A Planar Distributed Multicoil Antenna to Generate 3-D Ellipsoidally Polarized H-Field for Angular Misalignment Tolerant WPT System

Abstract

This article presents 3-D polarized magnetic-field forming using a planar multicoil transmitter antenna for wireless power transfer (WPT) applications. Three orthogonal <inline-formula> <tex-math notation="LaTeX">$H$ </tex-math></inline-formula>-field components resulting in optimized 3-D ellipsoidal polarization are generated to mitigate the angular misalignment problem by the proposed antenna. The analytical optimization of the 3-D polarized <inline-formula> <tex-math notation="LaTeX">$H$ </tex-math></inline-formula>-field is presented, and its effect on induced voltage in the receiver coil is investigated. To achieve unconstrained induced voltage in the receiver independent of its angular movement, an optimized planar multicoil design is proposed for a maximum S21 between the transmitter and the receiver coil antennas. Unlike the 3-D transmitter designs available in the literature, the proposed antenna is a 2-D planar printed circuit board (PCB) design, therefore, represents a cost-effective solution and is suitable for various practical WPT applications. The analytical results of the design are verified experimentally. The result proves that the proposed antenna is able to completely mitigate the angular misalignment problem, which represents a potential planar antenna solution for orientation-insensitive WPT applications.