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Publicações

Publicações por CTM

2017

Analysis of Resonant Tunnelling Diode Oscillators under Optical Modulation

Autores
Tavares, JS; Pessoa, LM; Figueiredo, JML; Salgado, HM;

Publicação
2017 19TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON)

Abstract
In this paper, we investigate the optical modulation characteristics of a resonant tunnelling diode (RTD) oscillator. This preliminary work on the first RTD-PD oscillators with an optical window available from the iBROW project demonstrate that this device can effectively be used to accomplish amplitude and frequency modulation with light injection.

2017

Nonlinear Compensation Assessment in Few-Mode Fibers via Phase-Conjugated Twin Waves

Autores
Tavares, JS; Pessoa, LM; Salgado, HM;

Publicação
JOURNAL OF LIGHTWAVE TECHNOLOGY

Abstract
In this paper, we further explore the concept of phase-conjugated twin waves (PCTW) for nonlinear cancellation in space-division multiplexed (SDM) systems. Previously, we demonstrated that the PCTW technique can successfully provide nonlinear cancellation in SDM systems. In this paper, we investigate the cases where two and four spatial modes are copropagating in a multimode fiber, considering three link lengths (1000, 3200, and 8000 km). Weak-and strong-coupling regimes are also evaluated. Our numerical simulation results show an average performance improvement > 10 dB after a 1000 km transmission link.

2017

Analysis of Loop Antenna with Ground Plane for Underwater Communications

Autores
Aboderin, O; Pessoa, LM; Salgado, HM;

Publicação
OCEANS 2017 - ABERDEEN

Abstract
Transmission and reception of high-speed short range signal is important for successful underwater water communications between an Autonomous Underwater Vehicle (AUV) or Remote Operated Vehicles (ROVs) and a docking station or underwater sensor nodes during a survey mission. The need for this form of application is currently receiving global attention from scientific groups and industries. Hence, underwater antennas are therefore required to provide these links and achieve good data rates and propagation distances for these applications either in fresh or sea water scenario. In this paper, the performance of loop antenna placed at a specified distance and parallel to the ground plane is assessed through simulation for usage in fresh water and operating in the High Frequency (HF) band. Three variations of this antenna namely; the circular loop, the square loop and the delta loop antennas has been placed on two different ground plane shapes (circular and square) for analyses of their performances. These antennas were designed in FEKO, an electromagnetic simulation software and their performance is assessed in terms of bandwidth and directivity. The results obtained shows that the antennas exhibit wideband and high directivity with square loop antenna placed on a square ground plane having slight advantages over the other antennas with respect to their bandwidth and directivity. Experimental results added for the same antenna, confirmed its performance in terms of the measured parameters are in good agreement with simulation results.

2017

Wideband Dipole Antennas with Parasitic Elements for Underwater Communications

Autores
Aboderin, O; Pessoa, LM; Salgado, HM;

Publicação
OCEANS 2017 - ABERDEEN

Abstract
Propagation of underwater electromagnetic signals for real-time transmission and reception of data gathered during a survey mission between an Autonomous Underwater Vehicle (AUV) and underwater sensor nodes or a docking station, continues to generate a lot of interest worldwide. To this end, underwater antennas will play a significant role in ensuring good data rates and propagation distances for various underwater applications. In this paper, the performance of two dipole antennas with different parasitic elements is assessed through simulation for usage in fresh water and operating in the High Frequency (HF) band. The antennas were designed in FEKO, an electromagnetic simulation software and their performance is assessed in terms of bandwidth, directivity and antenna-to-antenna distance. The results obtained show that these antennas exhibit wide bandwidth, which is important to achieve high data rates. Experimental results of the reflection coefficient of the fabricated antenna measured in fresh water are given that agree well with the simulation results.

2017

Performance evaluation of antennas for underwater applications

Autores
Aboderin, O; Pessoa, LM; Salgado, HM;

Publicação
2017 Wireless Days, WD 2017

Abstract
The capability of an Autonomous Underwater Vehicle (AUV) or Remote Operated Vehicles (ROVs) to communicate with underwater sensor nodes or a docking station, for the exchange or transfer of data gathered during a survey mission, requires an high-speed short-range communication link. This is important because of the global attention to the underwater communication applications. To this end, underwater antennas will play a significant role in ensuring good data rates and propagation distances for these applications. In this paper, the performance of three antennas, specifically, loop, dipole and J-pole is assessed through simulation for usage in fresh and sea water operating in the High Frequency (HF) band. The antennas were designed in FEKO, an electromagnetic simulation software and their performance is assessed in terms of bandwidth and directivity. The results obtained shows that the J-pole antenna has significant advantages in term of the measured parameters over the other antennas. Experimental results of the reflection coefficient of the J-pole antenna in fresh water are given that agree well with the simulation results. © 2017 IEEE.

2017

Europe and the Future for WPT COST Action IC1301 Team

Autores
Carvalho, NB; Georgiadis, A; Costanzo, A; Stevens, N; Kracek, J; Pessoa, L; Roselli, L; Dualibe, F; Schreurs, D; Mutlu, S; Rogier, H; Visser, H; Takacs, A; Rocca, P; Dimitriou, A; Michalski, J; Raida, Z; Tedjini, S; Joseph, W; Duroc, Y; Sahalos, JN; Bletsas, A; Samaras, T; Nikoletseas, S; Raptis, TP; Boaventura, A; Collado, A; Trevisan, R; Minnaert, B; Svanda, M; Pereira, M; Mongiardo, M; Popov, G; Pan, N; Aubert, H; Viani, F; Siachalou, S; Kant, P; Vera, GA; Polycarpou, AC; Cruz, P; Mastri, F; Mazanek, M; Santos, H; Alimenti, F; Garcia Vazquez, H; Pollin, S; Poli, L; Belo, D; Masotti, D; Machac, J; Tavares, V; Mezzanotte, P; Ndungidi, P; Oliveri, G; Fernandes, R; Salgado, H; Moeyaert, V; Massa, A; Goncalves, R; Pinho, P; Monti, G; Tarricone, L; Dionigi, M; Russer, P; Russer, J;

Publicação
IEEE MICROWAVE MAGAZINE

Abstract
This article presents European-based contributions for wireless power transmission (WPT), related to applications ranging from future Internet of Things (IoT) and fifth-generation (5G) systems to high-power electric vehicle charging. The contributors are all members of a European consortium on WPT, COST Action IC1301. WPT is the driving technology that will enable the next stage in the current consumer electronics revolution, including batteryless sensors, passive RF identification (RFID), passive wireless sensors, the IoT, and machine-to-machine solutions. The article discusses the latest developments in research by some of the members of this group.

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