Metamaterials are artificial materials with exotic properties that cannot be found in the nature. In the electromagnetic and antenna domains, these new artificial materials can allow a significant reduction in the size of the antennas, emulate the behavior of a shaped reflector, realize small and light wave absorbers, and enhance the radiation properties of feeds. In the last years, the two-dimensional version of metamaterials, called metasurfaces, has been successfully used to realize antennas. In this context, a novel procedure able to implement an arbitrary aperture field antenna using a thin metasurface illuminated by a single point source (integrated in the same substrate) has been developed at L2E in collaboration with CNES and Airbus. This approach could lead to a new class of thin and light antennas radiating a single or multiple beams at particular directions with the desired polarization. The lightness of the structure and the simplicity of the feeding network (a simple coaxial feed instead of complex microwave circuits) make these antennas very suitable for satellite applications (microwave instruments and communications) and for satcom on the move systems.
All these elements highlight the potential of this technology, but also raise a lot of fundamental questions. Some of the critical questions will be addressed in the proposed study.
The main objective of the PhD thesis is to improve the general metasurface antenna design procedure developed at L2E (by minimizing the two following mentioned undesired effects) and to extend the procedure to multiband antennas. In details:
1. Limited bandwidth: Metasurface antennas present a limited bandwidth (roughly 7%). This is due to the interaction between the surface-wave (SW) and the periodic structure.
2. Impact of the feeder on the radiation pattern: A strong hypothesis in the metasurface antenna design procedure is the availability of a perfect surface-wave launcher. Typical SW-launchers excite the desired SW but also a space-wave that affects the radiation pattern of the antenna.
3. Multiple-band antenna. The interaction between the surface wave and the metasurface depends strongly on the field polarization. This means that TM and TE waves will “see” a different metamaterial using the same printed geometry. This aspect can be used to implement double band antennas where each band is associated at a different surface wave polarization.
As applications, several antenna solutions will be studied for both nanosat and satcom on the move applications.
The PhD candidate should hold a Masters degree in Electrical Engineering, Applied Mathematics, Physics or an equivalent title. In particular, he/she should have a strong background in electromagnetic theory, mathematics, physics, and circuit analysis.
To apply, we invite you to contact the PhD/research supervisor and fill, with him/her, the co-financing part of the online application form (Reply to the offer) by April 1st, 2019.