Optimization of gate controlled diode in rectenna for high efficiency RF energy harvesting

Autonomous systems are important for realization of the sensor network. The RF energy harvesting is one candidate of the power source for the systems. It extracts the electric power from the electromagnetic waves which exist environmentally [1]. We have chosen the wave of the Digital Terrestrial Television (DTTV) which frequency is around 500MHz, because the covered area and the expected power will become large, compared with others, e.g. the Wi-Fi and the cellular phone [2]. Although the DTTV is chosen, the expected received power is around or below the micro watts when the covered area is intended to be enlarged. Therefore, the most important issue of the RF energy harvesting is the high efficiency rectification on such ultralow input power level [1].