PhD on MIMO Lens Antennas Completed


Sarmad Shaikh succesfully completed his PhD under my supervision defending the thesis “Radio Localization Based on Angle of Arrival in EM Lens Assisted Massive MIMO” on September 18, 2018. The defense committee was formed by prof.s B. Rinner, K. Witrisal, S. Weiss and A. Tonello (suoervisor).

The idea is to provide radio localization of nodes via the estimation of the angle-of-arrival (AoA) of the received signal at a given base station equipped with a massive amount of antenna elements. The use of a large number of antenna elements has a number of potential advantages: the potentiality of significantly increasing the angle-of-arrival estimation precision, the ability to better discriminate multipath propagation, and the ability of locating a large number of radio nodes in the field.
However, a high number of antenna elements significantly increases the hardware complexity and the signal processing complexity. Hardware complexity is increased because a high number of RF hardware chains that convert the RF signals to base-band (BB) needs to be deployed. Computational complexity increases because each acquired digital signal needs to be processed to obtain an estimate of the angle-of-arrival of each radio node signal.
From these considerations, the thesis proposes the usage of an electro-magnetic (EM) lens. The idea is to exploit the ability of the EM lens to focus the received signal energy from a certain direction into a small subset of antenna elements. Therefore, by focusing the received energy into a subset of elements, a first estimation of the AoA is provided, by simply detecting the antenna elements that are energized. Further improvement can be obtained by processing the signals received by the subset of antenna elements and this helps to significantly reduce the number of RF-to-BB chains.

You can read Sarmad’s story and experience at the University of Klagenfurt – Chair of Embedded Communication Systems here.

Selected Publications


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