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Generalized Hartmann-Shack array of dielectric metalens sub-arrays for polarimetric beam profiling
摘要： To define and characterize optical systems, obtaining the amplitude, phase, and polarization profile of optical beams is of utmost importance. Traditional polarimetry is well established to characterize the polarization state. Recently, metasurfaces have successfully been introduced as compact optical components. Here, we take the metasurface concept to the system level by realizing arrays of metalenses, allowing the determination of the polarization profile of an optical beam. We use silicon-based metalenses with a numerical aperture of 0.32 and a mean measured focusing efficiency in transmission mode of 28% at a wavelength of 1550 nm. Our system is extremely compact and allows for real-time beam diagnostics by inspecting the foci amplitudes. By further analyzing the foci displacements in the spirit of a Hartmann-Shack wavefront sensor, we can simultaneously detect phase-gradient profiles. As application examples, we diagnose the profiles of a radially polarized beam, an azimuthally polarized beam, and of a vortex beam.
关键词： metasurfaces,metalens,beam profiling,polarimetry,Hartmann-Shack array
更新于2025-09-23 15:21:01
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The coherent THz Smith-Purcell radiation from a three-dimensional open holes array structure
摘要： Coherent Smith-Purcell radiation from multiple electron beam excitation in a three-dimensional open holes array structure has been proposed. The electron beam passes through the holes, which can be coupled with each other to enhance surface wave fields, so that the multiple electron beam injection can interact with the surface wave field efficiently. And the Smith-Purcell radiation will be enhanced due to an increasement in dipole oscillations occurring when the electrons pass through the holes. Therefore, a high beam-wave interaction efficiency is yielded and very strong coherent terahertz radiation can be generated. This multi-beam system is expected to provide a favorable way to excite the coherent Smith-Purcell radiation, which would be used to generate terahertz radiation.
关键词： terahertz radiation,open holes array structure,Smith-Purcell radiation,electron beam
更新于2025-09-23 15:21:01
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Robust multifrequency imaging with MUSIC
摘要： In this paper, we study the MUltiple SIgnal Classification (MUSIC) algorithm often used to image small targets when multiple measurement vectors are available. We show that this algorithm may be used when the imaging problem can be cast as a linear system that admits a special factorization. We discuss several active array imaging configurations where this factorization is exact, as well as other configurations where the factorization only holds approximately and, hence, the results provided by MUSIC deteriorate. We give special attention to the most general setting where an active array with an arbitrary number of transmitters and receivers uses signals of multiple frequencies to image the targets. This setting provides all the possible diversity of information that can be obtained from the illuminations. We give a theorem that shows that MUSIC is robust with respect to additive noise provided that the targets are well separated. The theorem also shows the relevance of using appropriate sets of controlled parameters, such as excitations, to form the images with MUSIC robustly. We present numerical experiments that support our theoretical results.
关键词： multiple measurement vectors,MUSIC,array imaging
更新于2025-09-23 15:21:01
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Organic Printed Core-Shell Heterostructure Arrays: A Universal Approach to All-Color Laser Display Panels
摘要： We demonstrate a universal approach for realizing dual-wavelength lasing in organic core-shell structured microlaser arrays, which show great promise in serving as all-color laser display panels. By alternately printing hydrophilic and hydrophobic laser dye solutions on preprocessed substrates, we successfully obtained precisely patterned core-shell heterostructure arrays. The spatially-separated core and shell independently function as optical resonators to support dual-wavelength tunable microlasers in each heterostructure. Such a general method enables to flexibly control the lasing wavelength of the core-shell microlasers across a wide spectral range by systematically designing the gain media. Using as-prepared microlaser arrays as display panels, we achieved full-color laser displays, representing an achievable color gamut much larger than that of standard RGB space. These results may provide new insights for design concepts and device construction for novel optoelectronic applications.
关键词： organic heterostructure,laser display,dual-wavelength laser,core-shell structure,laser array
更新于2025-09-23 15:21:01
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[IEEE 2019 4th International Conference on Recent Trends on Electronics, Information, Communication & Technology (RTEICT) - Bangalore, India (2019.5.17-2019.5.18)] 2019 4th International Conference on Recent Trends on Electronics, Information, Communication & Technology (RTEICT) - Modeling and simulation of a Micro-grid connected with PV solar cell & its protection strategy
摘要： In the present day scenario due to change the rapid demand and over global climate change in increased the sustainable Distributed generation (DG) resources such as fuel , wind and solar. Society moving to the conventional resources like as solar, wind etc. To fill surplus demand need alternative sources like solar cell. It has a distinct concern in this scenario as it is pollution free, clean, unlimited and free. In this Paper we are design a micro-grid model by using PV cell with help of boot converter. This model is basically applicable in rural or islanded load system. Here we also discussing the operation of autonomous or grid connected microgrid model by using PV cell with help of Boost converter. PV model is completed by using MATLAB SIMULINK and different current Voltage and power levels. The MATLAB SIMULINK is done in island mode as well as grid-connected mode at the both end, grid end and load end. This study aims to understand the change of fault value Compared to healthy surgery that may serve as a cornerstone Selection of protection strategies that may work effectively both operating modes.
关键词： PV array,Distributed generation (DG),Boost converter,Relay,Voltage Source Converter (VSC),Maximum Power Point Tracking (MPPT)
更新于2025-09-23 15:21:01
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Design and measurement of a 5G mmW mobile backhaul transceiver at 28 GHz
摘要： High throughput and ultra low latency are the main requirements for fifth generation (5G) mobile broadband communications. Densely populated urban environments require utilization of previously underutilized millimeter wave frequency spectrum for higher data rates. The Ka-band, previously used in satellite applications, is of particular interest to terrestrial 5G mobile networks. New radio solutions are required for these frequencies, such as multiple wireless base stations organized in small cells and highly directional antennas to compensate for higher path loss. Wireless backhaul is predicted to be the most cost-effective and versatile solution to connect 5G base stations to the core network. Wireless backhaul enables flexible and easy installation of 5G base stations in ad hoc networks, supporting large crowd gatherings such as concerts and sports events. In this article, we present an architecture of a wireless backhaul transceiver, which operates on the 26.5–29.5-GHz band. The architecture described in this paper was implemented, and the performance of the receiver (Rx) array has been measured. We also present over-the-air antenna array measurement results using the Rx. The measurement results show that unequal Rx channel gains and antenna gains do not have a significant effect on the shape of the main lobe of the radiation pattern. We have measured a coherence gain of 2.7 dB from two Rx channels that is close to the theoretical value of 3.0 dB. We have achieved a conducted Rx EVM of better than 2% using a 100-MHz 16-QAM modulated signal at 26.5 GHz.
关键词： Antenna pattern,Beamforming,Millimeter wave,Radio frequency,Transceiver,5G,Antenna array,Backhaul
更新于2025-09-23 15:21:01
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A COMPACT CPW FED CRR LOADED FOUR ELEMENT METAMATERIAL ARRAY ANTENNA FOR WIRELESS APPLICATION
摘要： A compact coplanar waveguide (CPW) fed close ring resonator (CRR) loaded four-element metamaterial (MTM) array antenna for wireless application is designed and discussed in this article. The array is designed with corporate feeding network, arranged in a manner to offer 3 dB power at its each element. The proposed 1 × 4 MTM array antenna offers a fractional bandwidth of 10.18% with respect to the resonance frequency of fr = 2:26 GHz. At the resonance frequency of 2.26 GHz, the proposed 1 × 4 MTM array antenna offers a gain of 5.10 dBi in the direction of broadside radiation. Each element of the proposed array antenna consists of CRR, which removes the requirement of via and allows the design of a uniplanar MTM array. The overall electrical size of the single element antenna shows compactness of 0:255λ0 ×0:155λ0 ×0:012λ0, where λ0 is the free space wavelength at its resonance frequency of fr = 2:3 GHz. The proposed MTM array antenna is designed and simulated on ANSYS HFSS 14.0, and simulated results are verified with the fabricated proto-type.
关键词： wireless application,metamaterial,compact,CRR loaded,CPW fed,array antenna
更新于2025-09-23 15:21:01
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Research and Modeling of Photovoltaic Array Channel Noise Characteristics
摘要： The photovoltaic array can be used as a medium for carrier communication to realize monitoring of photovoltaic components. Photovoltaic array channel noise, especially the pulse-type noise therein, seriously interferes carrier communication, so it is necessary to grasp the characteristics of the photovoltaic array channel noise. Photovoltaic array channel noise modeling is a key process when conducting anti-noise immunity tests of monitoring equipment. Based on the time-domain waveform of photovoltaic series channel noise which is measured in a photovoltaic power station, this paper proposes a photovoltaic array noise modeling method of Wavelet Peak-Type Markov chain, and studies the in?uence on modeling accuracy when different mother wavelets are adopted for modeling. From the simulation results, root mean square errors of the predicted output for Haar, Biorthogonal and Daubechies wavelet-based function modeling case are 0.9614 V, 1.4915 V and 0.7928 V, respectively, validating that Daubechies wavelet-based function is the best wavelet-based function of modeling. In the case that the peak of original noise reaches 20 V, the predicted mean absolute error of this model is only 0.4926 V, which not only veri?es the applicability of the Wavelet Peak-Type Markov chain model to the photovoltaic array channel noise, but also veri?es the applicability to the pulse-type noise.
关键词： photovoltaic array channel noise,noise characteristics and modeling,wavelet packet decomposition and recombination,Peak-Type Markov chain
更新于2025-09-23 15:21:01
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An enhanced circular polarization near-field focused antenna array by director patches
摘要： This paper presents an enhanced circular polarization (CP) near-field focused (NFF) antenna array. There exist three advantages for the CP NFF antenna. First, this study provides an effective way to realize the CP and NFF simultaneously and do not need to design a specific patch shape for CP, which provides more freedom to change the patch shape for improving other performances. The effective way is arranging the element excitation according to maximum power transmission efficiency theory under the condition of a CP testing antenna. Second, the array element consists of a driven and director patches, and the director patches tilt the element beam from broadside direction to focal point, and then obviously enhance the electric field focusing gain. Third, the proposed array antenna achieves much less size of focal point by using much less element number than published papers. The curves for the impedance and axial ratio (AR) as function of frequency, focus width and depth are analyzed. The simulated and measured results basically agree.
关键词： antenna array,circular polarization (CP),near-field focused (NFF) antenna,director patch
更新于2025-09-23 15:21:01
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Surface-plasmon-coupled chemiluminescence amplification of silver nanoparticles modified immunosensor for high-throughput ultrasensitive detection of multiple mycotoxins
摘要： A novel surface-plasmon-coupled chemiluminescent immunosensor was developed for the detection of multiplex mycotoxins with ultrahigh sensitivity, high throughput and simplicity. The immunosensor was constructed by immobilizing carboxyl modified silver nanoparticles (AgNPs) and bovine serum albumin combined antigens sequentially on the glass chip modified with amino groups. The optical properties of AgNPs could amplify the chemiluminescence (CL) generated on the chip through the surface plasmon resonance phenomenon. Using a competitive immunoassay, the CL signals from all the sensing sites on the chip were collected simultaneously by a charge-coupled device for ultrasensitive analysis of multiple mycotoxins. Citrinin, aflatoxin B1 and ochratoxins A were selected as model analytes. Under optimal conditions, the surface-plasmon-coupled chemiluminescent immunosensor-based method presented wide linear ranges over 4 orders of magnitude and much lower limits of detection than previous work. The assay results of mycotoxins in red yeast rice samples using the proposed method were in good agreement with that using the liquid chromatography-mass spectrometry method. Its high selectivity, high throughput, acceptable stability and accuracy showed broad prospects in mycotoxin monitoring and evaluation of safety on Traditional Chinese Medicine.
关键词： Immunosensor array,Signal amplification,Silver nanoparticle,Multiplex immunoassay,Mycotoxins,Surface-plasmon-coupled chemiluminescence
更新于2025-09-23 15:21:01