Reconfigurable system for wireless power transfer (WPT) and near field communications (NFC)

In this paper, it is investigated the possibility of using near field communication (NFC), normally applied for communicating two proximity devices, to power-up external circuitry, such as low power wireless sensors, or energy scavenging devices. For this purpose, the possibility of combining both features in a single system, able to communicate with neighboring devices via NFC and to transfer power from one device to another [wireless power transfer (WPT)], has been studied. After taking considerations on antenna design, both for NFC and WPT, a reconfigurable circuitry optimized for data and energy transfer is proposed. The circuit provides optimal close proximity wireless magnetic communications, and is able to use the same device for optimal energy transfer. This feature has been implemented and demonstrated using PCB antennas, NFC reader with a mobile phone or NFC-tag and a circuitry for charging an external Io-Li battery. The results show an improvement of the energy transfer when such circuit capability is turned on.