M.Sc.(Tech.) Mikko Leino will defend the thesis "Advances in Beam-Steerable and Low-Scattering Antennas for Communications and Sensing" on 23 April 2021 at 11 in Aalto University School of Electrical Engineering, Department of Electronics and Nanoengineering.
Opponent: Prof. Ashraf Uz Zaman, Chalmers University of Technology, Sweden
Supervisor: Professor Ville Viikari, Aalto University School of Electrical Engineering, Department of Electronics and Nanoengineering
The public defense will be organized via remote technology. Follow defence:https://aalto.zoom.us/j/68339893260
Zoom Quick Guide: https://www.aalto.fi/en/services/zoom-quick-guide
Thesis available at: https://aaltodoc.aalto.fi/doc_public/eonly/riiputus/
Modern communication networks like the fifth generation (5G) wireless systems enable faster data transfer and increase the network capacity. To achieve this, new operation frequencies are required and thus new antenna solutions as well. For example, 5G’s millimeter-wave network antennas are subject to many requirements, such as operation at millimeter-wave frequencies, high efficiency, and electrical beam-steering. In addition, in the most advanced visions the communication antennas are used simultaneously in monitoring and imaging the environment.
Millimeter-wave antennas are being extensively studied, and potential solutions are constantly being sought. The purpose of the research presented in this dissertation has been to respond to the arisen challenges and opportunities in the antenna design. The dissertation presents an antenna solution for base-station use that is based on phased array and capable of electrical beam-steering. The solution enables very high efficiency in the use of radiofrequency (RF) energy and the antenna manufacturing supports low-cost mass production. The practical implementations are presented for two possible 5G frequency bands. The implementations show the challenges in the design of millimeter-wave antennas, and how different diagnostic and optimization methods can be used to analyze and improve the performance of millimeter-wave phased arrays.
In addition, a frequency-diverse imaging method previously discussed in the literature is adapted in the dissertation for the first time for phased arrays. The results are promising, and the presented method has potential to be utilized for real-time imaging in future communication networks.
Finally, with the new communication networks, the number of antennas around us will increase. Because the volume reserved for antennas is often limited, it is important to develop antenna solutions that are electrically transparent outside their operation frequency and thus do not interfere with the operation of adjacent antennas. The dissertation presents the design principles for such an antenna that is transparent outside its operation frequency as well as a functional implementation of the said antenna. This implementation is primarily designed to be used in aircraft radar system, but the design principles are widely applicable, for example, to the antennas in communication networks.
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