In this research, a reconfigurable metamaterial (MM) structure was designed using a millimeter-wave (MMW) band with two configurations that exhibit different refractive indices. These two MM configurations are used to guide the antenna's main beam in the desired direction in the 5th generation (5G) band of 28 GHz. The different refractive indices of the two MM configurations created phase change for the electromagnetic (EM) wave of the antenna, which deflected the main beam. A contiguous squares resonator (CSR) is proposed as an MM structure to operate at MMW band. The CSR is reconfigured using three switches to achieve two MM configurations with different refractive indices. The simulation results of the proposed antenna loaded by MM unit cells demonstrate that the radiation beam is deflected by angles of +30° and -27° in the E-plane, depending on the arrangement of the two MM configurations on the antenna substrate. Furthermore, these deflections are accompanied by gain enhancements of 1.9 dB (26.7%) and 1.5 dB (22.4%) for the positive and negative deflections, respectively. The reflection coefficients of the MM antenna are kept below -10 dB for both deflection angles at 28 GHz. The MM antennas are manufactured and measured to validate the simulated results.
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http://dx.doi.org/10.3390/ma13030582 | DOI Listing |
Sci Rep
January 2025
Department of Physics, Khalifa University of Science and Technology, 127788, Abu Dhabi, United Arab Emirates.
In this study, biopolymer composites based on chitosan (CS) with enhanced optical properties were functionalized using Manganese metal complexes and black tea solution dyes. The results indicate that CS with Mn-complexes can produce polymer hybrids with high absorption, high refractive index and controlled optical band gaps, with a significant reduction from 6.24 eV to 1.
View Article and Find Full Text PDFJ AAPOS
January 2025
Department of Ophthalmology, University of California San Francisco, San Francisco, California. Electronic address:
Purpose To determine the corneal topographic characteristics of children with blepharokeratoconjunctivitis (BKC), a chronic inflammatory ocular surface disease involving the lid margin, conjunctiva, and cornea. Methods The corneal topography of 21 children diagnosed with BKC between March 2008 and June 2019 at a single institution were reviewed retrospectively. Pachymetry and asymmetry indices were also analyzed.
View Article and Find Full Text PDFSensors (Basel)
January 2025
Department of Information Engineering, Electronics and Telecommunications (DIET), "La Sapienza" University of Rome, 00184 Rome, Italy.
This research proposes an all-metal metamaterial-based absorber with a novel geometry capable of refractive index sensing in the terahertz (THz) range. The structure consists of four concentric diamond-shaped gold resonators on the top of a gold metal plate; the resonators increase in height by 2 µm moving from the outer to the inner resonators, making the design distinctive. This novel configuration has played a very significant role in achieving multiple ultra-narrow resonant absorption peaks that produce very high sensitivity when employed as a refractive index sensor.
View Article and Find Full Text PDFBMC Ophthalmol
January 2025
Department of Ophthalmology and Visual Sciences, McGill University, 5252 Maisonneuve Blvd W, 4th floor,, Montreal, Québec, H4A 3S5, Canada.
Objective: To assess refractive and visual outcomes of a spherical Implantable Collamer Lens (ICL) followed by planned postoperative adjunctive laser-assisted in situ keratomileusis (LASIK) in the treatment of high compound hyperopic astigmatism.
Methods: In this prospective, multi-center, multi-surgeon, single-arm trial, eyes with ≥ 3.50 D hyperopia and ≥ 2.
Ann Med
December 2025
Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, China.
Objectives: The objective of the investigation is to examine the long term efficacy, safety, and predictability of ICL-V4c implantation for high and super-high myopic patients in order to provide reliable guidance for the selection of refractive surgical procedures.
Methods: We reviewed 125 eyes from 64 patients who implanted ICL-V4c at the Refractive Surgery Center of West China Hospital in Chengdu, China, between May 2015 and January 2017. These eyes were divided into two groups based on their preoperative spherical equivalent (SE) degree: high myopia (≥ -10D) and super-high myopia groups (< -10D).
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