PhD defence by Carla Di Paola
18.02.2021 kl. 12.30 - 16.00
"MIMO and mm-wave Antenna Systems for 5G Mobile Terminals"
Over the past thirty years, the mobile communication has evolved from the first generation (1G) analogue systems, intended to offer only voice service, to the next generations digital systems, developed to support the increasing demand for high-throughput data transfer. Nowadays, the large number of services provided by mobile phones requires to select the millimeter-wave (mm-wave) frequency range for the upcoming fifth generation mobile communication system (5G), in order to provide wider bandwidths, that support higher capacity and massive device connectivity. However, the propagation environment becomes hostile at higher frequencies, due to larger path loss and shadowing, so higher gain antenna arrays able to achieve wide beam steering range are proposed to be embedded in mobile terminals.
In the thesis, mm-wave antenna arrays, realizing beam forming with different technologies, are presented and advantages and drawbacks are discussed. A cavity backed patch antenna array with multi-band performance is first proposed and the angle of +/-30 deg is achieved, generating various beams with different phase shifts.
Nevertheless, phased antenna arrays are affected by bandwidth limitations due to the phase shifters. To this end, a new antenna array architecture is presented, where the beamstreering is realized by switching to the feeding of one high gain array element. The switchable antenna system allows to reach a coverage range wider than +/-90 deg. On the other hand, it suffers from a larger setup and dips in the envelope, given by the discrete beams.
In order to exploit the advantages of phased and switchable antenna arrays and to cope with the drawbacks, a hybrid array is implemented. Characterized by simple structure, it allows to achieve high gain over a omnidirectional coverage, by switching between different phased arrays.
Besides the mm-wave frequency bands, the 600 MHz spectrum has been considered for 5G mobile communication in USA. However, implementing handset antennas in low band represents a challenge for antenna engineers, due to the trade-off between size, bandwidth and efficiency. In the thesis, a frequency-reconfigurable antenna system is proposed with the aim of addressing the 600 MHz band by tuning, allowing thus to keep a low profile and guarantee high performance in terms of bandwidth and total efficiency.
Professor Klaus Ingemann Pedersen, Aalborg University (chairman)
Professor Dirk Manteuffel, University of Hannover
Dr. Marta Martínez Vázquez, IMST GmbH
Professor Gert Frølund Pedersen, Aalborg University
Associate Professor Shuai Zhang, Aalborg University
Associate Professor Ole Kiel Jensen, Aalborg University
Please send an e-mail no later than Wednesday 17 February, 12:00 to email@example.com if you wish to participate.
Antennas, Propagation and Millimetre-Wave Systems, Department of Electronic Systems
Online via Microsoft Teams (link will be sent to registered participants prior to the defence)
17.02.2021 kl. 12.00