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- 实验方案
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Measurement-Device-Independent Quantum Key Distribution over asymmetric channel and unstable channel
摘要： We show that a high key rate of Measurement-Device-Independent Quantum Key Distribution (MDIQKD) over asymmetric and unstable quantum channel can be obtained by full optimization and compensation. Employing a gradient optimization method, we make the full optimization taking both the global optimization for the 12 independent parameters and the joint constraints for statistical fluctuations. We present a loss-compensation method by monitoring the channel loss for an unstable channel. The numerical simulation shows that the method can produce high key rate for both the asymmetric channel and the unstable channel. Compared with the existing results of independent constraints, our result here improves the key rate by 1 to tens of times in typical experimental conditions.
关键词： unstable channel,asymmetric channel,Quantum Key Distribution,loss-compensation method,Measurement-Device-Independent,full optimization
更新于2025-09-04 15:30:14
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NOISE REMOVAL TECHNIQUE IN NEAR-FIELD MILLIMETER-WAVE CYLINDRICAL SCANNING IMAGING SYSTEM
摘要： The accuracy of scattering measurements in near-?eld millimeter-wave cylindrical scanning imaging system is often degraded by the contamination from additive noise and clutter. Thus, e?cient noise and clutter removal technique is necessary to achieve accuracy improvement. This paper proposes an independent component analysis denoising algorithm, which relies on the assumption of statistical independence of the sources, where high order statistical properties are used. In the algorithm, the virtual noise components are incorporated into the independent component analysis model, which expands original one-dimensional observation to virtual multi-dimensional observations. The computationally e?cient sources estimation technique is presented, based on the joint diagonalization of fourth order cumulant matrix. The high speed millimeter-wave near-?eld cylinder scanning imaging system is set up to verify the denoising results in the range pro?les, three-dimensional scatter intensity and two-dimensional projection images. Compared with three di?erent noise models, the results indicate that the denoising algorithm shows both feasibility and validity in the near-?eld millimeter-wave cylindrical scanning imaging system.
关键词： millimeter-wave,cylindrical scanning imaging system,independent component analysis,denoising algorithm
更新于2025-09-04 15:30:14
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HIGH-RESOLUTION GRID-INDEPENDENT IMAGING FOR TERAHERTZ 2-D SYNTHETIC APERTURE RADAR WITH SPATIAL UNDER-SAMPLING
摘要： For the purpose of two-dimensional (2-D) imaging in the Terahertz (THz) near field through 2-D synthetic aperture radar technology, Fourier transform (FT) is one of the most popular imaging ways. However, FT-based algorithms would encounter performance loss either when spatial sampling is under Nyquist frequency or there are off-grid scatterers in the scene of interest. Therefore, by exploiting the theory of matrix enhancement and continuous parameter estimation, we propose to use matrix enhancement and matrix pencil (MEMP) method and matched filter to deal with arbitrarily located scatterers when spatial under-sampling is adopted. Through constructing a specifically expanded matrix, the information of the scatterers involved in the small data set can be enhanced. Then, high-resolution grid-independence 2-D imaging can be achieved by the combination of MP and matched filter. Simulation results verify the effectiveness of the proposed algorithm.
关键词： Terahertz,matrix pencil,matrix enhancement,synthetic aperture radar,Fourier transform,grid-independent imaging,under-sampling
更新于2025-09-04 15:30:14
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Metallosupramolecular Photonic Elastomers with Self‐Healing Capability and Angle‐Independent Color
摘要： Photonic elastomers that can change colors like a chameleon have shown great promise in various applications. However, it still remains a challenge to produce artificial photonic elastomers with desired optical and mechanical properties. Here, the generation of metallosupramolecular polymer-based photonic elastomers with tunable mechanical strength, angle-independent structural color, and self-healing capability is reported. The photonic elastomers are prepared by incorporating isotropically arranged monodispersed SiO2 nanoparticles within a supramolecular elastomeric matrix based on metal coordination interaction between amino-terminated poly(dimethylsiloxane) and cerium trichloride. The photonic elastomers exhibit angle-independent structural colors, while Young’s modulus and elongation at break of the as-formed photonic elastomers reach 0.24 MPa and 150%, respectively. The superior elasticity of photonic elastomers enables their chameleon-skin-like mechanochromic capability. Moreover, the photonic elastomers are capable of healing scratches or cuts to ensure sustainable optical and mechanical properties, which is crucial to their applications in wearable devices, optical coating, and visualized force sensing.
关键词： elastomers,metallosupramolecular coordination,self-healing,photonic crystals,angle-independent
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - 5G Reconfigurable Antennas
摘要： Fifth generation mobile technologies demand independently tunable antennas operating simultaneously at a number of different frequency bands. The design of two, triple band independently tunable antennas printed on a mobile handset size PCB is described for 800, 1500 and 2000 MHz bands. The two antennas are printed at the top and bottom of the PCB offering diversity. The antennas operate independently of each other tuning across the three frequency bands without affecting the resonances of the other bands.
关键词： multiband antennas,frequency agility,independent frequency tuning,5G antennas
更新于2025-09-04 15:30:14
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Polarization and incident angle independent metasurface absorber for X-Band application
摘要： In the article, polarization and incident-angle independent metasurface absorber for X-band application has been proposed. Proposed absorber unit cell composed of a circular sector attached to a cross-shaped structure. The proposed absorber is symmetrical along the horizontal and vertical axis, which supports polarization angle insensitivity. Metasurface absorber shows the very good impedance matching with free space at 10.48 GHz along with 97% absorptivity. The full width at half maximum (FWHM) bandwidth is 480 MHz (10.24-10.72 GHz). In transverse electric and magnetic (TE and TM), modes the absorptivity of the proposed absorber is maintained above 90% up to 60o incidence angle. The absorber has an ultrathin thickness of 0.028λo, where λo is the wavelength of absorption peak. The absorption phenomenon is explained by normalized impedance, E-field distribution and surface current density. To analyze the metasurface properties effective permittivity, permeability and dispersion diagram has been demonstrated. The metasurface absorber has been fabricated and it shows the good accord between simulated and measured results.
关键词： X-band,polarization independent,absorber,Metasurface
更新于2025-09-04 15:30:14
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Load-Independent Wireless Power Transfer System for Multiple Loads Over a Long Distance
摘要： In this paper, a novel long-distance wireless power transfer (WPT) system using repeater coils is proposed to provide power supplies for the driver circuits in high voltage applications such as flexible alternative current transmission systems (FACTS). Different from most of the existing wireless repeater systems where the load is only connected to the last coil and the repeater coils function solely as power relays, in the proposed system, multiple loads are powered by the repeaters. The repeater coils transfer power not only to the subsequent coils but also to the loads connected to them. Dual coil design is proposed for the repeaters with which load-independent characteristics are obtained with a suitable design of coupling coefficients. As a result, the load power can be easily adjusted without affecting each other. Load current characteristics and system efficiency have been analyzed in detail. The power transfer capability of the proposed system is illustrated for different coil quality factors and coupling coefficients. An experimental setup with 10 loads has been built to validate the effectiveness of the proposed long-distance WPT system. The maximum reachable system efficiency is about 84%.
关键词： dual coil design,Wireless power transfer (WPT),constant load characteristics,current independent,long distance
更新于2025-09-04 15:30:14