A different approach to a highly efficient wireless energy harvesting device for low-power application

This paper presents a different approach for a highly efficient Wireless Energy Harvesting (WEH) device design at 2.45 GHz for low-power density (μW/cm2) applications. Therefore, the high-efficiency rectifier was designed, in order to evaluate its harvesting performances; the rectifier was connected to a classical antenna and the energy harvesting characterization was performed. A correct model of a Schottky diode is necessary despite the nonlinear behavior. To increase the conversion efficiency an electromagnetic resonant phenomenon is proposed. To validate this method, we developed a rectifier circuit capable of recovering signals at 2.45 GHz with a high RF-DC efficiency conversion. For a low-power density of 1.3 μW/cm2, the rectifier presents a maximum conversion efficiency of 70% and when connected to an antenna of 43%.