:

publisherThe wireless power transmission is widely studied for many kinds of application, for example, power supply for cell phone or power source of EV. The supplying power of those applications is always over mW. But it is impossible to transmit for longer distance under the index of regulation of protection from radiofrequency electromagnetic field. Then many of such applications are considered with restriction of narrow area. Then we have surveyed low power demanding application the suitable application for wireless power transmission. Sensor Network Node (The small wireless information terminal) for HEMS (Home Energy Management System) averagely consumes low power as less than 1［mW]. Then we have tried to introduce wireless power transmission into the power supplier of the small information terminal. Then we have designed many kinds of coil for wireless power transmission. At first we have designed the single loop coil less than 0.1 ［m］ using equivalent circuit and numerical method. So we have experimented and get good agreement between theoretical results and experimental results. The transmitting distance is calculated as only 50[cm]. The spiral coil, hopping coil and LS (Large and Small) coil is examined consecutively. Finally we have concluded LS can coil satisfy the specification of the Sensor Network Node for HEMS, so as the transmitting distance is over 1m