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 13.56 MHz and wireless charging (WLC) works at from 87 kHz-205 kHz, the efficient integration of the NFC antenna coil and the WLC receiver coil can reduce the volume and cost of portable electronic equipment. In this article, a novel NFC and WLC coil integration technology is proposed based on the wideband 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.