Imadeddine BENDJEDDOU

Abstract: Wireless sensor networks (WSN) are part of our daily lives and their applications are growing, especially with the advent of the Internet of Things. The development of autonomous, adaptable and energy-efficient communicating sensor solutions is the subject of intense research. The radio communication modules (RF) between nodes (TxRx transceivers) are the most energy consuming circuits. One way to drastically reduce energy consumption is to wake up the radio receiver only when it has to be used. For this, we use a wake-up receiver (WuRx), which itself must operate in ultra-low power consumption and provide immunity to parasitic signals (to avoid unwanted awakenings of the receiver). A major issue of the wake-up receiver is simultaneously to react to the wake-up signal but also to perform the demodulation function to extract the digital information sent by the transmitter, all with an ultra-low power consumption hardware architecture. Spintronic devices offer a robust and simple solution to this challenge. Indeed, recent studies show that these spintronic devices can serve as RF-DC converters by acting as passive frequency-selective demodulators with high sensitivity at received low power. This conversion is based on a rectification effect causing the received RF signal to be mixed with the oscillation signal of the resistor (induced by the oscillation of the magnetic field), which gives rise to a DC voltage. This PhD proposes to demonstrate such wake-up spintronic receivers. This brand new concept of wake-up receiver is expected to be low cost, compact and with low power consumption, which would allow to consider a massive exploitation in sensor networks. It is an alternative to existing concepts that will improve by significant factor the consumption and the efficiency of these wake-up receiver techniques. This concept will be developed for devices operating in two frequency ranges: 0.1-1GHz and 1-10GHz, using spintronic devices with different magnetic configuration vortex and perpendicular magnetization. This PhD work will enable the acquisition of intellectual property on multi-band spintronic WuRx and a better control of spintronic technology and related rectification properties to adapt them to the needs of wireless sensor networks. It is a multidisciplinary thesis that will draw on the expertise of a CEA laboratory (INAC / Spintec for the realization and characterization of spintronic devices) and two laboratories of Grenoble Alpes University / Grenoble INP (RFIC lab for the design of RF circuits and the GIPSA-lab for the development of new radio communication techniques). The RFIC-Lab is a recognized laboratory for its activities in the design of RF integrated circuits. It will bring its expertise in the realization of prototypes and for the design of demodulators. The Gipsa-Lab is a laboratory with a strong expertise in radio communication techniques and in particular in energy efficient communication protocols. SPINTEC, project partner, is a leader in spintronics and has a great expertise in the realization of microwave spintronic devices as well as in the characterization and modeling of their dynamic properties.