Radio Frequency Power Transmission for Self-Sustaining Miniaturized IoT Devices: Survey and Experimental Evaluation

The Internet of Things (IoT) is a promising vision to cover a wide range of applications. However, battery-operated devices at the edge of the Internet, have a limited lifetime or involve significant maintenance effort. Energy Harvesting (EH) is one of the most investigated technologies to extend the battery lifetime. Nevertheless, the further miniaturization of devices poses challenges, mainly due to the small form factor needed. In particular, harvesting energy from miniaturized transducers (i.e., millimeter-sized solar panels) is significantly more challenging. Among other EH technologies, transmitting power wirelessly is growing in popularity as it can be controlled, and it is less unpredictable than environmental sources. This work investigates different technologies to supply small size and low power smart devices for IoT applications with wireless power transmission. The paper illustrates with experimental measurements, the power acquired with a commercial radiofrequency power transmission system from Powercaset. According to this evaluation, the RF power transfer to the battery ranged from mW to μW using millimeter-sized antennas up to meters of distance. Thus the system is an effective solution for the supply of small size IoT devices.