Distance-Insensitive Wireless Power Transfer and Near-Field Communication Using a Current-Controlled Loop With a Loaded Capacitance

Using a current-controlled loop with a loaded capacitance, we experimentally demonstrated distance-insensitive wireless power transfer (WPT) and near-field communication (NFC) without additional tuning network and algorithms. The proposed loop can achieve the uniform mutual inductance within the operating distance by controlling the ratio of the current flowing through the forward and reverse loops according to the loaded capacitance. By reducing the impedance mismatch within the operating distance ranging from 0 to 7 cm, the proposed loop can provide the transfer efficiency over approximately 60% for WPT and a stable channel band width for NFC operating modes. In particular, when the receiving antenna is close proximity to the transmitting antenna, the transfer efficiency of the proposed loop is up to nearly six times higher than that of conventional loop.