In modern communications, and especially in IoT domain with massive deployment constraints, power consumption and cost are constantly push to lower limits. In same time, sustainable solutions are recently investigate for next IoT devices generations for eco-design approach and maintenance-free aspects saving costs. To improve communication efficiency without requiring active RF transmission, RFID technics could help moving to low power communications to zero-power-signal-infrastructure added communications.
Backscatter technique seems to be a good solution in some applications to enhance low-power wireless communication systems. Backscatter transmission modulates received RF waves by reflections to the transmitter (or other receivers). By analogy, it’s like reflecting with a mirror, light from sun to a distant observer and communicate with him with a specific modulating scheme.
In this subject, the PhD student will study standard (Orange / Wifi..), architectures dedicated to backscattering communication and thanks to ongoing developpement in sub-GHz in the team, realize a tag circuit at 3.5GHz. This up-grading in frequency remains ambitious and unresolved today. Innovative solutions must be sought in order to achieve this objective. Several investigation options are promising (beamforming / antenna design, etc.) and a comparative study will have to be carried out. The aim of the thesis is to derive the building blocks specifications as well as the main architecture. These results will consist the basis of the development of a full integrated circuit for the implementation of the tag device with back scattering communication. Finally, IC measurement will be proceed to compare performances with State-of-the-Art (interoperability distance, consumption, sensitivity, etc.).

Link: http://www.leti-cea.fr/cea-tech/leti/Pages/recherche-appliquee/plateformes/Plateforme-Conception.aspx