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About

About

I am a senior researcher at the Centre of Telecommunications and Multimedia of INESC TEC, where I am also the coordinator of the area of Optical and Electronic Technologies. I received the “Licenciatura” degree in 2006 and PhD degree in 2011, both in Electrical and Computer Engineering from the Faculty of Engineering of the University of Porto. Currently I am responsible for the conception and management of R&D projects, coordination of research students and fostering the valorization of research results through new contracts with industry. I was previously involved in teaching of RF/microwave engineering and optical communications as an invited assistant professor at the University of Porto. I am author/co-author of more than 50 publications in international conferences and journals with peer-review, and 1 european patent. I have coordinated several research projects and participated in several EU research projects. My main research interests include coherent optical systems, radio-over-fibre, RF/microwave devices and antennas, and underwater wireless power/communications.

Interest
Topics
Details

Details

021
Publications

2022

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

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

Publication
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

Optimizing Packet Reception Rates for Low Duty-Cycle BLE Relay Nodes

Authors
Paulino, N; Pessoa, LM; Branquinho, A; Almeida, R; Ferreira, I;

Publication
IEEE SENSORS JOURNAL

Abstract
In order to achieve the full potential of the Internet-of-Things, connectivity between devices should be ubiquitous and efficient. Wireless mesh networks are a critical component to achieve this ubiquitous connectivity for a wide range of services, and are composed of terminal devices (i.e., nodes), such as sensors of various types, and wall powered gateway devices, which provide further internet connectivity (e.g., via Wi-Fi). When considering large indoor areas, such as hospitals or industrial scenarios, the mesh must cover a large area, which introduces concerns regarding range and the number of gateways needed and respective wall cabling infrastructure, including data and power. Solutions for mesh networks implemented over different wireless protocols exist, like the recent Bluetooth Low Energy (BLE) 5.1. While BLE provides lower power consumption, some wall-power infrastructure may still be required. Alternatively, if some nodes are battery powered, concerns such as lifetime and packet delivery are introduced. We evaluate a scenario where the intermediate nodes of the mesh are battery powered, using a BLE relay of our own design, which acts as a range extender by forwarding packets from end-nodes to gateways. We present the relay's design and experimentally determine the packet forwarding efficiency for several scenarios and configurations. In the best case, up to 35% of the packets transmitted by 11 end-nodes can be forwarded to a gateway by a single relay under continuous operation. A battery lifetime of 1 year can be achieved with a relay duty cycle of 20%.

2022

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

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

Publication
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

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

Publication
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.

2021

Wide Scanning Angle Millimetre Wave 1 x 4 Planar Antenna Array on InP at 300 GHz

Authors
Hussain, B; Salgado, HM; Pessoa, LM;

Publication
APPLIED SCIENCES-BASEL

Abstract
Featured Application Short-range millimetre wave communications. The design of a uniformly spaced 1 x 4 linear antenna array using epitaxial layers of benzocyclobutene over an InP substrate is demonstrated. The array elements are conjugately matched with a uni-travelling carrier photodiode at the input. The phased array is optimised to counteract mutual coupling effects by introducing metal strips with isolated ground planes for each radiating element. The proposed antenna array can provide a gain of 10 dBi with a gain variation of +/- 3 dB. The array operates over a bandwidth of 10 GHz (295-305 GHz) with a wide scanning angle of 100 degrees in the broadside.

Supervised
thesis

2021

Publicidade em plataformas de streaming de música: Efeitos na atitude e memória do consumidor

Author
Miguel Silva Ramos

Institution
UP-FEP

2021

Plataforma digital para a prevenção, monitorização e gestão inteligente da "praga mosca da azeitona"

Author
Adília Isabel Domingues da Cruz Alves

Institution

2021

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

Author
Joana dos Santos Tavares

Institution
UP-FEUP

2021

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

Author
Telmo Francisco da Costa Soares

Institution
UP-FEUP

2021

Residential Consumer Behavioural Analysis on the Participation in Demand Response Strategies

Author
Kamalanathan Ganesan

Institution
UP-FEUP