Doctoral theses of the School of Electrical Engineering are available in the open access repository maintained by Aalto, Aaltodoc.
Public defence in Radio Science and Engineering, M.Sc.(Tech.) Albert Salmi
Public defence from the Aalto University School of Electrical Engineering, Department of Electronics and Nanoengineering
The title of the thesis: Optimization of reactively loaded antennas
Thesis defender: Albert Salmi
Opponent: Prof. Dirk Manteuffel, Leibniz University Hannover, Germany
Custos: Prof. Ville Viikari, Aalto University School of Electrical Engineering
Future sixth-generation (6G) mobile networks will require new technological advances, particularly in antenna design. Antennas used in applications such as base stations must achieve higher performance than current solutions. This doctoral thesis develops new antenna design methods that enable higher data transfer rates and improved energy efficiency for next-generation wireless communication and sensing systems.
The research focuses on reactively loaded antennas, in which reactive components, such as inductors and capacitors, are integrated into the antenna structure to control its operation. By carefully selecting these components, the antenna’s performance can be significantly improved. In particular, the work aims to shape the radiation pattern so that the antenna transmits and receives signals efficiently in desired directions.
Determining the optimal values of reactive components is a challenging mathematical problem that requires advanced optimization techniques. The thesis introduces two computational methods for this purpose and demonstrates that they enable precise control of the antenna’s radiation pattern.
In addition, the work presents a computational method for determining the fundamental performance bounds of reactively loaded antennas. These bounds enable the assessment of potential antenna performance and the evaluation of the suitability of different antenna designs for specific applications.
The thesis focuses on antenna arrays, where multiple antenna elements operate together to enable dynamic control over the radiation characteristics. In particular, the research studies sparse antenna arrays, in which the spacing between antenna elements is unconventionally large. Such configurations can produce undesired grating lobes in the radiation pattern, which degrade performance. The research demonstrates that, in reactively loaded arrays, the grating lobes can be mitigated by shaping the radiation patterns of the antenna elements.
The results provide new tools for designing high-performance antennas and support the development of future wireless communication and sensing systems.
Key words: antenna, antenna array, fundamental bound, grating lobe, optimization, reactively loaded antenna, sparse antenna array
Thesis available for public display 7 days prior to the defence at .
Contact: albert.salmi@aalto.fi
Doctoral theses of the School of Electrical Engineering
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