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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

  • Nome

    Luís Manuel Pessoa
  • Cargo

    Responsável de Área
  • Desde

    01 fevereiro 2006
024
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 degrees for a 1 m transmission length, increasing to 22 degrees 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
Future telecommunications aim to be ubiquitous and efficient, as widely deployed connectivity will allow for a variety of edge/fog based services. Challenges are numerous, e.g., spectrum overuse, energy efficiency, latency and bandwidth, battery life and computing power of edge devices. Addressing these challenges is key to compose the backbone for the future Internet-of-Things (IoT). Among IoT applications are Indoor Positioning System and indoor Real-Time-Location-Systems systems, which are needed where GPS is unviable. The Bluetooth Low Energy (BLE) 5.1 specification introduced Direction Finding to the protocol, allowing for BLE devices with antenna arrays to derive the Angle-of-Arrival (AoA) of transmissions. Well known algorithms for AoA calculation are computationally demanding, so recent works have addressed this, since the low-cost of BLE devices may provide efficient solutions for indoor localization. In this paper, we present a system topology and algorithms for self-localization where a receiver with an antenna array utilizes the AoAs from fixed battery powered beacons to self-localize, without a centralized system or wall-power infrastructure. We conduct two main experiments using a BLE receiver of our own design. Firstly, we validate the expected behaviour in an anechoic chamber, computing the AoA with an RMSE of 10.7 degrees conduct a test in an outdoor area of 12 by 12 meters using four beacons, and present pre-processing steps prior to computing the AoAs, followed by position estimations achieving a mean absolute error of 3.6 m for 21 map positions, with a minimum as low as 1.1 m.

2023

Concept paper on novel radio frequency resistive switches

Autores
Kiazadeh A.; Deuermeier J.; Carlos E.; Martins R.; Matos S.; Cardoso F.M.; Pessoa L.M.;

Publicação
ACM International Conference Proceeding Series

Abstract
For reconfigurable radios where the signals can be easily routed from one band to another band, new radio frequency switches (RF) are a fundament. The main factor driving the power consumption of the reconfigurable intelligent system (RIS) is the need for an intermediate device with static power consumption to maintain a certain surface configuration state. Since power usage scales quadratically with the RIS area, there is a relevant interest in mitigating this drawback so that this technology can be applied to everyday objects without needing such a high intrinsic power consumption. Current switch technologies such as PIN diodes, and field effect transistors (FETs) are volatile electronic devices, resulting in high static power. In addition, dynamic power dissipation related to switching event is also considerable. Regarding energy efficiency, non-volatile radio frequency resistive switch (RFRS) concept may be better alternative solution due to several advantages: smaller area, zero-hold voltage, lower actuation bias for operation, short switching time, scalability and capable to be fabricated in the backend-of-line of standard CMOS process.

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
This paper proposes the use of a Gaussian window on the array factor as an interference mitigation method, aiming to avoid the computational complexity of the MVDR algorithm at the cost of a slight performance reduction. We show that by optimizing the parameters of the Gaussian window, it is possible to effectively mitigate the interfering signal if it is received within a certain angular range from the desired signal, while being still effective beyond that range. Finally, we show that the effectiveness of this approach is maintained across the full frequency reception range of the Ka-band, and confirm its validity using 8 × 8 and 16 × 16 array sizes. © 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

Single Sideband PAM-4 Optical Transmission: design and implementation

Autor
Sérgio Miguel Carvalho Gonçalves

Instituição
UP-FEUP

2021

Constellation shaping in high-speed optical fiber communications

Autor
Tiago Gonçalves Marques da Cunha

Instituição
UP-FEUP