Employing a novel partitioning approach for the power transfer efficiency enhancement of near-field planar WPT system

This paper presents the development of a near-field planar wireless power transfer (WPT) system utilizing a novel partitioning approach to enhance power transfer efficiency (PTE). The design process begins with the evaluation of various coil shapes based on their inductance, leading to the selection of a square coil structure. Then, the near-field WPT system was designed by coupling two identical planar coil-based resonators separated by a $25\mathrm{mm}$ range. In particular, three different WPT systems, namely, the conventional one-coil and the partitioned two- and four-coil systems, were realized, each with the same area of $50\times 50{\mathrm{mm}}^2$. Notably, the effects of key design parameters are extensively analyzed to achieve the operating frequency at practical 433 MHz for all designed WPT systems. It was demonstrated that the proposed partitioning approach resulted in a PTE increase of 3% and 6% for the two- and four-coil WPT systems, respectively. Specifically, partitioned four-coil WPT achieved a superior PTE of 79%, exhibiting the effectiveness of the proposed technique. Furthermore, the proposed partitioned four-coil WPT system design was validated through experimental measurements. Finally, its performance was evaluated under various potential misalignments that may occur in practical scenarios.