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A Wideband Planar Aperture Array Using Interconnected Crossed Rings
摘要： A 5:1 frequency bandwidth aperture array antenna based on a new planar structure is reported. Dual polarization is implemented with high cross-polarization discrimination over ±45? scan angle from zenith. It is a low-loss cost effective approach using minimum dielectric materials. In the proposed planar antenna array design, a mutual coupled interconnected ring structure is used which extends the operational frequency band to the region where the element separation can be considerably greater than half a wavelength, unlike the previously reported interconnected array structures. Hence the total number of elements can be reduced for a speci?ed aperture size. The dual polarization have coincident-phase centers and in the implemen-tation reported here two low noise ampli?ers on the same board are integrated with a pair of dual polarized elements to form an active array. A 10 by 10 element array prototype of the design has been manufactured and the measured results con?rm it as a low cost, high performance front-end solution.
关键词： Aperture antennas,Phased arrays,Planar arrays,Radio astronomy
更新于2025-09-23 15:21:21
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Miniaturized Planar Sensor Development
摘要： This paper describes the process of developing a miniature device with planar sensors utilizing electrical capacitance measurement. The project investigates the feasibility and characterization of a miniaturized planar sensor integrated on a polydimethylsiloxane (PDMS) chamber. A 16-planar-electrodes array, with each dimension of the electrode, 4 mm × 2 mm (length × width) was fabricated using a printed circuit board (PCB) technology due to its low cost advantage. The measurement chamber for the sensing area was fabricated using PDMS. The PDMS chamber was bonded on the PCB with a semi cured PDMS to create a round sensing area for sample loading. The mould to develop the PDMS chamber was designed using AutoCAD 2010 and was fabricated using a 3D printer. Capacitance measurement of the planar electrodes was carried out using water as the sample and was validated using a theoretical calculation. Experimental result shows that the distance of the measured electrodes is inversely proportional to the capacitance value. The range of the measured capacitances of the measurement varies from 10 pF to 20 pF. The result shows that the planar sensors are able to provide capacitance measurement within the miniaturized platform where the measured capacitance showed good agreement with the theoretical calculation.
关键词： printed circuit board (PCB),Planar sensors,capacitance measurement,polydimethylsiloxane (PDMS)
更新于2025-09-23 15:21:21
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Arl13b Interacts With Vangl2 to Regulate Cilia and Photoreceptor Outer Segment Length in Zebrafish
摘要： Mutations in the gene ARL13B cause the classical form of Joubert syndrome, an autosomal recessive ciliopathy with variable degrees of retinal degeneration. As second-site modifier alleles can contribute to retinal pathology in ciliopathies, animal models provide a unique platform to test how genetic interactions modulate specific phenotypes. In this study, we analyzed the zebrafish arl13b mutant for retinal degeneration and for epistatic relationships with the planar cell polarity protein (PCP) component vangl2. Photoreceptor and cilia structure was examined by light and electron microscopy. Immunohistochemistry was performed to examine ciliary markers. Genetic interactions were tested by pairwise crosses of heterozygous animals. Genetic mosaic animals were generated by blastula transplantation and analyzed by fluorescence microscopy. At 5 days after fertilization, photoreceptor outer segments were shorter in zebrafish arl13b?/? mutants compared to wild-type larvae, no overt signs of retinal degeneration were observed by light or electron microscopy. Starting at 14 days after fertilization (dpf) and continuing through 30 dpf, cells lacking Arl13b died following transplantation into wild-type host animals. Photoreceptors of arl13b?/?;vangl2?/? mutants were more compromised than the photoreceptors of single mutants. Finally, when grown within a wild-type retina, the vangl2?/? mutant cone photoreceptors displayed normal basal body positioning. We show that arl13b?/? mutants have shortened cilia and photoreceptor outer segments and exhibit a slow, progressive photoreceptor degeneration that occurs over weeks. The data suggest that loss of Arl13b leads to slow photoreceptor degeneration, but can be exacerbated by the loss of vangl2. Importantly, the data show that Arl13b can genetically and physically interact with Vangl2 and this association is important for normal photoreceptor structure. The loss of vangl2, however, does not affect basal body positioning.
关键词： Arl13b,planar polarity,photoreceptor,cilia,zebrafish,retina,Vangl2
更新于2025-09-23 15:21:21
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ALMOST PERIODIC LUMPED ELEMENTS STRUCTURE MODELING USING ITERATIVE METHOD: APPLICATION TO PHOTONIC JETS AND PLANAR LENSES
摘要： In this work, we show that it is possible to produce a planar electromagnetic jet using a ?at structure consisting of elementary cells based on lumped elements and fed with a source line. A combination of elementary cells may represent a gradient index, locating the electromagnetic energy in a small area, consisting of a few cells and having a size of about 0.75λ. The theoretical framework of the study is based on the Wave Concept Iterative Process method (WCIP) formulated in both spectral and spatial domains. An analogy with an optical model based on optical paths equality enables predicting the location of formation of this spot. The use of such a system can provide solutions for the development of new kinds of applications such as engraving sub-wavelength, data storage, improved scalpel optics for ultra-precise laser surgery, and detection of cancer.
关键词： planar lenses,photonic jets,Wave Concept Iterative Process method,planar electromagnetic jet,lumped elements
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - The Influence of Terahertzand Middle-Infrared Laser Radiationon the Membrane-Dependent Properties of Ratsa?? Red Blood Cells
摘要： A novel planar ultrathin electronically steerable parasitic array radiator (ESPAR) is presented in this paper. Through theoretical analysis of the electric fields of orthogonally crossed dipoles in phase quadrature, it is found that the crossed dipoles radiate linearly polarized wave with a rotational electric field in the azimuth plane. This characteristic is then utilized to design a planar crossed dipole ESPAR, termed as “CD-ESPAR.” Furthermore, a simple but effective impedance matching method is also proposed and analyzed. To verify these concepts, a prototype with compact size and very low profile (0.42 λ0 × 0.42 λ0 × 0.006 λ0) resonating at 2.3 GHz is designed, fabricated, and measured. The measured results indicate that the proposed antenna achieves more than 17.8% impedance bandwidth and can produce four directional beams, covering the whole azimuth plane. Owing to its planar ultrathin structure, compact size, electronically beam-switching ability, low power, and low cost characteristics, it is promising for applications in wireless communications.
关键词： Beam-switching,planar antenna,smart antenna,crossed dipoles,electronically steerable parasitic array radiator (ESAPR)
更新于2025-09-23 15:21:01
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Evaluation of nitric oxide laser-induced fluorescence thermometry techniques in a hypersonic boundary layer
摘要： Nitric oxide planar laser-induced fluorescence was performed to measure the wall-normal distribution of static temperature through a hypersonic boundary layer. A 10-degree half-angle wedge model was oriented at a 5-degree angle of attack in the NASA Langley 31-in Mach 10 facility, resulting in a 5-degree flow turning angle and an edge Mach number of 7.6. Nitric oxide was seeded through a spanwise slot into the boundary layer upstream of the imaging region and was excited with a pulsed ultraviolet planar laser sheet. The laser was spectrally scanned across six fluorescence transitions in the (0, 0) band of the A2Σ+–X2Π system. Eighteen thermometry methods were assessed through comparison to predictions of the temperature field from computational fluid dynamics simulations. The effect of spectral resolution and laser linewidth on measurement uncertainty was also investigated. The most accurate technique was spectral peak thermometry, which achieved an accuracy of ± 31.6 K (12.6% error relative to CFD temperature). The spectral peak thermometry technique required a minimum spectral resolution between 0.074 and 0.102 cm?1 to extract meaningful temperature information from the spectra and a maximum laser linewidth of 0.49 cm?1.
关键词： Laser linewidth,Thermometry,Spectral resolution,Planar laser-induced fluorescence,Hypersonic boundary layer,Nitric oxide
更新于2025-09-23 15:21:01
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Light-induced transition between the strong and weak coupling regimes in planar waveguide with GaAs/AlGaAs quantum well
摘要： Exciton-polaritons in planar waveguides are of great interest for application in polariton circuits due to the large polariton group velocity in the plane of the waveguide. We demonstrate the ability to control the exciton-polariton coupling by light in an AlGaAs-based planar waveguide with GaAs/AlGaAs quantum well. The transition between strong and weak coupling regimes observed with increasing light intensity is explained by the increase in exciton mode losses due to the quantum well charging. This assumption is confirmed by the reflection spectroscopy with resonant illumination.
关键词： AlGaAs,GaAs,planar waveguides,strong coupling,quantum well,exciton-polaritons,weak coupling
更新于2025-09-23 15:21:01
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Planar multifrequency mid-IR microwave-pumped lasers
摘要： The characteristics of planar repetitively pulsed diffusion-cooled HF, DF, HF – DF, Xe, and HF – DF – Xe(Kr) lasers pumped by a microwave discharge (2.45 GHz) are studied depending on the pump pulse duration (10 – 40 ms) and repletion rate (50 – 400 Hz), as well as on the composition and pressure of the working gas mixture (30 – 200 Torr) at low (to 0.6 L s–1) gas flow rates. It is demonstrated for the first time that a HF – DF – Xe gas-discharge laser may simultaneously operate as a HF – DF chemical molecular laser and a recombination laser based on xenon atom transitions and generate broadband (octave) radiation in the range 2.0 – 4.2 mm with an average output power of 43 mW and an efficiency of 0.9 %. With substitution of xenon for krypton, lasing in a HF – DF – Kr laser is obtained at wavelengths of 2.52 – 4.15 mm. Lasing in a HF – DF laser was achieved simultaneously in two spectral regions (2.7 – 2.9 and 3.6 – 4.2 mm) with an output power of ~50 mW. It is found that a decrease in the pump pulse duration with a simultaneous increase in the pulse repletion rate for retaining the average energy deposition leads to an increase in the average output power and efficiency of the laser. At low pulse repetition rates (50 – 100 Hz) and a low gas mixture flow rate, helium buffer gas can be effectively substituted for neon. Operation of the Xe laser was achieved in the spectral range 2.03 – 3.65 mm with an average output power of 580 Mw at a pump pulse duration of 20 ms, a pulse repetition rate to 10 kHz, and a maximum efficiency of 55 %. The obtained experimental results demonstrate the possibility of creating broadband HF – DF – Xe lasers emitting in the frequency range 2 – 4 mm with a desired ratio of intensities in different spectral ranges.
关键词： gas discharge,spectral characteristics,planar HF – DF – Xe laser,multifrequency lasing
更新于2025-09-23 15:21:01
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A fully planar solar pumped laser based on a luminescent solar collector
摘要： A solar-pumped laser (SPL) that converts sunlight directly into a coherent and intense laser beam generally requires a large concentrating lens and precise solar tracking, thereby limiting its potential utility. Here, we demonstrate a fully-planar SPL without a lens or solar tracking. A Nd3+-doped silica fiber is coiled into a cylindrical chamber filled with a sensitizer solution, which acts as a luminescent solar collector. The body of the chamber is highly reflective while the top window is a dichroic mirror that transmits incoming sunlight and traps the fluorescence emitted by the sensitizer. The laser-oscillation threshold was reached at a natural sunlight illumination of 60% on the top window. Calculations indicated that a solar-to-laser power-conversion efficiency could eventually reach 8%. Such an SPL has potential applications in long-term renewable-energy storage or decentralised power supplies for electric vehicles and Internet-of-Things devices.
关键词： luminescent solar collector,decentralised power supplies,renewable-energy storage,fully-planar,solar-pumped laser
更新于2025-09-23 15:21:01
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Structural and Electrical Investigation of Cobalt-Doped NiOx/Perovskite Interface for Efficient Inverted Solar Cells
摘要： Inorganic hole-transporting materials (HTMs) for stable and cheap inverted perovskite-based solar cells are highly desired. In this context, NiOx, with low synthesis temperature, has been employed. However, the low conductivity and the large number of defects limit the boost of the e?ciency. An approach to improve the conductivity is metal doping. In this work, we have synthesized cobalt-doped NiOx nanoparticles containing 0.75, 1, 1.25, 2.5, and 5 mol% cobalt (Co) ions to be used for the inverted planar perovskite solar cells. The best e?ciency of the devices utilizing the low temperature-deposited Co-doped NiOx HTM obtained a champion photoconversion e?ciency of 16.42%, with 0.75 mol% of doping. Interestingly, we demonstrated that the improvement is not from an increase of the conductivity of the NiOx ?lm, but due to the improvement of the perovskite layer morphology. We observe that the Co-doping raises the interfacial recombination of the device but more importantly improves the perovskite morphology, enlarging grain size and reducing the density of bulk defects and the bulk recombination. In the case of 0.75 mol% of doping, the bene?cial e?ects do not just compensate for the deleterious one but increase performance further. Therefore, 0.75 mol% Co doping results in a signi?cant improvement in the performance of NiOx-based inverted planar perovskite solar cells, and represents a good compromise to synthesize, and deposit, the inorganic material at low temperature, without losing the performance, due to the strong impact on the structural properties of the perovskite. This work highlights the importance of the interface from two di?erent points of view, electrical and structural, recognizing the role of a low doping Co concentration, as a key to improve the inverted perovskite-based solar cells’ performance.
关键词： hole transport material,inverted planar perovskite solar cell,perovskite morphology,Co-doped NiOx,electrical conductivity
更新于2025-09-23 15:21:01