131 documents found, page 1 of 14
A multifunctional cementitious composite for pavement subgrade
Roshan, Mohammad Jawed; Abedi, Mohammadmahdi; Correia, A. Gomes; Fangueiro, Raúl; Mendes, P. M.Premature failure and degradation of layers are the main problems for transportation infrastructure. Addressing these issues necessitates implementing structural health monitoring (SHM) for pavement construction layers. To this end, this research investigated the stress/strain and damage detection capabilities of a self-sensing cementitious composite developed for potential utilization in the construction of an...
Design and fabrication of terahertz antenna arrays with integrated graphene mod...
Silva, Rui; Fernandes, José; Alpuim, P.; Mendes, P. M.The Terahertz band is considered the next frontier for wireless communications, leading to unprecedent available bandwidth, enabling unforeseen end-user devices technologies, supported by the announced 6G technologies that will make use of this band, or enabling new technological solutions at the sensing or medical application level.
GNSS antenna pattern prediction and placement optimization: a prototype method ...
Cicconet, Franciele; Silva, Rui Guilherme Coelho; Mendes, P. M.An antenna’s radiation pattern is dependent on its geometrical characteristics and its antenna’s surroundings, materials, and geometries. As such, to predict the antenna’s performance in complex environments, such as that of small antennas on large vehicles, it is necessary to obtain a model that represents such a full scenario, so that the simulation may be accomplished in the process of antenna design and pla...
Terahertz array beamforming using low-voltage graphene-modulators
Silva, Rui Guilherme Coelho; Mendes, P. M.The terahertz band (0.1-10 THz) is a vastly un-used segment of the spectrum, set to be used by future 6G communications, for its super high transmission speeds. Not only that, but radiation in the below infra-red band is also finding more uses in various applications, such as sensing and medical, where THz may enable innovative solutions. However, technology for this part of the spectrum is still in its infant ...
Modeling of a compact, implantable, dual-band antenna for biomedical applications
Bahrouni, Majdi; Houzet, Gregory; Vuong, Tan Phu; Mendes, P. M.; Dinis, Hugo Daniel Costa; Silva, Rui; Trabelsi, HichemDifferent implantable antenna designs exist to establish communication with implantable devices depending on the domain of use and the implantation space. Owing to their nature and purposes, these antennas have many imposed criteria on various characteristics, such as bandwidth, multiband behavior, radiation pattern, gain, and specific absorption rate (SAR). This presents a challenge when it comes to achieving ...
Extraction of graphene’s RF impedance through thru-reflect-line calibration
Colmiais, Ivo Henrique Baltazar; Silva, Vitor; Borme, Jérôme; Alpuim, Pedro; Mendes, P. M.Graphene has unique properties that can be exploited for radiofrequency applications. Its characterization is key for the development of new graphene devices, circuits, and systems. Due to the two-dimensional nature of graphene, there are challenges in the methodology to extract relevant characteristics that are necessary for device design. In this work, the Thru-Reflect-Line (TRL) calibration was evaluated as ...
A comprehensive review on photoacoustic-based devices for biomedical applications
Barbosa, Rita Clarisse Silva; Mendes, P. M.The photoacoustic effect is an emerging technology that has sparked significant interest in the research field since an acoustic wave can be produced simply by the incidence of light on a material or tissue. This phenomenon has been extensively investigated, not only to perform photoacoustic imaging but also to develop highly miniaturized ultrasound probes that can provide biologically meaningful information. T...
A novel approach for micro-antenna fabrication on ZrO2 substrate assisted by la...
Moura, Caroline Gomes; Dinis, Hugo Daniel Costa; Carvalho, Óscar Samuel Novais; Mendes, P. M.; Nascimento, R. M.; Silva, Filipe SamuelThe use of Yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) in medicine has rapidly expanded over the past decade, driven by its advantageous properties, showing potential to overcome titanium alloy in implant fabrication. The release of metal ions and the aesthetic problems of titanium alloy implants are the main reasons for this trend. In addition to meeting expectations regarding its properties, an...
Metamaterial vivaldi antenna array for breast cancer detection
Slimi, Marwa; Jmai, Bassem; Dinis, Hugo; Gharsallah, Ali; Mendes, P. M.The objective of this work is the design and validation of a directional Vivaldi antenna to detect tumor cells’ electromagnetic waves with a frequency of around 5 GHz. The proposed antenna is 33% smaller than a traditional Vivaldi antenna due to the use of metamaterials in its design. It has an excellent return loss of 25 dB at 5 GHz and adequate radiation characteristics as its gain is 6.2 dB at 5 GHz. The uni...
2D electronics based on graphene field effect transistors: tutorial for modelli...
Jmai, Bassem; Silva, Vitor; Mendes, P. M.This paper provides modeling and simulation insights into field-effect transistors based on graphene (GFET), focusing on the devices’ architecture with regards to the position of the gate (top-gated graphene transistors, back-gated graphene transistors, and top-/back-gated graphene transistors), substrate (silicon, silicon carbide, and quartz/glass), and the graphene growth (CVD, CVD on SiC, and mechanical exfo...