was prepared, and its physicochemical and electrical properties as a gate dielectric in organic electronic devices, such as organic thin-film transistor (OTFT) and inverter, was evaluated. The crosslinking of PVBMC by exposure to UV light (365 nm) over time was characterized using Fourier-transform IR and UV-visible spectroscopy. The measured capacitance of the cross-linked PVBMC thin film in a metal-insulator-metal-type capacitor was as high as 36.4 pF/mm2. Pentacene-based OTFT and load-type inverter with the cross-linked PVBMC gate dielectric were prepared, and their electrical responses were evaluated under ambient conditions. The OTFT showed dominant hole charge carrier transport behavior with a field-effect mobility of 1.52 · 10-1 cm2/Vs and negligible hysteresis. The load-type inverter based on the OTFT exhibited moderate static and dynamic switching responses to the applied electrical pulse. These results suggest the potential application of photo-crosslinked PVBMC as a gate dielectric in the fabrication of high-performance OTFT-based devices.
关键词： Gate dielectric,Polymer film,Organic thin-film transistor,Photo-crosslinking
更新于2025-09-04 15:30:14
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Model of GaSb-InAs p-i-n Gate All Around (GAA) BioTunnel FET (BTFET)
摘要： The paper investigates the role of hetero-Junction (HJ) p-i-n Gate All Around GAA Tunnel FET architecture for biosensing applications. The device offers better sensitivity and has been modeled in terms of various parameters such as surface potential, threshold voltage and drain current. Analytical modeling scheme relates to the exact resultant solution of two-dimensional Poisson equation. The shift in the threshold voltage has been considered as the sensing parameter to detect the sensitivity when the biomolecules are immobilized in the cavity region.
关键词： Gate all around tunnel FET (GAA-TFET),Model,Bio-Sensor,Hetero Junction (HJ),Dielectric Modulation
更新于2025-09-04 15:30:14
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Characterization of dielectric properties and conductivity in encapsulation materials with high insulating filler contents
摘要： The properties of different molding-compound materials with high filler contents have been investigated in order to assess their electrical properties. The experimental part of the present work has been focused on dielectric spectroscopy and steady-state conduction measurements. The results have been used to investigate the electrical properties of the materials at different frequencies, temperatures and electric fields. Differences in the relaxation kinetics with increasing filler content have been found, which can be ascribed to the larger interface regions between the filler particles. In addition, the extracted conductivities show a hopping transport and different activation energies on the temperature range from 20 oC to 190 oC.
关键词： dielectric polarization,epoxy resins,spectroscopy
更新于2025-09-04 15:30:14