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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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Thermal analysis and crystal growth of doped Nb2O5
摘要： The systems Nb2O5–Ta2O5 and Nb2O5–V2O5 were investigated using thermal analysis, X-ray powder diffraction and thermodynamic simulations. Solid solution formation is possible for both systems; furthermore, both contain one intermediate compound, VNb9O25 or Ta2Nb4O15, respectively. Phase relationships for pure niobium(V)-oxide and tantalum(V)-oxide were studied under ambient pressure. It was found that both compounds can occur in two stable solid modifications. For niobium(V)-oxide this are the monoclinic high-temperature modification (H-Nb2O5) and an orthorhombic low-temperature modification (T-Nb2O5) and for tantalum(V)-oxide a tetragonal high-temperature form (α-Ta2O5) and an orthorhombic low-temperature form (β-Ta2O5). Based on these results, crystal growth experiments with various compositions from both systems were carried out using the optical floating zone (OZF) technique.
关键词： B2. dielectric materials,A2. growth from melt,A1. doping,A1. phase diagrams,B1. niobates
更新于2025-09-23 15:23:52
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Nonlinear Diffraction in Asymmetric Dielectric Metasurfaces
摘要： Metasurfaces provide new and promising mechanisms to control and manipulate light at the nanoscale. While most metasurfaces are designed to operate in the linear regime, it was recently shown that such metasurfaces may also generate nonlinear signal, by manipulating the higher order susceptibility terms. As such, metasurfaces can generate additional harmonics, without the need for light propagation, as typically occur in nonlinear crystals. While such demonstrations typically rely on the nonlinear properties of metals, we hereby report the design, fabrication and experimental characterization of a resonant dielectric metasurface made of amorphous silicon to create and manipulate second harmonic light and control its diffraction patterns. As shown in the paper, the second harmonic generation of light follows selection rules which rely on the asymmetry of the meta-atom. Given the fact that silicon crystals are centrosymmetric, the generation of second harmonic signal in amorphous silicon is intriguing. In fact, second harmonic signal is generated mostly from the surface of the meta atom. It is the use of nanostructures that increases the surface to volume ratio and enables second harmonic generation. Additionally, the meta atom is designed to exploit its spectral resonances in the principal and the second harmonic frequencies for providing electromagnetic field enhancement which assist in boosting up the generation of second harmonic signal.
关键词： Metasurfaces,Nonlinear optics,Dielectric metasurfaces,Phase gradient metasurfaces
更新于2025-09-23 15:23:52
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A Wideband Polarization-Reconfigurable Water Dielectric Resonator Antenna
摘要： A water dielectric resonator antenna (DRA) with reconfiguration and broadband characteristics is presented. By injecting pure water into various cavities of the plexiglass holder, the antenna can be switched among left hand circular polarization (LHCP), right hand circular polarization (RHCP) and linear polarization (LP) in almost the same operating frequency range. With the high relative permittivity, water acts as a dielectric resonator as well as an interface similar to electric wall to form a broad axial ratio bandwidth. Thus a broad usable bandwidth is measured to be over 22%, and the measured radiation efficiency and realized gain centralize in 60%-70% and 3-4 dBi respectively.
关键词： dielectric resonator antenna,water antenna,broad bandwidth,dielectric dense patch antenna,reconfigurability
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Auckland (2018.8.5-2018.8.8)] 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Design of Band-notched UWB Rectangular Dielectric Resonator Antenna
摘要： A rectangular dielectric resonator antenna fed by microstrip line at non-central symmetric position with partial ground plane is presented. The proposed dielectric resonator with given dimensions is easy to excite multiple modes and generate the broadband of 7.09GHz, ranging from 3.89 to 10.98GHz. Due to the introduction of parasitic metal ring, band-notched property can be achieved. When the total length comes to the half a guide wavelength, the notched band at corresponding frequency is generated. Simulations confirm the validation of the design principle. The compact size of the band-notched DRA is 25mm×28mm with 4.037mm thickness.
关键词： rectangular dielectric resonator,UWB,dielectric resonator antenna,band-notched
更新于2025-09-23 15:22:29
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Enhanced performance of porous silicone-based dielectric elastomeric composites by low filler content of Ag@SiO <sub/>2</sub> Core-Shell nanoparticles
摘要： In the present work, micropores and a low filler content of Ag@SiO2 nanoparticles (NPs) are synchronously introduced into polydimethylsiloxane (PDMS) film to obtain porous dielectric elastomeric composites. The morphology and dielectric and mechanical properties of the composites are investigated. The resulting composites possess high dielectric permittivity, low dielectric loss and low Young’s modulus, which is beneficial to the requirements of a dielectric elastomer actuator. This study provides an effective method to prepare high-performance PDMS-based dielectric porous dielectric elastomeric composites filled with low filler contents of Ag@SiO2 NPs.
关键词： core-shell particles,dielectric loss,Young’s modulus,dielectric permittivity,elastomer,Porous materials
更新于2025-09-23 15:22:29
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Novel Three-Dimensional SiC/Melamine-Derived Carbon Foam-Reinforced SiO <sub/>2</sub> Aerogel Composite with Low Dielectric Loss and High Impedance Matching Ratio
摘要： Novel three-dimensional SiC/melamine-derived carbon foam composite filled by silica aerogel (SiC/MDCF?Aerogel) was first fabricated by the pyrolysis process of commercial melamine foam, chemical vapor deposition of ultrathin SiC films, and the sol?gel method of silica aerogel. The results indicated that the SiC/MDCF?Aerogel composite consisted of the SiC three-dimensional open-celled network structure and the pregnant silica aerogel in the pores. Tiny cracks on the interface of skeletons and clumps were induced during the aging process, which was drastically beneficial to the microwave-absorbing properties. A minimum reflection loss could be obtained as low as ?18.41 dB at the measured frequency of 16.92 GHz when the thickness of the absorber was 3.65 mm, and the reflection loss could drop below ?10 dB when the selected frequencies ranged from 15.80 to 17.52 GHz, along with the thickness ranging from 2.75 to 5.0 mm, which possessed a relatively better microwave absorption performance especially at a higher frequency. Furthermore, the absorption mechanism was also investigated in detail to discuss the influence of the dielectric loss and the impedance matching ratio on the microwave-absorbing performance of SiC/MDCF?Aerogel, which provided certain scientific directions for evaluating the absorbing materials.
关键词： Minimum reflection loss,Tiny cracks,Microwave-absorbing properties,Impedance matching ratio,Dielectric loss,SiC/MDCF?Aerogel
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Conference on RFID Technology & Application (RFID-TA) - Macau, Macao (2018.9.26-2018.9.28)] 2018 IEEE International Conference on RFID Technology & Application (RFID-TA) - Polarization Reconfigurable Antenna with Beam Steering Performance
摘要： This paper proposed a novel method reconfiguring the polarization of the dielectric resonator antenna (DRA) with beam steering performance. During the process of liquid alteration between the two zones of the 3-D printed container, the proposed antenna performed with beam steering performance. What's more, the polarization was switched with the beam steering process. The proposed design is suitable for the application as a RFID reader.
关键词： dielectric resonator antenna,Radio frequency identification (RFID),polarization reconfigurable,beam steering
更新于2025-09-23 15:22:29
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Solution-processed amorphous gallium-tin oxide thin film for low-voltage, high-performance transistors; 溶液法制备低电压及高性能非晶GaSnO薄膜晶体管;
摘要： Gallium-tin oxide (GTO) semiconductor thin films were prepared by spin-coating with 2-methoxyethanol as the solvent. Their crystal structures, optical transparency, chemical states and surface morphologies, along with the electrical properties, were dependent on Ga contents and annealing temperatures. The optimized GTO channel layer was applied in the high-k Al2O3 thin film transistor (TFT) with a low operation voltage of 2 V, a maximum field-effect mobility of 69 cm2 V?1 s?1, a subthreshold swing (SS) of 76 mV dec?1, a threshold voltage of 0.67 V and an on-off current ratio of 1.8×107. The solution-processed amorphous-GTO-TFTs would promote the development of low-consumption, low-cost and high performance In-free TFT devices.
关键词： GTO semiconductor films,thin-film transistor,Al2O3 dielectric,stability
更新于2025-09-23 15:22:29
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Structural, optical, and dielectric properties of Cu, Ni-doped Zn ferrites
摘要： Ferrite nanocomposites with the composition Cu0.5Zn0.5Fe2O4 and Ni0.5Zn0.5Fe2O4 were prepared by co-precipitation method. The effect of dopant to spinel ferrite ZnFe2O4 on the structural, morphological, optical, and dielectric properties of the as-prepared Cu-Zn and Ni-Zn ferrites were investigated. The structural, elemental, and optical properties conducted by using X-ray diffraction (XRD) technique with Cu/Kα radiation, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), Raman spectroscopy, and UV–Vis reflectance spectroscopy. For the electrical properties of the Cu-Zn and Ni-Zn ferrites, a real part of the dielectric constant and AC conductivity have been investigated with a frequency range of 20 Hz to 10 MHz at different temperature for each sample. The substitutions of Cu and Ni into the ZnFe2O4 nanocomposites crystal size calculated 20.36 nm for Cu-Zn ferrite and 10.95 nm for Ni-Zn ferrite. Also, the energy band gap of Cu-Zn ferrite is 2.6 eV and Ni-Zn ferrite is 2.83 eV. These results show that the energy band gap is increased when the crystal size is reduced by the substitution of Ni into the Zn ferrite. The dielectric constant and AC conductivity of Cu-Zn ferrite is bigger than the Ni-Zn ferrite at low frequencies. This situation is related to the structural parameters. Also, the AC conductivity increases with an increasing frequency and temperature.
关键词： AC conductivity,Co-precipitation,Cu-Zn ferrites,Dielectric constant,Ni-Zn ferrites
更新于2025-09-23 15:22:29
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Design of a Circularly Polarized Dielectric Resonator Antenna with Wide Bandwidth and Low Axial Ratio Values
摘要： A circularly polarized (CP) dielectric resonator antenna (DRA) with wide bandwidth and low axial ratio (AR) values is presented in this communication. The antenna consists of a stacked DRA, and it is fed by a substrate integrated waveguide (SIW) coupling slot from the bottom. The stacked DRA structure, with high permittivity dielectric strips layered on low permittivity substrate, is adopted for bandwidth and gain benefits. Here, a pair of dielectric strips rather than a single one is placed above the coupling slot with 45° inclination for generating good CP radiation, and it is elaborately designed to provide three closely coupled CP modes, constituting a wide operating bandwidth. To facilitate the application in antenna array, a cavity-backed antenna design along with a 2×2 sub-array are further presented. To verify the design, a sub-array prototype is developed and tested at Ku-band for satellite applications, showing an impedance bandwidth of 25.1%, a wide 1-dB AR bandwidth of 15.6%, and a peak gain of 15.1dBi.
关键词： substrate integrated waveguide,low axial ratio values,wide bandwidth,Dielectric resonator antenna
更新于2025-09-23 15:22:29