The thesis will be carried out at the Langevin Institute. The Institut Langevin is a CNRS joint research unit associated with ESPCI Paris - Université PSL, located in the 5th arrondissement of Paris, and encompassing some 100 members, including over 30 researchers and teacher-researchers. The laboratory's themes cover many aspects of wave physics, from optics to acoustics to radio frequencies.

Localization in the radio frequency (RF) domain is generally achieved by beamforming the signals recorded by an antenna array, as in MIMO systems. In such a localization system, each antenna in the array has its own RF channel, which leads to a number of disadvantages such as high costs, high energy consumption and the need for computationally intensive algorithms.
We recently presented a single-port antenna system capable of retrieving the angular position of a potential RF transmitter [1] using a compact metamaterial antenna [2], [3]. The proposed antenna has been realized by a finite periodic array of sub-wavelength (λ/6) metamaterial resonators. We show that this antenna is capable of obtaining unique angular and frequency signatures over a specific frequency band. We have demonstrated experimentally that such antennas can be used to recover the angular position in azimuth of a potential emitter by taking advantage of the signatures obtained.
Here, we propose to extend this study so as to design antennas adapted to millimeter frequencies and using narrower frequency bands. This will involve developing materials with suitable spectral characteristics for scanning both dimensions of space. Two approaches will be considered. The first involves the realization of resonant materials, and the second of traveling-wave materials. To this end, we will explore solutions based on purely metallic structures, which have significantly lower losses than meta-dielectric structures. In particular, we propose to study spoof plasmon structures, which are a two-dimensional extension of corrugated metal surfaces. These purely metallic structures enable the excitation of surface waves analogous to those generated in metasurfaces composed of coupled resonators. This work will cover several aspects: modeling spoof plasmons to maximize their dispersion while minimizing losses; understanding radiation phenomena and elaborating associated diagrams; simulations using full-wave electromagnetic tools; experimental realization and measurements; and finally, signal processing to develop high-performance localization algorithms.
[1] A. Ourir, A. Mokh, R. Khayatzadeh, M. Kamoun, A. Tourin, A. Fink, and J. de Rosny, “Angular localization of wideband sources using a single port metamaterial receive antenna,” European Conference on Antennas and Propagation, pp. 1–4, 2022. [2] A. Ourir, M. Kamoun, A. Tourin, M. Fink, and J. de Rosny, “Compact metamaterial antenna for angular localization of radio-frequency sources,” European Conference on Antennas and Propagation (EuCAP), pp. 1–5, 2023. [3] A. Ourir, M. Kammoun, T. A., F. M., and de Rosny J., “Angular localization of radio-frequency sources using a compact metamaterial receive antenna,” Progress In Electromagnetics Research M, vol. 115, pp. 163–173, 2023.