Frontier Research Institute for Interdisciplinary Sciences
Tohoku University

“Energy harvesting” means collection of small environmental energy such as light (solar), vibration, heat, microwave energy etc., and conversion of it to electrical energy to power wireless sensors and other electric devices. The main focus of my research is “microwave energy harvesting (Rectenna)”. Since their seamless conversion between electromagnetic waves and electric power, Rectenna has the potential for the applications in small wireless sensor devices. For wireless communication of 0.5 to 10 GHz frequencies, the corresponding wavelengths are 600 to 30 mm respectively. The physical antenna size depends on (half-) wavelength, which is too large for any practical wireless sensor devices. Therefore, the miniaturization of antenna is very challenging. My approach is to miniaturize antenna size using wave length shortening with high permittivity(ε) and high permeability(μ) materials. Nano-hetero structured materials―ferromagnetic nano-particles embedded in dielectric matrix― have been investigated as one of these high-ε and high-μ materials. My current research is mostly devoted to fabricate miniaturized antenna with nano-hetero structured materials. In future, I’m going to put these antenna into practical use such as environmental monitoring and health care monitoring.