Resumo em Inglês:
Abstract Surface Plasmon Polaritons (SPPs) are evanescent surface electromagnetic waves that propagate along a dielectric-metal interface. They allow propagating modes in waveguides with dimensions smaller than the diffraction limit. By arranging slits of different widths along a metallic film, it is possible to design plasmonic lenses through phase modulation at the slits output. The distance of energy concentration, obtained by these lenses, its called focus and is of the order of one wavelength (λ). Lenses of this type allow light coming from a micrometric waveguide, such as optical fibers, for example, to be coupled to structures such as nanometric waveguides, at short distances, reducing considerably the coupling area. In this work, by using the Finite Element Method (FEM) was simulated the energy coupling between a light source and a plasmonic waveguide using plasmonic lens operating at wavelengths of 650 nm.Resumo em Inglês:
Abstract Visible-light communication (VLC) is a technique that employs light-emitting diodes (LEDs) and photodiodes to enable communication in indoor scenarios. VLC has gathered increasing attention due to its potential for data transmission across a broad unregulated spectrum (430-790 THz). One of VLC’s primary objectives is to utilize pre-existing LED infrastructures as access points. In this investigation, we assess the performance of an indoor VLC link by measuring the illumination characteristics of commercial LED luminaire. The results are utilized to design an electronic transmission and reception circuit. An analysis was conducted to identify the optimal operating point that ensures adequate lighting and reliable communication. The designed circuits exhibited a bandwidth of 50 MHz at -3 dB. Characterization of the luminaire demonstrated that a single luminaire provided the illumination (486 lx) within the recommended range at 1.6 m. For data transmission, the variable pulse position modulation (VPPM) and the orthogonal frequency-division multiplexing (OFDM) were employed in different configurations. The bit error rate (BER) results, with a threshold of ≤ 10-3, revealed that VPPM performed best at a distance of 1.9 m with a rate of 12.5 Mbps. Conversely, OFDM modulation achieved optimal performance at 1.75 m, providing a transmission rate of 30 Mbps.Resumo em Inglês:
Abstract This paper presents an eyebolt structural fault detection system, based on the analysis of multiple electromagnetic parameters through a random forest classifier trained by both measurements and high-fidelity simulated signals. The proposed methodology is completely noninvasive and does not require the disassembly of the electrical infrastructure, allowing the live-line working. The obtained results show that the proposed multi-parameter strategy achieves high accuracy and increases the system’s capability of detecting faults, improving the efficiency of the operator’s preventive maintenance routines and, consequently, increasing the reliability of the power supply and energy distribution systems.Resumo em Inglês:
Abstract This article describes the use of a low-cost softwaredefined radio applied to an Electromagnetic Compatibility (EMC) test. The proposed system is indicated for cases when an autonomous instrument is better suited, i.e., when there is no need for external signal or power connections. As a proof of concept, a metallic cavity has its shielding parameter measured, and the obtained results illustrate the kind of outputs the instrument can provide. Details concerning the hardware and software utilized are mentioned, alongside observed pitfalls and trade-offs. It is an affordable and versatile method, which can replace the traditional use of spectrum analyzers and receivers, especially in precompliance tasks.