Experimental RF-signal based wireless energy transmission

The distributed measurement and control systems employing wireless connectivity are commonly seen as the key enablers for many novel industry, retail and consumer applications. Even though, the fast spread of large wireless sensor networks today is obstructed by the absence of solutions, which are at the same time dependable, and can minimize both capital and operational expenditures. In this respect the devices, which are powered with the energy collected from their environment, look very attractive. Among all of them, the systems collecting the energy from a designated wireless (i.e., radio frequency (RF)) channel can often enjoy a more stable energy income, which makes them more dependable than their counterparts. Due to this reason, in the current paper we focus on and discuss the key techniques and design aspects enabling development of a real-life RF-powered wireless sensor device. Namely, we address the problems of designing an antenna and the energy harvesting circuit with feasible efficiency. In addition, we detail particular aspects related to the design of a sensor node and optimizing its computing and communication. The developed device is tested in harsh environment as a part of a fast rotating mechanical structure, showing the feasibility of the proposed solutions. The technology discussed in the paper is an important part of the upcoming 5G and IoT development and deployment.