- 标题
- 摘要
- 关键词
- 实验方案
- 产品
过滤筛选
- 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
-
Enhanced gate stack stability in GaN transistors with gate dielectric of bilayer SiN <sub/>x</sub> by low pressure chemical vapor deposition
摘要： We report enhanced gate stack stability in GaN metal insulator semiconductor high electron mobility transistors (MISHEMTs) by using a bilayer SiNx as the gate dielectric. To obtain the bilayer gate dielectric scheme, a thin Si-rich SiNx interlayer was deposited before a high-resistivity SiNx layer by low pressure chemical vapor deposition. The Si-rich SiNx can effectively suppress the trapping phenomenon at the interface of the dielectric/AlGaN barrier. The upper high-resistivity SiNx layer can greatly block the gate leakage current to enable a large gate swing. Compared with the MISHEMTs using a single Si-rich or high-resistivity SiNx layer, the MISHEMTs with a bilayer gate dielectric take the advantages of both, realizing a gate stack with a stable threshold voltage and low leakage current. These results thus present great potential for developing high-performance GaN MISHEMTs using the bilayer SiNx gate dielectric scheme for highly ef?cient power applications.
关键词： LPCVD,SiNx,bilayer,gate dielectric,MISHEMTs,GaN
更新于2025-09-04 15:30:14
-
Optical coupling between resonant dielectric nanoparticles and dielectric nanowires probed by third harmonic generation microscopy
摘要： Localized electromagnetic modes and negligible Ohmic losses dictate the growing interest to subwavelength all-dielectric nanoparticles. Although an exhaustive volume of literature dealt with interaction of all-dielectric nanostructures with free-space electromagnetic fields, they received little attention as integrated photonic elements. We present an experimental and numerical study of optical coupling between a resonant subwavelength silicon nanodisk and a silicon nanowire, as probed by third harmonic generation microscopy and full-wave simulations. First, by placing the nanodisks at different distances from the nanowire, we observed third harmonic intensity modulation by a factor of up to 4.5. This modulation is assigned to changes in the local field enhancement within the nanodisks caused by their coupling to the nanowires and subsequent shifting and broadening of their magnetic-type resonances. Interestingly, although the nanowire presents an additional loss channel for the nanodisk, we observed an increase in the local field strength within the nanodisk, as verified by rigorous full-wave simulations. Inversely, for the gap sizes that are smaller than ≈ 200 nm, we observe the influence of the nanoparticles on the propagation properties of the fundamental waveguide modes of the nanowire. The better understanding of the mutual influence of the Mie-resonant nanoparticles and waveguiding structures heralds integration of the former on photonic chips.
关键词： dielectric nanowire,third harmonic generation microscopy,silicon nanoparticles,Optical coupling
更新于2025-09-04 15:30:14
-
Synthesis of type-II based (1-x)Ba <sub/>0.6</sub> (Ca <sub/>1/2</sub> Sr <sub/>1/2</sub> ) <sub/>0.4</sub> Ti <sub/>0.5</sub> Fe <sub/>0.5</sub> O <sub/>3</sub> +(x)Ni <sub/>0.40</sub> Zn <sub/>0.45</sub> Cu <sub/>0.15</sub> Fe <sub/>1.9</sub> Eu <sub/>0.1</sub> O <sub/>4</sub> composites via standard solid state reaction method and investigation of multiferroic properties
摘要： A series of multiferroic composites, (1-x)Ba0.6(Ca1/2Sr1/2)0.4Ti0.5Fe0.5O3+(x)Ni0.4Zn0.45Cu0.15Fe1.9Eu0.1O4 ((1-x)BCSTFO+(x)NZCFEO) where x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 1.0 have been synthesized by standard double sintering ceramic method sintered for 3 hours at 1200?C in air. The X-ray diffraction patterns reveal that the multiferroics and the parent ceramic samples crystallize in simple cubic structure with a slightly distored lattice parameter. The X-ray and bulk density increase with the increasing ferrite content. Consequently, the porosity decreases indicating better crystallization. A decreasing trend in dielectric constant is observed while the relative quality factor (RQF) increases signi?cantly with the increasing ferromagnetic NZCFEO. At the same time, M–H hysteresis loops reveal that ferromagnetic property enhances with the addition of Ni0.40Zn0.45Cu0.15Fe1.9Eu0.1O4 (NZCFEO). The highest values of coercive ?eld ～ 92 O and saturation magnetization ～1.37 emu/g are observed for x = 10% and x = 50% compositions respectively. Additionally, the permeability enhances up-to x = 30% but decreases with further doping. The room temperature resistivity rises due to the decrease in hopping mechanism. The samples exhibit a decreasing trend for resistivity with the increase of temperature. The dopant concentration has also shown an impressive impact on the activation energy. As a result, the multiferroic properties of (1-x)BCSTFO+(x)NZCFEO have been signi?cantly improved considering the measured magnetic and ferroelectric properties.
关键词： multiferroic composites,resistivity,dielectric constant,permeability,ferromagnetic property
更新于2025-09-04 15:30:14
-
Surface Plasmon Resonance in a metallic nanoparticle embedded in a semiconductor matrix: exciton-plasmon coupling
摘要： We consider the effect of electromagnetic coupling between localized surface plasmons in a metallic nanoparticle (NP) and excitons or weakly interacting electron-hole pairs in a semiconductor matrix where the NP is embedded. An expression is derived for the NP polarizability renormalized by this coupling and two possible situations are analyzed, both compatable with the conditions for Fano-type resonances: (i) a narrow bound exciton transition overlapping with the NP surface plasmon resonance (SPR), and (ii) SPR overlapping with a parabolic absorption band due to electron-hole transitions in the semiconductor. The absorption band lineshape is strongly non-Lorentzian in both cases and similar to the typical Fano spectrum in the case (i). However, it looks differently in the situation (ii) that takes place for gold NPs embedded in a CuO film and the use of the renormalized polarizability derived in this work permits to obtain a very good fit to the experimentally measured LSPR lineshape.
关键词： Localized surface plasmon,Nanoparticle,Semiconductor,Dielectric function,Composite,Fano resonance,Exciton
更新于2025-09-04 15:30:14
-
[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Robust Design of Low Side Lobe Level Microstrip Antenna Array by Using Lossy Superstrate
摘要： The side lobe level (SLL) suppression technique using lossy superstrate for robust antenna design is proposed. It is conduct by optimizing the dielectric parameters (i.e., relative permittivity, thickness and loss tangent) based on the spectral Green’s function. To validate our method, a 2*2 microstrip antenna array loaded by 2-layer dielectric superstrate is optimized for low SLL. The optimization results show that using lossless dielectric superstrate the optimized SLL can reach -35.2 dB at 35 GHz without considering the fabrication error. Taking the available precision of air gap thickness ((cid:3399)0.02 mm) into consideration, the SLL is raised to -30.4 dB while using lossy superstrate it can be reduced to -35.6 dB at the cost of gain by 5.6 dB. With involving the effect of the feed network in the simulation, the SLL is deteriorated to -34 dB and is lower than -32.3 dB over the operating band from 34.65 GHz to 35.2 GHz.
关键词： robust design,lossy superstrate,Side lobe suppression,dielectric loaded antenna
更新于2025-09-04 15:30:14
-
[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Compact UWB Circularly Polarized Dielectric Rod Antenna Design
摘要： A novel circular-polarization (CP) ultra-wideband dielectric rod antenna design has been developed for operating from X to Ka band. The radiation tip design was based on the previous dual linear-polarization 3-layer dielectric rod design. A novel CP wave-launcher composed of conical spiral arms was developed. This launcher does not require balun or quadrature-phase hybrid. In addition, a novel quadrifilar conducting enclosure was introduced to minimize overall antenna diameter while maintaining good axial ratio at the low frequency end. The simulated antenna performance exhibits an axial ratio (AR) of less than 3 dB, stable gain, stable beamwidth, and stable phase center from 10 to 40 GHz.
关键词： Circular polarization,Ultra-wideband antennas,Dielectric antenna
更新于2025-09-04 15:30:14
-
[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Optimization of a Multi-Receiver FMCW Radar for Snow Cover Monitoring
摘要： Microwave radars represent an interesting solution to monitor the internal structure of the snow cover because the measurements are practically instantaneous, non-destructive, and can be remotely controlled to improve the safety of the operators. In particular, an innovative radar architecture based on two receivers can deliver, at the same time, the depth and the dielectric permittivity of the snow cover, this latter directly related to the physical parameters of the snow, such as the density. These parameters are fundamental to provide an accurate forecast for the avalanche formation. This paper presents the optimization of the dual-receiver radar architecture, in terms of the reciprocal distance between the transmitter and the receivers. Preliminary experimental results are also presented.
关键词： dielectric permittivity,stratigraphy,multi-receiver architecture,FMCW radar,monitoring,snow avalanche
更新于2025-09-04 15:30:14
-
[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Simple Surface-Wave Launching by Parallel-Plate and Microstrip Feeding for Leaky-Wave Antennas and Other Planar Guided-Wave Applications
摘要： A simple parallel-plate waveguide (PPW) with a microstrip feed is proposed for efficient TM0 surface-wave (SW) mode excitation. In particular, by means of a truncated PPW and a printed sub-wavelength matching section, phase constants can be tailored and matched at discontinuities. This surface-wave launcher (SWL) offers an attractive microstrip feeding approach to LWAs and is an alternative to more conventional feeding networks that are typically employed for dielectric image guides (DIGs) and other planar structures because of its good performance, low cost and simple implementation. The proposed SWL has been designed to operate at K and Ka bands in a substrate with a relative permittivity of 10.2. In order to validate its performance in a LWA or for other planar applications, several scenarios have been designed and simulated: an end-to-end test circuit, a 1-D LWA and a DIG feeder. High efficiency and wideband operation have been obtained for all these structures. The proposed SWL with a microstrip feed can also be useful for other planar wave guiding structures at microwave and millimeter-wave frequencies.
关键词： parallel plate waveguides,leaky-wave antennas,surface wave launcher,dielectric image guide
更新于2025-09-04 15:30:14
-
[IEEE 2018 International Semiconductor Conference (CAS) - Sinaia, Romania (2018.10.10-2018.10.12)] 2018 International Semiconductor Conference (CAS) - Second Harmonic Generation: A Non-Destructive Characterization Method for Dielectric-Semiconductor Interfaces
摘要： This paper reviews the application of second harmonic generation (SHG) to characterize dielectric-semiconductor interfaces in microelectronics and photovoltaics. Based on non-linear optics, the method is non-destructive, so particularly advantageous for thin films. The theoretical background shows the possibility to access the electric field at interfaces and consequently to have a non-destructive measurement for interface state densities or fixed charges in oxides. Two more detailed examples of application of SHG characterization will be shown: passivation of silicon using thin film deposited alumina and interface analysis of silicon-on-insulator substrates.
关键词： interface states,dielectric-semiconductor interfaces,fixed oxide charges,interface electric field,second harmonic generation
更新于2025-09-04 15:30:14
-
[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Multi-Frequency GNSS Dielectric Resonator Antenna with In-Band Filtering
摘要： This paper presents a novel multi-frequency GNSS antenna based on a dielectric resonator (DR) with in-band filtering. The antenna is based on a conventional hollow cylinder DR with four feeding ports. It introduces a novel concept so called "decoupling network". The "decoupling network" is an engineered surface conformal to the inner wall of the DR and it contributes to the antenna realized gain, impedance bandwidth and provides narrow-band notch-filter like suppression of antenna radiation between 1.34 and 1.41 GHz. In case of the GNSS antennas, the radiation suppression between 1.3 and 1.56 GHz is desirable to reject in-band interference from the L-band satellite and terrestrial communication signals. The "decoupling network" also contributes to the coupling reduction between the feeding ports.
关键词： GNSS antenna,compact antenna,broadband antenna,circular polarization,engineered surface,dielectric resonator,EBG
更新于2025-09-04 15:30:14