Design and Development of Planar Coil Structures for Small-Size WPTs

A compact planar coil resonator-based wireless power transfer (WPT) system has been presented in this paper. The squared coil structure showed higher inductance and, hence, it was selected for the design of required resonators. The realized system has the small size of 40 × 40 mm ² . The WPT was developed on Rogers RO3003 substrate. The operating frequency of the WPT is 433 MHz which corresponds to the practical industrial, scientific medical band. The practically realized WPT demonstrated the power transfer efficiency of 76% at the transmission distance of 22 mm.