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- 2019
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- PCB techonology
- substrate integrated image line (SIIG)
- co-axial probe feeding
- single-layer transition
- millimeter wave devices
- short-slot coupler
- Substrate integrated waveguide (SIW)
- band-pass filters
- diplexer
- reconfigurable filter
- Optoelectronic Information Science and Engineering
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- Fujikura Ltd.
- University of Electronic Science and Technology of China
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- Hiroshima University
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Copper particle contamination detection of oil-immersed transformer using laser-induced breakdown spectroscopy
摘要： The deterioration of transformer oil caused by particle contamination, especially copper particle, seriously affects the safe operation of oil-immersed transformers. Therefore, it is very important for the detection of metal particles in transformer oil. A new method based on laser-induced breakdown spectroscopy (LIBS) was first applied in the transformer oil diagnosis field. By screening out effective spots, the correlation between Cu particle concentration and LIBS signal was obtained after testing a set of oil samples with concentration range from 0.54 to 12.4 μg/g; the calibration curves of Cu I 324.75 nm / CN 358.6 nm and Cu I 327.39 nm /CN 358.6 nm were therefore established. The results shown high linearity, and the determination coefficient R2 of the two calibration curves in range from 0.54 to 3.1 μg/g were superior to 0.99. The limit of detection (LOD) inferred from Cu I 324.75 nm /CN 358.6 nm fitting curve was 0.77 μg/g and met the critical value specified by industry standards. Due to its flexibility, it can be used as a new-type of particle concentration detection method for transformer oil.
关键词： copper particle,filter paper substrate,transformer oil,laser-induced breakdown spectroscopy
更新于2025-09-19 17:13:59
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Cold substrate method to prepare plasmonic Ag nanoparticle: deposition, characterization, application in solar cell
摘要： In this study, the surface plasmon effects of the Ag nanoparticle were investigated depending on the substrate temperature and coating time. Deposition procedure for the Ag coating was the vacuum deposition at low substrate temperature (< 300 K) instead of the commonly used the vacuum deposition at high substrate temperatures. The Ag thin films were deposited on n-type Si, glass and solar cell with safety glass substrates. The structural and optical characteristics of the Ag thin films prepared on Si and glass substrates were investigated. The Ag thin films had a polycrystalline structure with cubic phase. The (111) preferred orientation for 300 K substrate temperature was changed to (200) after 200 K substrate temperature. Homogeneous nano-sized Ag particles on Si were obtained at the 150–200 K temperature range. Optical measurements were performed for the Ag thin films prepared on glass substrates. According to reflectance measurements, plasmon resonance effect of the Ag nanoparticles was observed around 435–540 nm. The Ag nanoparticles prepared on solar cell at low substrate temperature increased the solar cell efficiency for all coating time because the nanoparticle size and shape were not changed significantly with the coating time. However, the Ag thin films prepared at high substrate temperature decreased device efficiency with the increasing coating time.
关键词： Surface plasmon resonance,Ag nanoparticle,Vacuum evaporation,Solar cell,Cold substrate
更新于2025-09-19 17:13:59
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Control of Charge Carrier Dynamics in Plasmonic Au Films by TiO <sub/><i>x</i> </sub> Substrate Stoichiometry
摘要： Plasmonic excitations in noble metals have many fascinating properties and give rise to a broad range of applications. We demonstrate, using non-adiabatic molecular dynamics combined with time-domain density functional theory, that chemical composition and stoichiometry of substrates can have a strong influence on charge dynamics. By changing oxygen content in TiO2, including stoichiometric, oxygen rich and oxygen poor phases, and Ti metal, one can alter lifetimes of charge carriers in Au by a factor of 5, and control the ratio of electron-to-hole relaxation rates by a factor of 10. Remarkably, a thin TiOx substrate alters so much charge carrier properties in much thicker Au films. Such large variations stem from the fact that the Ti and O atoms are much lighter than Au, and their vibrations are much faster at dissipating the energy. The control over a particular charge carrier and an energy range depends on the Au and TiOx level alignment, and the interfacial interaction strength. These factors are easily influenced by the TiOx stoichiometry. In particular, oxygen rich and poor TiO2 can be used to control holes and electrons, respectively, while metallic Ti affects both charge carriers. The detailed atomistic analysis of the interfacial and electron-vibrational interactions generates the fundamental understanding of the properties of plasmonic materials needed to design photovoltaic, photocatalytic, optoelectronic, sensing, nanomedical and other devices.
关键词： non-adiabatic molecular dynamics,substrate layers,time-domain density functional theory,metallic films,electron-phonon energy relaxation,surface plasmons
更新于2025-09-19 17:13:59
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Porous POM/PLLA membranes decorated with gold nanoparticles as flexible and efficient plasmonic substrates for surface-enhanced Raman scattering
摘要： In this work, we have developed a flexible and efficient Surface-enhanced Raman scattering (SERS) substrate by a facile way of fabricating gold nanoparticles (NPs) decorated Poly(oxymethylene)/poly(L-lactic acid) (POM/PLLA) membranes. Firstly, POM/PLLA membranes were aminolyzed by1,6-hexanediamine to render the membranes with amino groups and porous structure simultaneously. The membranes were then immersed in tetrachloroauric acid (H4AuCl4) solution, where the AuCl4 anions were able to complex with the free amine groups of POM/PLLA, followed by in situ reduction by sodium borohydride to immobilize Au NPs on POM/PLLA membranes. The POM/PLLA/Au membranes exhibited high SERS sensitivity as well as good Raman signal reproducibility for rhodamine 6G (R6G). The minimum detection concentration was 10?14 M and the enhancement factor was calculated to be 1.54 × 109.
关键词： Poly(L-lactic acid),Flexible,SERS substrate,Membranes,Poly(oxymethylene)
更新于2025-09-19 17:13:59
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Solution-processed one-dimensional CsCu <sub/>2</sub> I <sub/>3</sub> nanowires for polarization-sensitive and flexible ultraviolet photodetectors
摘要： Polarization-sensitive ultraviolet (UV) photodetectors are highly desired due to their great significance in many applications. As the newly-emerging functional semiconductors, the metal-halide perovskites have attracted huge attention in photodetection due to their excellent optoelectronic features. However, the ever-reported perovskites polarized photodetectors mainly focused on the visible/infrared-light region, and the devices targeted at the UV region have not been reported. Here, for the first time, ternary copper halides CsCu2I3 nanowire was used as the light absorber to achieve polarization-sensitive UV photodetection. By combining the intrinsic anisotropy of the asymmetry structure and external morphology anisotropy of CsCu2I3 nanowires, a record photocurrent anisotropy ratio of ~3.16 was achieved, and also the shortcomings of lead-toxicity and environmental instability for conventional lead-halide perovskites were overcome effectively. Moreover, such photodetectors fabricated on flexible substrate demonstrate good flexibility and stability, showing almost no photoresponse degradation after extremely bending for 1000 cycles. The results suggest that the lead-free CsCu2I3 nanowire is potentially an attractive candidate for high-performance polarization-sensitive UV photodetectors compatible for practical applications.
关键词： CsCu2I3 nanowires,Polarization-sensitive,metal-halide perovskites,lead-free,ultraviolet photodetectors,flexible substrate
更新于2025-09-19 17:13:59
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Center frequency and bandwidth switchable substrate integrated waveguide filters
摘要： This paper presents center frequency and bandwidth switchable substrate integrated waveguide filters loaded with PIN diodes. The diodes are added in the slot on the surface of the resonators to switch the resonant frequencies and the coupling coefficients. Although the introduction of the slot causes extra radiation loss, it is small and acceptable. The proposed center frequency switchable filter has four center frequency switchable states of 1.78, 1.82, 1.88, and 1.91 GHz, while the bandwidth only changes ±0.64%. The bandwidth switchable filter has two states with 3 dB bandwidths of 70 and 103 MHz at a center frequency of 2.08/2.09 GHz. The measured performance of the fabricated filters shows good agreement with the simulation.
关键词： PIN diode,substrate integrated waveguide,switchable
更新于2025-09-19 17:13:59
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Dual-band substrate integrated waveguide dual-dumbbell-shaped-slot-fed patch antenna
摘要： A dual-band low-profile substrate integrated waveguide (SIW) dual-dumbbell-shaped-slot-fed (DDSSF) patch antenna is presented in this letter. The antenna is designed using the dual-dumbbell-slot feeding structure in SIW and two patches to radiate. And it achieves two passbands by exciting two modes of dual dumbbell-shaped slots (DDSSs). The first impedance bandwidth is 4.1%, the second one is 10.0% and gains up to 6.7 dBi and 7.4 dBi, respectively. Furthermore, the two bands can be separated from each other and the cross-polarization level is below ?30 dB. The simulation and measurement results of the proposed antenna are in good agreements.
关键词： slot,substrate integrated waveguide (SIW),dumbbell-shaped,dual-wide-band,low cross-polarization
更新于2025-09-19 17:13:59
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Design of a substrate integrated waveguide matrix amplifier
摘要： Developments in microwave systems have increased the need for matrix amplifiers, which provide both high gain and wide frequency bands. The aim of this paper is to design a novel 2 (cid:2) 4 matrix amplifier with a substrate integrated waveguide (SIW)-based power divider and combiner and a microstrip gain equalizer in the X and low Ku frequency bands. The proposed amplifier can be easily integrated with any microstrip, rectangular waveguide, or SIW-based circuits. The analysis and design of the amplifier is performed using two full wave simulators with different computational techniques (finite element method and finite integration technique) to verify the results. Simulation results show that the amplifier provides 16 dB gain with less than 4 dB ripple and more than 10 dB of input and output return losses in the frequency band of 8–15 GHz. This amplifier can be used as a wide band and high gain block in many microwave applications.
关键词： substrate integrated waveguide,distributed structure,Matrix amplifier,gain-bandwidth improvement
更新于2025-09-19 17:13:59
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Effect of Laser Loop on Surface Morphology of Copper Substrate and Wettability of Solder Joint
摘要： The effect of different laser loop parameter on the geometry of micro-groove pattern on copper substrate and its effect on the wettability was investigated. The micro-grooves pattern was fabricated on the copper surface through laser surface texturing process. 3D measuring laser microscope and contact angle measurement test was conducted to measure the geometry of the micro-grooves pattern and wettability of the solder joint respectively. The results showed that the improvement in laser loop parameter increased the depth of the micro-grooves due to the more exposed time which allows more material ablation. It also showed that the contact angle of textured substrate is smaller than the untextured substrate which results in better wettability.
关键词： wettability,laser loop,copper substrate,solder joint,surface morphology
更新于2025-09-19 17:13:59
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Broadband Eight-Way Substrate Integrated Waveguide Radial Power Divider/Combiner With High-Isolation
摘要： A broadband eight-way substrate integrated waveguide (SIW) radial power divider/combiner with high-isolation is presented. The step probes are utilized to achieve broadband impedance matching and improve the return loss. What’s more, the star structure based on microstrip circuit is employed to improve the isolation performance. A two-layer SIW radial power divider/combiner is designed, fabricated and measured. Good agreement between simulated and measured results is achieved for the proposed power divider/combiner. The measured results show that both bandwidths of the input and output port are 25% and 20% when their return loss are lower than -15 dB. The measured output isolation is greater than 17.5 dB from 5.75 GHz to 7.85 GHz and greater than 20 dB from 6.8 GHz to 7.9 GHz. The presented eight-way SIW power divider/combiner has the advantage of wider bandwidth, lower return loss and insertion loss, and higher isolation between the outputs.
关键词： high-isolation,Power divider/combiner,broadband,substrate integrated waveguide
更新于2025-09-19 17:13:59