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Sobre

Sobre

Sou investigador sénior no Centro de Telecomunicações e Multimédia do INESC TEC, e coordenador da área de tecnologia ótica e eletrónica. Concluí a licenciatura em 2006 e o doutoramento em 2011, ambos em Engenharia Electrotécnica e de Computadores, pela Faculdade de Engenharia da Universidade do Porto. Atualmente sou responsável pela conceção e gestão de projetos de I&D, orientação de alunos de mestrado/doutoramento e bolseiros de investigação, e por promover a valorização de resultados de investigação através de novos contratos com a indústria. Estive envolvido como professor assistente convidado da Universidade do Porto nas disciplinas de engenharia de rádio e microondas e comunicações óticas. Sou autor/co-autor de mais de 50 publicações em conferências e revistas internacionais com revisão por pares, e de uma patente europeia. Já coordenei vários projetos de investigação e participei em vários projetos europeus. Os meus principais interesses de investigação incluem sistemas óticos coerentes, rádio-sobre-fibra, dispositivos rádio/microondas e antennas, transferência de energia sem fios e comunicações subaquáticas.

Tópicos
de interesse
Detalhes

Detalhes

022
Publicações

2023

Misalignment-Resilient Propagation Model for Underwater Optical Wireless Links

Autores
Araujo, JH; Tavares, JS; Marques, VM; Salgado, HM; Pessoa, LM;

Publicação
SENSORS

Abstract
This paper proposes a multiple-lens receiver scheme to increase the misalignment tolerance of an underwater optical wireless communications link between an autonomous underwater vehicle (AUV) and a sensor plane. An accurate model of photon propagation based on the Monte Carlo simulation is presented which accounts for the lens(es) photon refraction at the sensor interface and angular misalignment between the emitter and receiver. The results show that the ideal divergence of the beam of the emitter is around 15° for a 1 m transmission length, increasing to 22° for a shorter distance of 0.5 m but being independent of the water turbidity. In addition, it is concluded that a seven-lense scheme is approximately three times more tolerant to offset than a single lens. A random forest machine learning algorithm is also assessed for its suitability to estimate the offset and angle of the AUV in relation to the fixed sensor, based on the power distribution of each lens, in real time. The algorithm is able to estimate the offset and angular misalignment with a mean square error of 5 mm (6 mm) and 0.157 rad (0.174 rad) for a distance between the transmitter and receiver of 1 m and 0.5 m, respectively.

2023

Self-Localization via Circular Bluetooth 5.1 Antenna Array Receiver

Autores
Paulino, N; Pessoa, LM;

Publicação
IEEE ACCESS

Abstract

2022

Proof of Concept of a Low-Cost Beam-Steering Hybrid Reflectarray that Mixes Microstrip and Lens Elements Using Passive Demonstrators

Autores
Luo, Q; Gao, S; Hu, W; Liu, W; Pessoa, LM; Sobhy, M; Sun, YC;

Publicação
IEEE COMMUNICATIONS MAGAZINE

Abstract
In this article, a proof-of-concept study on the use of a hybrid design technique to reduce the number of phase shifters of a beam-scanning reflectarray (RA) is presented. An extended hemispherical lens antenna with feeds inspired by the retrodirective array is developed as a reflecting element, and the hybrid design technique mixes the lenses with the microstrip patch elements to realize a reflecting surface. Compared to the conventional designs that only use microstrip antennas to realize a reflecting surface, given a fixed aperture size the presented design uses 25 percent fewer array elements while shows comparable beam-steering performance. As a result of using fewer elements, the number of required phase shifters or other equivalent components such as RF switches and tunable materials is reduced by 25 percent, which leads to the reduction of the overall antenna system's complexity, cost, and power consumption. To verify the design concept, two passive prototypes with a center frequency at 12.5 GHz were designed and fabricated. The reflecting surface was fabricated by using standard PCB manufacturing and the lenses were fabricated using 3D printing. Good agreement between the simulation and measurement results is obtained. The presented design concept can be extended to the design of RAs operating at different frequency bands including millimetre-wave frequencies with similar radiation performances. The presented design method is not limited to the microstrip patch reflecting elements and can also be applied to the design of the hybrid RAs with different types of reflecting elements.

2022

A Gaussian Window for Interference Mitigation in Ka-band Digital Beamforming Systems

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

Publicação
2022 13th International Symposium on Communication Systems, Networks and Digital Signal Processing, CSNDSP 2022

Abstract

2022

Design and Experimental Evaluation of a Bluetooth 5.1 Antenna Array for Angle-of-Arrival Estimation

Autores
Paulino, N; Pessoa, LM; Branquinho, A; Gonçalves, E;

Publicação
13th International Symposium on Communication Systems, Networks and Digital Signal Processing, CSNDSP 2022, Porto, Portugal, July 20-22, 2022

Abstract
One the of the applications in the realm of the Internet-of-Things (IoT) is real-time localization of assets in specific application environments where satellite based global positioning is unviable. Numerous approaches for localization relying on wireless sensor mesh systems have been evaluated, but the recent Bluetooth Low Energy (BLE) 5.1 direction finding features based on Angle-of-Arrival (AoA) promise a low-cost solution for this application. In this paper, we present an implementation of a BLE 5.1 based circular antenna array, and perform two experimental evaluations over the quality of the retrieved data sampled from the array. Specifically, we retrieve samples of the phase value of the Constant Tone Extension which enables the direction finding functionalities through calculation of phase differences between antenna pairs. We evaluate the quality of the sampled phase data in an anechoic chamber, and in a real-world environment using a setup composed of four BLE beacons. © 2022 IEEE.

Teses
supervisionadas

2022

Ultra Flexible RF Electronics: Performance Study of Lines and Antennas

Autor
Rafael Perez morais

Instituição
UP-FEUP

2022

Desenvolvimento de Uma Antena em Grafeno

Autor
Luís Pedro Silva Ermida Martins de Freitas

Instituição
UP-FEUP

2022

Desenvolvimento de Uma Antena Inteligente Para 28 GHz

Autor
Margarida Granja Costa

Instituição
UP-FEUP

2021

Next Generation Long-Haul Optical Fibre Communications and Optical-Wireless Interfaces

Autor
Joana dos Santos Tavares

Instituição
UP-FEUP

2021

Vehicle Tracking in Warehouses via Bluetooth Beacon Angle-of-Arrival

Autor
Telmo Francisco da Costa Soares

Instituição
UP-FEUP