Creating and sharing knowledge for telecommunications

IT researchers win the IET Award for the best paper in Microwaves, Antennas & Propagation

on 15-07-2018

... Rafael Caldeirinha and Telmo Fernandes, both from IT in Leiria, Iñigo Cuiñas from the University of Vigo and David Ferreira (a former Ph.D student, now working at Blu Wireless, Lda, Bristol, England), have won the 2018 Premium Award for the Best Paper in IET Microwaves, Antennas & Propagation. The IET Premium Award, issued by the Institute of Engineering and Technology in the UK, is a highly prestigious international award that recognises the best research paper in Microwave, Antennas & Propagation during the last two years. The winning paper, entitled “Dual-band single-layer quarter ring frequency selective surface for Wi-Fi applications” was published in IET Microwaves, Antennas & Propagation, Volume 10, Issue 4, 19 March 2016.

With the widespread anticipation of the Internet of Things in the near future and the evolving of 5G communication systems, particularly in residential areas, the number of Wi-Fi connected devices may increase exponentially. As a consequence, it is likely that some ISM frequency bands will soon become highly saturated. In certain situations, it may be useful to limit the coverage of existing and emerging wireless networks to pre-defined areas, such as an individual flat or a room and, thus, inherently minimising co-channel interference from/to neighbour Wi-Fi networks.

To this extent, the authors have proposed a new frequency selective surface (FSS) design to be used in Wi-Fi shielding applications as either a band reject or band-pass dual-band single-layer filter. The proposed design consists of a combination of basic elements, that is, ring loops/slots, and is tuned at both 2.4 and 5.2 GHz Wi-Fi frequency bands. It has a relatively stable frequency response in the aforementioned Wi-Fi bands for incidence angles ranging from 0° to 45°.

Simulation and model validation through measurements demonstrate the performance of the proposed FSS design. Active variants are also proposed and briefly evaluated, which should allow for applications where an on–off switching is desired at 2.4 and 5.2 GHz Wi-Fi bands. In a more generic case, this FSS design might also be useful for other applications where the target frequency bands have a relative offset similar to the Wi-Fi bands.

On the photo, from left to right: Rafael Caldeirinha, David Ferreira, Iñigo Cuiñas and Telmo Fernandes

Expanding our field of view up to 180º

on 23-04-2018

... The project ACode180Video aims to expand the limited field of view (FoV) of humans up to 180 degrees. A modular camera setup was built to capture multiple HD images to be compressed and stitched into a single UHD panoramic resolution with 180º FoV. This setup is comprised of 9 HD cameras mounted in a semi-circular arrangement, each one connected to a low cost processor module, which in turn is linked with a central processor unit. The processing modules are responsible for partial encoding of each image while the central one completes the process.

The project investigates efficient image stitching methods to combine images from all cameras with low computational complexity. This includes finding a reduced set of common visual features, match them between adjacent view images, geometric transform and blending.

The expected results include efficient joint coding and stitching algorithms suitable for implementation on low-cost consumer-grade equipment. Hopefully contributing to the development of sophisticated, yet affordable technology for all.

Project ACode180Video was developed under the coordination of Pedro Assunção, from the Multimedia Signal Processing Group of IT in Leiria