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[IEEE 2019 IEEE International Conference on Microwaves, Antennas, Communications and Electronic Systems (COMCAS) - Tel-Aviv, Israel (2019.11.4-2019.11.6)] 2019 IEEE International Conference on Microwaves, Antennas, Communications and Electronic Systems (COMCAS) - Overview of High Frequency Electronics Integration Concepts for Gap waveguide based High Gain Slot Antenna Array
摘要： This paper presents an overview of different low-loss microstrip to waveguide transition designs suitable for integrating millimeter wave electronics to a gap waveguide based slot array. Typically, E-plane probe type of transitions are widely used at mmWave frequency range to couple RF signal from a TX/RX MMIC to the waveguide section. H-plane split-blocks are avoided due to leakage problem from tiny slits formed by imperfect metal connections. On the other hand, the traditional slot arrays are built using H-plane split blocks. This makes it very challenging to integrate electronics and other passive components such as diplexer filter directly to a high gain planar antenna array. To overcome this above mentioned problem, we propose to use low-loss H-plane transitions to integrate RF electronics with the multi-layer gap waveguide based slot array. We demonstrate a completely packaged front-end at E-band, showing the potential of the gap waveguide technology to build a very compact full-duplex wireless system.
关键词： E-plane transition,Slot arrays,Full-duplex,Integration and packaging,Gap waveguide
更新于2025-09-23 15:21:01
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Complete trapping of light with asymmetric plasmonic resonator arrays
摘要： Trapping/absorption of light in metallic micro/nano-structures on a dielectric-interspaced metal layer were widely studied, but discrepancies in results suggests uncertainty in its perfectness. Here we propose a modified structure with asymmetric resonance elements in each unit cell for complete trapping/absorption of light. In principle, the coupled asymmetric resonators oscillate anti-symmetrically under a critical matching condition, such that leaky radiations from the resonance elements are fully canceled in the far field, which results in guaranteed complete trapping/absorption of light in the near field. The structure may be applied in optoelectronic and bio-chemical sensing devices for strong light–matter interactions.
关键词： plasmonic resonator arrays,light trapping,optoelectronic devices,bio-chemical sensing,asymmetric resonators
更新于2025-09-23 15:21:01
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Surface Modification on Nanoripple-like ZnO Nanorod Arrays Using Two-dimensional (2D) Bi2OS2 to Fabricate High-Performance Inverted Polymer Solar Cells
摘要： In this paper, three-dimensional (3D) nanoripple-like ZnO nanorod arrays (R-ZnO NRAs) are successfully fabricated and modified by two-dimensional (2D) Bi2OS2 material, and inverted polymer solar cells (IPSCs) with R-ZnO modified by Bi2OS2 as electron transmission layer (ETL) are fabricated for the first time. The results show that the surface morphologies of R-ZnO NRAs can be controlled by adjusting the concentration of the modified 2D Bi2OS2 solution. Bi2OS2 modification can not only suppress the surface defects of R-ZnO NRAs, reduce the recombination of photogenerated charges, but also increase crystallinity of the active layer, resulting in effective electron collection. And thus, the performance of IPSCs is obviously improved. The power conversion efficiency (PCE) of PTB7: PCBM based PSCs with R-ZnO NRAs modified by 2% Bi2O2S as ETL is considerably raised to 7.31% from 5.51%. More interestingly, Bi2OS2 modification enhances IPSCs stability to remain 80.9% of their initial PCE after 80 days, yet IPSCs with pristine R-ZnO NRAs remain only 47.4% of their initial PCE. Moreover, this approach can also successfully improve the performance of another IPSC composed of PBDB-T: ITIC blends. The PCE of the device based on 2% Bi2OS2-modified R-ZnO NRAs is improved to 9.94% from 8.03% of the reference device without Bi2OS2 modification. This work not only provides an effective mean of surface modification of R-ZnO NRAs, but also shows the Bi2OS2 material has potential application in PSCs.
关键词： Recombination,Bi2OS2 nanosheets,Inverted polymer solar cells,Nanoripple-like ZnO nanorod arrays
更新于2025-09-23 15:21:01
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Multipoint Nanolaser Array in an Individual Core-Shell CdS Branched Nanostructure
摘要： Nanoscale laser arrays are attractive for their potential applications in highly integrated nanodevices, which are always obtained by nanowire arrays with complicated fabrication techniques. Here, a quite different nanolaser array is successfully realized based on a highly ordered core–shell CdS branched nanostructure with implanted Sn nanoparticles in junctions that split the individual multichannel nanostructures to various microcavities with effective light confinement and oscillation, thus to achieve a multipoint nanolaser array. Under the excitation of an ultraviolet laser, the strong band-edge emission can be well reflected between Sn nanoparticles at junctions and effectively scattered into branch segments due to Sn nanoparticles existence in junctions, furthermore oscillating in various microcavities along trunks or branches to form multipoint lasing from Fabry-Pérot (F-P) mode with a quality factor up to 990 and the low threshold at around 3.78 MW cm?2. The corresponding fluorescent microscope images further demonstrate the formation of multipoint F-P lasing at various segments. The theoretical simulation indicates that implanted Sn nanoparticles work as hot point to enhance the confinement of light around the Sn centers. The existence of surface plasmon from the Sn metal particles is further confirmed by the polarization dependent photoluminescence measurement. The results provide a new way to realize nanolaser arrays.
关键词： core–shell structures,CdS branched nanostructure,nanolaser arrays,electric field distribution
更新于2025-09-23 15:21:01
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Brazing, Laser, and Electron-Beam Welding of Additively Manufactured GRCop-84 Copper for Phased Array Lower Hybrid Launchers
摘要： Recent advances in selective laser melting 3-D printing technology allow additive manufacturing of lower hybrid current drive (LHCD) RF launchers from a new material, Glenn Research Copper 84 (GRCop-84), a Cr2Nb (8 at. % Cr, 4 at. % Nb) precipitation hardened alloy, in configurations unachievable by conventional machining. Cr2Nb crystals pin grain boundaries within the copper matrix resulting in high tensile strength and resistance to annealing at elevated temperatures. Brazing, laser, and electron-beam welding (EBW) techniques are explored for joining a thin-walled GRCop-84 waveguide with zero porosity and minimal internal surface roughness. GRCop-84 wets well with the silver solder, CuSil, and Cusil-ABA brazes, once the durable surface oxide is mechanically removed. GRCop-84 melt pool size and flow during EBW is reduced compared to oxygen-free copper (OFC). Pulsed laser and e-beam welding maintains the Cr2Nb precipitate size; precipitate coarsening occurs in conduction mode e-beam welding.
关键词： joining processes,fusion reactor design,magnetic confinement,Annealing,tokamaks,copper alloys,melt processing,materials processing,phased arrays,waveguide
更新于2025-09-23 15:21:01
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Nanoplasmonics || Plasmonic Nanoantenna Array Design
摘要： Recently, wireless optical communication system is developing toward the chip level. Optical nanoantenna array in optical communication system is the key component for radiating and receiving light. In this chapter, we propose a sub-wavelength plasmonic nanoantenna with high gain operating at the standard optical communication wavelength of 1550 nm. The designed plasmonic antenna has a good matching with the silicon waveguide in a wide band, and light is fed from the bottom of the nanoantenna via the silicon waveguide. Furthermore, we design two kinds of antenna arrays with the proposed plasmonic nanoantenna, including one- and two-dimensional arrays (1 × 8 and 8 × 8). The radiation characteristics of the antenna arrays are investigated and both arrays have high gains and wide beam steering range without grating lobes.
关键词： localized surface plasmon,radiation characteristics,integrated photonic devices,plasmonic nanoantenna,integrated optical antenna arrays
更新于2025-09-23 15:21:01
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Efficient Orthogonal Control of Tunnel Couplings in a Quantum Dot Array
摘要： Electrostatically-defined semiconductor quantum dot arrays offer a promising platform for quantum computation and quantum simulation. However, crosstalk of gate voltages to dot potentials and interdot tunnel couplings complicates the tuning of the device parameters. To date, crosstalk to the dot potentials is routinely and efficiently compensated using so-called virtual gates, which are specific linear combinations of physical gate voltages. However, due to exponential dependence of tunnel couplings on gate voltages, crosstalk to the tunnel barriers is currently compensated through a slow iterative process. In this work, we show that the crosstalk on tunnel barriers can be efficiently characterized and compensated for, using the fact that the same exponential dependence applies to all gates. We demonstrate efficient calibration of crosstalk in a quadruple quantum dot array and define a set of virtual barrier gates, with which we show orthogonal control of all interdot tunnel couplings. Our method marks a key step forward in the scalability of the tuning process of large-scale quantum dot arrays.
关键词： quantum simulation,quantum dot arrays,tunnel couplings,quantum computation,crosstalk compensation
更新于2025-09-23 15:21:01
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Optimizing the light delivery of linear-array-based photoacoustic systems by double acoustic reflectors
摘要： Although linear transducer arrays have been intensely used in photoacoustic imaging, their geometrical shape constrains light illumination. Today, most linear array based photoacoustic systems utilize side-illumination geometry, which consists of two line fiber bundles attached to the side of the probe. The angled light illumination increases the light travel distance in deep tissue, consequently limiting the imaging depth. This issue was partially addressed by adding a right angle prism in front of the transducer. While this design makes the light illumination and acoustic detection co-axial, the transducer and the fiber bundles are orthogonal to each other, making the system inconvenient for handheld use. To overcome this limitation, here we propose a double-reflector design, in which the second reflector redirects the acoustic signals by another 90°, so that the transducer and the fiber bundle are now parallel to each other. In this design, both the transducer and fiber bundle output are fitted into a compact housing for convenient handheld imaging. To evaluate the efficiency of our design, we performed various phantom and human in vivo experiments. Our results demonstrate that the double-reflector design indeed provides deeper imaging depth and it also allows for easy imaging of objects with uneven surfaces.
关键词： handheld imaging,photoacoustic imaging,co-axial illumination,double-reflector design,linear transducer arrays
更新于2025-09-23 15:21:01
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Photonic integrated multiwavelength laser arrays: Recent progress and perspectives
摘要： With the significant technology advancement in photonic integration and the demands of compact light sources of multiple wavelengths, multiwavelength laser arrays (MWLAs) can play important roles in high-capacity optical signal transmission, photonic switching, and optical sensing. Manufacturing with semiconductor foundries and the integration with electronic integrated circuits bring not only advanced technologies but also new concepts for realizing MWLAs. This paper will first overview the existing technology development and then discuss the challenges and possible solutions for enabling photonic-integrated MWLAs. The overview will cover monolithically and hybrid-integrated MWLAs. The wavelength registration for both in-plane and vertical-cavity MWLAs will be discussed and compared.
关键词： photonic switching,optical signal transmission,optical sensing,multiwavelength laser arrays,photonic integration
更新于2025-09-23 15:21:01
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Vein detection with near-infrared organic photodetectors for biometric authentication
摘要： We combine a low dark current and high-detectivity near-infrared (NIR)-sensitive organic photodetector with a high-resolution 508 pixels per inch (ppi) oxide thin-film transistor (TFT) backplane to create a large-area thin NIR detector, using processes that are compatible with flat-panel display fabrication. The detector is characterized showing high uniformity and linearity. With the use of a NIR light source, the detector is capable of imaging the (pattern of) veins under the skin in reflection, leading to improved biometric authentication.
关键词： near-infrared organic photodiodes,vein detection,biometric authentication,large-area photodetector arrays
更新于2025-09-23 15:21:01