UHF Near-Field Wireless Power Transfer, Application to RFID System

Wireless power transfer (WPT) was first introduced by Nicolas Tesla in 1904. Since then, numerous studies were carried out on theoretical aspects as well as on their practical uses. Recently, WPT was used in several applications such as high power transfer at low frequencies, especially for powering electrical vehicles where huge amount of power is required. On the other hand, for smart devices, the required power is much less important, but the transfer efficiency must be high. Indeed, in many applications the devices are fully passive and their power feeding is solely based on WPT methods[1].