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- 2018
- GaN HEMTs
- Power amplifier
- Broadband power amplifier
- SC band
- Power combining
- concentrated capacitive load
- distribution of the complex current at the antenna
- broadband antenna
- standing wave voltage factor
- antenna gain factor
- Electronic Science and Technology
- Oles Honchar Dnipro National University
- University of Tehran
- Gdansk University of Technology
- V. N. Karazin Kharkiv National University
- Reykjavik University
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Theoretical investigation of broadband absorption enhancement in a-Si thin-film solar cell with nanoparticles
摘要： Thin-film solar cells have attracted increasing attention due to its low material cost and large flexibility, but they also face the challenge of low solar absorption due to reduced active layer thickness. Through exciting surface plasmon resonance, plasmonic metal nanoparticles are usually placed on the cell front surface to enhance solar absorption. However, if eliminating the unuseful intrinsic absorption in nanoparticles, we find that dielectric ones are better choices to enhance a-Si thin-film solar cell absorption efficiency. Moreover, a composite light trapping structure with dielectric nanoparticles on the front surface and metal hemispheres on the rear surface is proposed to achieve broadband absorption enhancement in both short and long wavelengths, with the aim to get a higher conversion efficiency. The finite-difference-time-domain simulation results show that, compared with bare 100-nm-thick amorphous silicon solar cell, the short-circuit current density and photoelectric conversion efficiency could be respectively improved by 21% and 18% with addition of optimized composite light trapping structure. The general method proposed in this study could provide valuable guidance to light trapping structure design for various kinds of thin-film solar cells.
关键词： Broadband absorption enhancement,Thin-film solar cell,Light trapping,Conversion efficiency,Amorphous silicon,Nanoparticle
更新于2025-09-19 17:13:59
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Spectral absorption control of femtosecond laser-treated metals and application in solar-thermal devices
摘要： Direct femtosecond (fs) laser processing is a maskless fabrication technique that can effectively modify the optical, electrical, mechanical, and tribological properties of materials for a wide range of potential applications. However, the eventual implementation of fs-laser-treated surfaces in actual devices remains challenging because it is difficult to precisely control the surface properties. Previous studies of the morphological control of fs-laser-processed surfaces mostly focused on enhancing the uniformity of periodic microstructures. Here, guided by the plasmon hybridisation model, we control the morphology of surface nanostructures to obtain more control over spectral light absorption. We experimentally demonstrate spectral control of a variety of metals [copper (Cu), aluminium (Al), steel and tungsten (W)], resulting in the creation of broadband light absorbers and selective solar absorbers (SSAs). For the first time, we demonstrate that fs-laser-produced surfaces can be used as high-temperature SSAs. We show that a tungsten selective solar absorber (W-SSA) exhibits excellent performance as a high-temperature solar receiver. When integrated into a solar thermoelectric generation (TEG) device, W-SSA provides a 130% increase in solar TEG efficiency compared to untreated W, which is commonly used as an intrinsic selective light absorber.
关键词： spectral light absorption,plasmon hybridisation model,selective solar absorbers,solar thermoelectric generation,broadband light absorbers,femtosecond laser processing
更新于2025-09-19 17:13:59
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Mixed-dimensional PdSe <sub/>2</sub> /SiNWA heterostructure based photovoltaic detectors for self-driven, broadband photodetection, infrared imaging and humidity sensing
摘要： The new discovery of two-dimensional (2D) palladium diselenide (PdSe2) films has attracted intensive research interest due to their unique asymmetric crystal structure and extraordinary optoelectronic properties, showing great potential for broadband and polarization photodetection. Herein, we have developed for the first time a self-driven, highly polarization-sensitive, broadband photovoltaic detector based on a PdSe2/Si nanowire array (SiNWA) heterostructure. Owing to the strong light confinement effect of the SiNWA and broadband light absorption of PdSe2, the present device exhibits pronounced photovoltaic behavior and excellent performance in terms of a high responsivity of 726 mA W?1, a large specific detectivity of 3.19 × 1014 Jones, an ultrabroad spectrum response range of 0.2–4.6 mm, and a fast response speed to monitor nanosecond pulsed light signals. Significantly, an impressive polarization sensitivity of 75 is achieved for the heterostructure device, which is among the highest for 2D material-based photodetectors. Thanks to the outstanding imaging capability, the detector can record images in both near infrared (NIR) and mid-infrared (MIR) ranges with a decent resolution. Moreover, the device exhibits light-enhanced humidity sensing behavior with a high sensitivity and a fast response/recovery time. Given these remarkable device features, the PdSe2/SiNWA heterostructure will hold great promise for high-performance, polarization-sensitive broadband photodetection, infrared imaging and humidity sensing applications.
关键词： humidity sensing,SiNWA,infrared imaging,photovoltaic detector,heterostructure,broadband photodetection,PdSe2
更新于2025-09-19 17:13:59
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Modeling of optical signal processing based on injection-locked broadband quantum cascade lasers
摘要： An all-optical signal processing approach has been presented which relies on gain competition between interconnected wavelengths in a broadband QCL. It has been shown that optical injection-locking, as the physical mechanism which modifies the inter-coupling between widely separated wavelengths, induces spectral reshaping through suppressing or raising the output intensity at intended wavelengths. Our developed model which is based on an experimental demonstration of an ultra-broadband QCL reveals a correlation between the intensity and modulation response of the injection-locked wavelengths. Also, it has been shown that logic operations and extremely wideband wavelength conversion between the mid and far-IR spectral regions of the laser can be accomplished.
关键词： Broadband cascade lasers,mid-infrared signal processing potential,Quantum cascade lasers
更新于2025-09-19 17:13:59
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Nanoplasmonics - Fundamentals and Applications || Impedance Matching Analysis of Cylindrical Plasmonic Nanoantennas Fed by Optical Transmission Lines
摘要： An impedance matching analysis of two plasmonic nanocircuits connected to cylindrical nanoantennas is presented. In the first case, a bifilar optical transmission line (OTL) with finite length is connected between two nanodipoles, where one is illuminated by an optically focused Gaussian beam (receiving dipole) and the other radiates energy received from the OTL (emitting dipole). In the second case, the OTL is fed by a voltage source on one side and connected to a dipole‐loop composed antenna on the other side. These circuits are analysed electromagnetically by the linear method of moments (MoM) with equivalent surface impedance of conductors. Some results are compared using the finite element method. The results show the impedance matching characteristics of the circuits as a function of their geometries and the broadband response of the second circuit due the broadband dipole‐loop antenna.
关键词： broadband nanoantennas,cylindrical nanoantennas,method of moments (MoM),impedance matching,plasmonic circuits
更新于2025-09-19 17:13:59
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Interlayer Transition in a vdW Heterostructure toward Ultrahigh Detectivity Shortwave Infrared Photodetectors
摘要： Van der Waals (vdW) heterostructures of 2D atomically thin layered materials (2DLMs) provide a unique platform for constructing optoelectronic devices by staking 2D atomic sheets with unprecedented functionality and performance. A particular advantage of these vdW heterostructures is the energy band engineering of 2DLMs to achieve interlayer excitons through type-II band alignment, enabling spectral range exceeding the cutoff wavelengths of the individual atomic sheets in the 2DLM. Herein, the high performance of GaTe/InSe vdW heterostructures device is reported. Unexpectedly, this GaTe/InSe vdWs p–n junction exhibits extraordinary detectivity in a new shortwave infrared (SWIR) spectrum, which is forbidden by the respective bandgap limits for the constituent GaTe (bandgap of ≈1.70 eV in both the bulk and monolayer) and InSe (bandgap of ≈1.20–1.80 eV depending on thickness reduction from bulk to monolayer). Specifically, the uncooled SWIR detectivity is up to ≈1014 Jones at 1064 nm and ≈1012 Jones at 1550 nm, respectively. This result indicates that the 2DLM vdW heterostructures with type-II band alignment produce an interlayer exciton transition, and this advantage can offer a viable strategy for devising high-performance optoelectronics in SWIR or even longer wavelengths beyond the individual limitations of the bandgaps and heteroepitaxy of the constituent atomic layers.
关键词： interlayer transitions,2D materials,vdW heterostructures,broadband photodetectors,shortwave infrared
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
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[IEEE 2019 12th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - London, United Kingdom (2019.8.20-2019.8.22)] 2019 12th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - A 400 GHz Broadband Multi-Branch Waveguide Coupler
摘要： Terahertz (THz) technology is a hotspot in current academic research. A 400 GHz broadband Multi-branch waveguide hybrid coupler is designed in this paper. Compared to 5-branch designs, the proposed hybrid consists of 7-branch and has been optimized to a great performance, which increases the operation bandwidth. Based on this model, the performance of the mixer is optimized by HFSS software. The simulation results show that the return loss (S11) and isolation (S23) are better than 20 dB in the frequency range of 350 GHz to 450 GHz, which is nearly 25% relative bandwidth, and the good performance of power splitting can also be seen from the amplitude and phase of S21 and S31.
关键词： passive circuit,broadband capabilities,Terahertz,3dB waveguide hybrid coupler
更新于2025-09-19 17:13:59
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[IEEE 2019 6th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR) - Xiamen, China (2019.11.26-2019.11.29)] 2019 6th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR) - A Ku-band Broadband Single-Ridge Waveguide Slot Antenna Array for UAV SAR Application
摘要： a Ku-band broadband waveguide wide side longitudinal slot antenna array for unmanned aerial vehicle (UAV) SAR application is designed. A single-ridge is employed to reduce the sectional size of the waveguide, and to achieve wide scanning ability. The bandwidth of the antenna is expanded by the single-ridge and subarea feeding of the slots. The active admittance of the waveguide slot is extracted based on the simulation using the HFSS software, in order to determine the size parameters of the waveguide slots. The simulation mode is built and the size parameters of the waveguide slots are modified and optimized by the aperture distribution re-deducing method. This design method has high efficiency and high veracity. An antenna array of 72 waveguide slot antenna lines is designed and manufactured. The measured results show that the relative bandwidth of VSWR smaller than 2 is 15%. The measured patterns show that the side lobe is smaller than -21.5dB, the cross polarization is better than -40dB, and the scanning angle is ±60° in azimuth direction. This waveguide slot antenna array has many advantages such as wide band, wide scanning, low side lobe and compact structure, and is suitable for UAV SAR application.
关键词： phased array antenna,single-ridge waveguide,waveguide slot antenna,broadband
更新于2025-09-19 17:13:59
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Two-stage optimal scheduling of air conditioning resources with high photovoltaic penetrations
摘要： Infrared chemical microscopy through mechanical probing of light?matter interactions by atomic force microscopy (AFM) bypasses the diffraction limit. One increasingly popular technique is photoinduced force microscopy (PiFM), which utilizes the mechanical heterodyne signal detection between cantilever mechanical resonant oscillations and the photoinduced force from the light?matter interaction. So far, PiFM has been operated in only one heterodyne configuration. In this Article, we generalize heterodyne configurations of PiFM by introducing two new schemes: harmonic heterodyne detection and sequential heterodyne detection. In harmonic heterodyne detection, the laser repetition rate matches integer fractions of the difference between the two mechanical resonant modes of the AFM cantilever. The high harmonic of the beating from the photothermal expansion mixes with the AFM cantilever oscillation to provide the PiFM signal. In sequential heterodyne detection, the combination of the repetition rate of laser pulses and the polarization modulation frequency matches the difference between two AFM mechanical modes, leading to detectable PiFM signals. These two generalized heterodyne configurations for PiFM deliver new avenues for chemical imaging and broadband spectroscopy at ～10 nm spatial resolution. They are suitable for a wide range of heterogeneous materials across various disciplines: from structured polymer film, to polaritonic boron nitride materials, to isolated bacterial peptidoglycan cell walls. The generalized heterodyne configurations introduce flexibility for the implementation of PiFM and the related tapping-mode AFM-IR and provide possibilities for an additional modulation channel in PiFM for targeted signal extraction with nanoscale spatial resolution.
关键词： photoinduced force microscopy,nanoscale spatial resolution,chemical imaging,Infrared chemical microscopy,heterodyne configurations,broadband spectroscopy
更新于2025-09-19 17:13:59