A dual-mode antenna for wireless charging and Near Field Communication

A combination of the Near Field Communication (NFC) antenna and wireless charging coil for a mobile device is proposed in this paper. By integrating the single dual-mode antenna, the mobile device can provide both the NFC and wireless charging functions. The NFC multi-loop antenna transmits power in a near range by using magnetic field coupling. A capacitive matching circuit is added to achieve good coupling with a nearby NFC device at 13.56 MHz. On the other hand, the wireless charging system harvests energy in also a near range with magnetic field coupling at 100 kHz. A PCB coplanar design is employed to integrate our design into the mobile device. Simulated and measured results are presented and good performance for both NFC and wireless charging is achieved.