Design and implementation of dual-loop NFC antenna structure

In this paper, a novel design method to reduce the size of the ferrite sheet is proposed, while maintaining equal performance in the metal structure of Near Field Communication (NFC) antenna phone. It is implemented on Dual-Loop NFC Antenna Structure (DLNAS), at the same time reduced the size of ferrite sheet compared to the conventional Single-Loop NFC antenna structure. Analysis of inductance calculation and equivalent circuit are addressed in detail. The validity of the proposed antenna structure is verified in two ways: Reader/Writer (R/W) mode and Card mode, which is called Europay, MasterCard and Visa (EMV) test. The test results show that performance of proposed NFC antenna is, at least, the same level with conventional Single-Loop even though the size of ferrite sheet is 16% smaller. Finally, it verifies that using DLNAS can downsize up to 23% size of ferrite sheet.