Impedance Matching for Near Field Communication Applications


The number of mobile devices on the market equipped with NFC (Near Field Communication) is growing exponentially. NFC is a widespread, standardized and wireless communication technology used, for example, for mobile financial transactions or wireless data communication over short ranges of a few centimeters. Würth Elektronik eiSos (WE) offers the coil series WE-WPCC WPT/NFC, which combines wireless coils for inductive energy transmission with one NFC antenna in a compact component. To ensure optimal data communication with NFC, the NFC antenna impedance must be matched to the output of an NFC front-end. Appnote 84 describes how any NFC antenna can be matched to the output of an NFC front-end. The matching is carried out using the WE-WPCC WPT/NFC combi-coil 760308101312. The steps required for the matching are described in detail using calculations, simulations and measurements. At the end of the appnote a possibility is shown how to verify the results mathematically and by simulation and how the matching can be optimized.

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