RF Circuits and Systems Design and Technologies Enabling IoT Applications

Internet of Things (IoT) is the paradigm used nowadays to summarize what is expected form the fourth industrial revolution (Industry 4.0) that is the connectivity of a huge number of “smart” objects disseminated in dissimilar scenarios. This concept is foreseen for practically any possible application domain: from home to transportation, from industry plants to health care, and for space monitoring. Long-term and self-sustainability of these smart thinks (people, objects, tools, etc.) becomes the most relevant aspect for the implementation of such a complex vision. In this framework, my PhD activities have been concentrated. The common goal is to investigate advanced solutions for energy-aware systems and circuits cooperating to enable the IoT paradigm. In particular, I have studied, designed and experimentally demonstrated quite a few novel solutions able to overcome some of the energy limitations existing in IoT. The first project I have developed is an energy-autonomous power relay node at 2.45 GHz that is able to harvest energy from ambient-available or from dedicated RF sources and either use it for operating the node or for supplying power to other nodes. Both a hybrid and a monolithic implementation of the relay system have been implemented. Then I was dedicated to the design of a system enabling Wake-Up Radio (WuR) operation at ultra-low power. The ambitious goal of WuR radios is to reduce the communication power consumption in Wireless Sensor Networks (WSN) and IoT. With this scope in mind, I have proposed and implemented a multi-band WuR architecture. The flexibility of using frequency diversity in WuR enables a more reliable and robust communication channel. From the source side, analytical and experimental studies have been carried out to define the optimum Power Optimized Waveform (POW) excitation to push the WuR sensitivity down to power as low as -65 dBm.