Integration of Near Field Communication (NFC) Antenna and Wireless Charging Coil for Portable Electronic Products

In portable electronics applications, although near-field communication (NFC) works at 13.56MHz and wireless charging (WLC) works at from 87kHz-205kHz, the efficient integration of NFC antenna coil and WLC receiver coil can reduce the volume and cost of portable electronic equipment. In this paper, a novel NFC and WLC coil integration technology is proposed based on the wide-band impedance models of the coil. The circuit model of the proposed integrated coil is developed. Based on the developed model, the technique to improve NFC inductance's effective frequency range is investigated. Furthermore, the physical meaning of the NFC inductance and its magnetic field distribution is analyzed. Finally, the proposed integrated coil is experimentally validated.