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[IEEE 2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting - Boston, MA, USA (2018.7.8-2018.7.13)] 2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting - An Origami Inspired Circularly-Polarized Folding Patch Antenna Array
摘要： This work investigates and develops the physical reconfiguration and deployment of a previously designed 2x2 corporate-fed microstrip patch antenna array. The physical reconfiguration of the antenna is achieved using a Miura-ori fold pattern due to its utilization for deployment. Increasing the fold angle impacts the input impedance and beamforming capabilities by changing the element spacing and orientation. The previous design experienced a graceful degradation in electromagnetic performance as the fold angle increased. Further optimization led to a more robust and functional antenna array system. The antenna is enhanced by designing the array with circularly polarized patch elements. The use of circular polarization eliminates the need to study the polarization changes during intermediate folding states and enables pattern reconfigurability. The performance of the circularly polarized array is evaluated over a comprehensive range of angles to evaluate the impact of physical reconfiguration. Results from a simulated circularly polarized array are provided for a 3GHz design.
关键词： multiphysics simulation,adaptive arrays,origami,microstrip antenna arrays
更新于2025-09-19 17:15:36
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Wideband Wide-Scanning Phased Array in Triangular Lattice with Electromagnetic Band-Gap Structures
摘要： A phased array in triangular lattice, with a large element spacing, wide band and wide scan angle, is investigated in this paper. The array is designed based on a connected backed-cavity antenna element. Scan blindness is observed for this triangular lattice array when the beam scans in the E plane due to large element spacing which provides a suitable propagation condition for the leaky surface waves in the array aperture. Therefore, compact electromagnetic band-gap (EBG) structures are loaded in the array element to suppress the leaky surface waves and then remove the E-plane scan blindness for the largest impedance bandwidth. The bandwidths close to the theoretical values are achieved as the beam is scanned in the E and H planes, for the given element spacing. The validity of design is verified by fabricating a 13×5 prototype, the measured results are in good agreements with the full-wave simulations.
关键词： scan blindness,phased arrays,wide scanning,Electromagnetic band-gap (EBG) structures,triangular lattice
更新于2025-09-19 17:15:36
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Synthesis of an algorithm for interference immunity
摘要： This paper discusses the synthesis of an algorithm for adaptive interference nulling of an 8-element phased antenna array. An adaptive beam-forming system has been built on the basis of the algorithm. The paper discusses results of experimental functioning of navigation satellite systems user equipment fitted with an adaptive phased antenna array in interference environments.
关键词： navigation satellite systems,adaptive nulling algorithms for phased antenna arrays,adaptive phased antenna array
更新于2025-09-19 17:15:36
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Rapid Quantitative Fluorescence Detection of Copper Ions with Disposable Microcapsule Arrays Utilizing Functional Nucleic Acid Strategy
摘要： In this work, an economical and easy-to-use microcapsule array fabricated by ice printing technique has been realized for ultrasensitive fluorescence quantification of copper ions employing functional nucleic acid strategy. With ice printing, the detection reagents are sealed by polystyrene (PS) film isolation and photopolymer, which guarantees a stable and contamination-free environment for functional nucleic acid reaction. Our microcapsule arrays have shown long-term stability (20 days) under ?20 °C storage in frozen form before use. During the Cu2+ on-site detection, 1 μL sample is simply injected into the thawy microcapsule by a microliter syringe under room temperature, and after 20 minutes the fluorescence result can be obtained by an LED transilluminator. This method can realize the detection limit to 100 nM (100 fmol/μL) with high specificity.
关键词： ice printing,functional nucleic acid,fluorescence detection,copper ions,microcapsule arrays
更新于2025-09-19 17:15:36
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[IEEE 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Chengdu (2018.3.26-2018.3.28)] 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Studies on Surface Plasmon Dispersion Theory on the Bilayer Graphene Ribbon Arrays Metasurface
摘要： Graphene surface plasmon polaritons (SPP) provide a promising platform to develop a series of new photonic, plasmonic and optoelectronic devices from terahertz to optic spectrum owing to its excellent properties. In this paper, a new kind of graphene metasurfaces, i.e., bilayer graphene ribbon arrays separated by a dielectric gap is proposed. The general dispersion theory of SPP mode on the structure is investigated by a modal expansion method. Solving field expressions on different regions and using proper periodic boundary conditions, the analytical dispersion expressions of SPP mode are obtained on the bilayer graphene ribbon arrays for the first time. With this result, the SPP characteristics of dispersion and propagation loss can be calculated and analyzed with graphene and structural parameters. The proposed SPP modes on the bilayer graphene ribbon arrays metasurface can open up new ways to develop some low-loss sub-wavelength plasmonic waveguide, planar retroreflectors and the enhanced terahertz radiation source.
关键词： surface plasmon polaritons,bilayer graphene ribbon arrays,periodic boundary,dispersion theory
更新于2025-09-19 17:15:36
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TiO2 nanotube arrays modified with nanoparticles of platinum group metals (Pt, Pd, Ru): enhancement on photoelectrochemical performance
摘要： Highly ordered TiO2 nanotube arrays (TiO2 NTs) were synthesized by anodization method using a titanium foil and further modified with nanoparticles (? = 2~10 nm) of three platinum group metals (that is, platinum, palladium, and ruthenium) through potentiostatic pulsed electrodeposition method to obtain the composite material. Compared with pure TiO2 NTs, all the three composite samples (M-TiO2 NTs, M = Pt, Pd, Ru) showed different enhancement effects on the light responses, as well as different photoelectrochemical performances. In this study, the performance of M-TiO2 NTs, which worked as photoanode and cathode, was investigated. Ru-TiO2 exhibited the best degradation yield (~ 85.8%) when applied as photoanode under visible light illumination, which indicated the platinum group metal could also be induced under visible irradiation, not just served as the co-catalyst. M-TiO2 NTs as cathode were evaluated under the hydrogen evolution reaction (HER). The three M-TiO2 NT electrodes showed an improved efficiency over pure TiO2 NTs, while Pt-TiO2 NTs performed even better (without any sacrificial agent) with higher Faradic efficiency than platinum electrode in the photoelectrocatalytic hydrogen production, which could be explained by the uniform and fine metal nanoparticles on the surface of TiO2 NTs to offer abundant active sites for the reaction.
关键词： Platinum group metal nanoparticles,Photoelectrocatalysis,Water splitting,Hydrogen production,TiO2 nanotube arrays
更新于2025-09-19 17:15:36
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Design of terahertz photoconductive antenna arrays based on defective photonic crystal substrates
摘要： In this paper, arrays of two different terahertz (THz) antennas based on defective photonic crystal (DPC) substrates are proposed and their radiation characteristics are investigated by using full-wave simulation. We show that employing DPC substrates in THz photoconductive antenna (PCA) arrays reduces the amount of power coupled to the substrate surface waves and, as a result, decreases the mutual coupling between the elements of the antenna array and increases the directivity in the boresight direction. By studying 1 × 2 arrays of bowtie and four-leaf-clover-shaped antennas, we show that either the improvement of directivity in a broad bandwidth or the enhancement of photomixer antenna impedance at a resonant frequency can be considered in the design of the DPC substrate. Therefore, the proposed approach can significantly improve the efficiency and radiation performance of THz photomixer antennas resulting in an improved effective THz radiated power in the desirable direction. The proposed DPC substrate can be considered as a way to realize sub-millimeter-sized dielectric resonator antennas at terahertz frequencies. In addition, this cost-effective technique can reduce the necessity of exploiting hyper-hemispherical Si lenses by overcoming the adverse effects of the thick substrate which is of prime importance in PCA arrays from a practical viewpoint.
关键词： Arrays,Defective photonic crystal substrate,Propagation waves,Terahertz antennas
更新于2025-09-19 17:15:36
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Hybridizing NiCo2O4 and amorphous NixCoy layered double hydroxides with remarkably improved activity towards the efficient overall water splitting
摘要： Overall water splitting is an attractive technology to produce clean hydrogen and oxygen. In this study, we constructed amorphous NixCoy layered double hydroxide (LDH) hybridized with three-dimensional NiCo2O4 to fabricate core-shell nanowire array on Ni foam (NiCo2O4@NixCoy LDH/NF) as highly efficient electrocatalyst for overall water electrolysis. By tuning the Ni/Co molar ratio in NixCoy LDH, extremely low overpotentials of 193 mV for oxygen evolution reaction (OER) and 115 mV for hydrogen evolution reaction (HER) at a current density of 10 mA cm?2 can be achieved for the NiCo2O4@Ni0.796Co LDH/NF. Detailed investigations verify that the hybrid structure can increase intrinsic activity of the NiCo2O4@Ni0.796Co LDH/NF and enhance the charge-transfer rate. Moreover, a strong electronic interaction between the heterogeneous elements Ni and Co at the interface of the NiCo2O4 and NixCoy LDH might ultimately influence the catalytic performance.
关键词： bifunctional electrocatalyst,nanowire arrays,amorphous material,layered double hydroxide,water splitting
更新于2025-09-19 17:15:36
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Explaining the enhanced photoelectrochemical behavior of highly-ordered TiO2 nanotube arrays: anatase/rutile phase junction
摘要： The effect of calcination temperature on the photoelectrochemical properties of TiO2 nanotube arrays (TNTAs) has been investigated in many studies. Most work focused on improving the photoelectrochemical properties through optimization of the microstructure. In this paper, however, an anatase/rutile phase junction formed in TiO2 nanotubes has been demonstrated to account for the enhancement of the photoelectrochemical performance. Observations by the UV-visible diffuse reflectance spectra, glancing incidence angle X-ray diffraction (GIA-XRD) and electrochemical impedance spectroscopy indicate that the rutile fraction is at the bottom of the nanotubes while the anatase fraction at the body of the nanotubes. The TNTAs with the coexistence of about 60% anatase and 40% rutile exhibit the optimal performance and show the 1.4 times improved photocurrent density compared with the pure anatase TNTAs. Detailed synchrotron radiation photoemission spectroscopy further confirms the existence and effect of the phase junction. The results suggest photogenerated electrons transfer from the rutile phase to anatase phase in the nanotubes due to the band edge alignment, which facilitates the photogenerated carriers separation and transport along the nanotubes and leads to apparent enhancement of the photoelectrochemical behavior.
关键词： photoelectrochemical properties,TiO2 nanotube arrays,phase junction,thermal treatment
更新于2025-09-19 17:15:36
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Biosensing Using Arrays of Vertical Semiconductor Nanowires: Mechanosensing and Biomarker Detection
摘要： Due to their high aspect ratio and increased surface to foot-print area, arrays of vertical semiconductor nanowires are used in numerous biological applications, such as cell transfection and biosensing. Here we focus on two specific, valuable biosensing approaches that, so far, have received relatively limited attention in terms of their potential capabilities: cellular mechanosensing and lightguiding-induced enhanced fluorescence detection. Although proposed a decade ago, these two applications for using vertical nanowire arrays have only very recently achieved significant breakthroughs, both in terms of understanding their fundamental phenomena, and in the ease of their implementation. We review the status of the field in these areas and describe significant findings and potential future directions.
关键词： mechanosensing,vertical nanowire arrays,fluorescence detection,biosensing,semiconductor nanowires
更新于2025-09-19 17:15:36