- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Information Encoding with Optical Dielectric Metasurface via Independent Multichannels
摘要： Information encryption and security is a prerequisite for information technology which can be realized by optical metasurface owing to its arbitrary manipulation over the wavelength, polarization, phase and amplitude of light. So far information encoding can be implemented by the metasurface in one-dimensional (1D) mode (either wavelength or polarization) only with several combinations of independent channels. Herein, we design dielectric metasurfaces by multiplexing for information encoding in a two-dimensional (2D) mode of both wavelength and polarization. 63 combinations made out of six independent channels by two circular polarization states (RCP and LCP) and three visible wavelengths (633 nm, 532 nm and 473 nm) are experimentally demonstrated, in sharp contrast with 7 combinations by 3 independent channels in 1D mode. This 2D mode encoding strategy enhances the encryption security dramatically and paves a novel pathway for escalating the security level of information in multichannel information encryption, anti-counterfeiting, optical data storage, and information processing.
关键词： Pancharatnam-Berry phase,photon spin-dependent state,multichannel,information processing,multiwavelength,dielectric metasurface
更新于2025-09-04 15:30:14
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W-band Sparse Imaging System Using Frequency Diverse Cavity-Fed Metasurface Antennas
摘要： We experimentally demonstrate a frequency-diverse, computational imaging system at W-band frequencies utilizing an array of cavity-fed metasurface antennas. Each metasurface antenna consists of a cavity milled from aluminum stock, with an upper plate patterned with a set of radiating slots. As a function of frequency, the metasurface cavities produce a set of spatially diverse radiation patterns that probe the re?ectivity distribution of a scene. The antennas are designed to maximize the measurement diversity and hence imaging capacity of the system. The number and distribution of the radiating slots is optimized by balancing the cavity quality factor (Q) and Fourier space coverage. In the experimental realizations, the radiation patterns from each cavity-fed metasurface antenna is ?rst measured using near-?eld scanning techniques, propagated over the imaging domain, and then stored for use in the image reconstruction step. Comprehensive alignment procedure is implemented to align the measured radiation patterns with regard to the physical position of the cavities. Using a modeling platform, we ?nd excellent agreement between the simulation and experiment, indicating the validity of the calibration and alignment procedures. The scaling of the cavity-fed metasurface antenna represents a key step in the development of alternative high-frequency apertures for imaging and beam-forming applications.
关键词： Metasurface antennas,Resonant Cavity,W-Band,Millimeter waves,Frequency Diverse,Sparse Imaging
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Auckland, New Zealand (2018.8.5-2018.8.8)] 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Broadening the Bandwidth of the Electromagnetic Metamaterial Absorber
摘要： In this paper, we will first review the application of metamaterial concept to design electromagnetic wave absorber and discuss its limitation on absorption bandwidth. Then we will show several approaches to expand the working bandwidth of metamaterial absorber including the employment of multi-resonator meta-atoms, adjusting the loss in the meta-atom resonance, as well as utilizing metasurface in the Salisbury screen design. Various design examples will be discussed that verified the feasibility of these approaches.
关键词： metasurface,metamaterial,broad bandwidth,absorber
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) - On the Use of the Source Reconstruction Method for Metasurface Design
摘要： This paper aims to facilitate the macroscopic design of radiation-controlling metasurfaces with the goal of satisfying specific far-field performance criteria rather than a desired field or power patten. The source reconstruction method, a well-developed technique for antenna measurements, is modified to accept a collection of far-field performance criteria. Solving the resulting nonlinear inverse source problem results in a set of electric and magnetic currents that directly relate to tangential fields required for established metasurface design methods. The proposed technique is presented along with a preliminary example demonstrating the capabilities of the basic framework.
关键词： metasurface design,source reconstruction method (SRM),inverse problems,antenna design
更新于2025-09-04 15:30:14
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High-Gain Fabry-Perot Antennas with Wideband Low Monostatic RCS Using Phase Gradient Metasurface
摘要： The design of two high-gain Fabry-Perot (F-P) antennas with wideband low monostatic radar cross section (RCS) is presented in this paper. Firstly, a phase gradient metasurface (PGM) without lossy layer is used to realize in-band RCS reduction and high aperture efficiency simultaneously. The simulated results show that its peak gain is 19.2 dBi and a high aperture efficiency of 58.6% is achieved. By utilizing the PGM structure, the monostatic RCS is reduced from 7GHz to 11GHz and the in-band co-polarization RCS is reduced by 13.1 dB. After that, a PGM with metamaterial absorber (MA) is designed to broaden the bandwidth of RCS reduction. A prototype antenna is fabricated and measured. The peak gain of 17.9 dBi is obtained and the monostatic RCS is reduced in a wider frequency band of 7GHz to 15GHz.
关键词： radar cross section reduction (RCSR),Fabry-Perot antenna,phase gradient metasurface (PGM),high gain,in-band RCSR
更新于2025-09-04 15:30:14
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Highly Sensitive, Affordable, and Adaptable Refractive Index Sensing with Silicon‐Based Dielectric Metasurfaces
摘要： A sensing platform is presented that uses dielectric Huygens source metasurfaces to measure refractive index changes in a microfluidic channel with experimentally measured sensitivity of 323 nm RIU?1, a figure of merit (FOM) of 5.4, and a response of 8.2 (820%) change in transmittance per refractive index unit (T/RIU). Changes in the refractive index of liquids flown through the channel are measured by single-wavelength transmittance measurement, requiring only a simple light source and photodetector, significantly reducing device expense in comparison to state-of-the-art refractive index sensing technologies. A technoeconomic analysis predicts a device costing ≈$2400 that is capable of detecting refractive index changes of the order of 2*10?8. The metasurfaces utilized are low profile, scalable, and use materials and fabrication processes compatible with CMOS and other technologies making them suitable for device integration. The Huygens metasurface system, characterized by spectrally overlapping electric and magnetic dipole modes, offers a high degree of customizability. Interplay between the two resonances may be controlled via metasurface geometry, leading to tunability of device sensitivity and measurement range. Ultrahigh sensitivity of 350 nm RIU?1 with FOM of 219, corresponding to single-wavelength sensitivity of 360 RIU?1, is demonstrated computationally through use of antisymmetric resonances of a Huygens metasurface illuminated at small incidence angles.
关键词： metasurface,refractive index sensing,subwavelength structures,biosensing,nanophotonics
更新于2025-09-04 15:30:14
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Hilbert Curve-Based Metasurface to Enhance Sensitivity of Radio Frequency Coils for 7-T MRI
摘要： In this paper, we propose a compact, lightweight, and easy-to-fabricate Hilbert curve-based metasurface resonator that can effectively increase the sensitivity (radio frequency (RF) field intensity) and penetration depth of an RF coil for 7-T magnetic resonance imaging scanner. A circuit model is proposed to accurately calculate the resonance frequency of Hilbert curve resonators of different orders. A single element of a transverse electromagnetic (EM) coil was used for this paper. The increase in the field sensitivity introduced by the proposed metasurface to an RF coil was successfully demonstrated through simulations and experiments. The EM field produced by the RF coil is redistributed due to the presence of the proposed metasurface. The key feature of the proposed structure is its significant increase in the penetration depth of magnetic fields into the imaging volume. An enhancement of the magnetic field by more than four times was observed at 13.5 cm away from the coil experimentally. Flexibility for matching the coil integrated with the proposed surface is shown.
关键词： metasurface,magnetic resonance imaging (MRI),radio frequency (RF) coil,Hilbert curve
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) - A Circularly Polarized Metasurface Antenna
摘要： The concept of metasurface antennas based on electrically small resonators was recently introduced and has opened a new window into the design of high gain antennas. In the earlier work, a linearly polarized metasurface antenna was designed and fabricated. In this work, we present the design of a circularly polarized metasurface antenna. An array of 8 × 8 cross-shaped resonators was designed to operate at 3 GHz with an overall array size of 12 cm × 12 cm (1.2 (cid:540) × 12 (cid:540)). By feeding the resonators with appropriate phases, we achieved circular polarization with a high gain of approximately 12 dBi.
关键词： feed network,Antenna array,circular polarization,metasurface
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) - Dual-Band Self-Diplexed Modulated Metasurface Antennas
摘要： This paper presents a simple and effective technique to design dual-band modulated metasurface (MTS) antennas. In MTS apertures, an equivalent surface inductance supports the propagation of a transverse magnetic (TM) surface wave (SW). The SW power can be gradually radiated at one frequency by periodically modulating the surface reactance. Indeed, one can choose the period of the modulation so its interaction with the SW results in the (-1) indexed Floquet mode entering the visible region. Therefore, in order to achieve dual-band operation with a single aperture, one has to tailor a modulation able to radiate the SW power in the desired directions at both frequencies. The proposed approach consists in superimposing two modulations with different periods on the antenna aperture. One modulation produces beam #1 at frequency f1, whereas the other one generates beam #2 at frequency f2. The resulting inductive surface is then synthesized by means of sub-wavelength patches printed on a grounded dielectric slab. Moreover, it is possible to define a different position for the source of each modulation, which allows one to self-diplex the signals at f1 and f2. After providing basic design guidelines, we present numerical results for a design case consisting of an antenna with broadside pencil beams in the K and Ka bands.
关键词： leaky wave (LW),surface wave (SW),Dual-band,metasurface
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