Towards Autonomous Node Sensors: Green Versus RF Energy Harvesting

Several researchers are working on the development of new power methods to replace batteries. For low power embedded systems, such as sensors node (or mote), many novel technics have been investigated to create autonomous sensors that incorporate different power sources, more sustainable and ecological. The two main principal alternatives to batteries pass by harvesting power from green energy sources or Radio-frequency (RF) radiations. Energy harvesting consists of extracting electrical energy from ambient energy sources. RF energy is a different form of energy that can be found in an ambient environment or can be used for wireless power transfer. This paper will present and compare these two approaches to design autonomous node sensors, in addition to exposing the various existing solutions.