A Switched Modular Multi-Coil Array Transmitter Pad With Coil Rectenna Sensors to Improve Lateral Misalignment Tolerance in Wireless Power Charging of Drone Systems

In this article, a Switched Modular Multi-coil Array transmitter pad integrated with coil RecTenna (SMMART) is designed to present an intelligent wireless drone charging system that improves lateral misalignment tolerance. The resultant optimized design constitutes four independent transmitter modules, wherein each includes four spatially distributed $\mathbf{2\times2}$ array coils. Therefore, the proposed design induces a maximal uniform voltage in the Rx coil region. Moreover, the optimization procedure accounts for the miniaturization of transmitter coil size without compromising the misalignment tolerance by overlapping various transmitter modules. In addition, a novel coil-based detection system for wireless chargeable drone applications is proposed to activate the desired transmitter module based on the position of the receiver coil. The detection system consists of an array of coil rectennas integrated with a switching circuit to reduce the undesired magnetic field, enhancing the link efficiency. The prototype of the charging pad is fabricated using Litz wire, and the S21-based link efficiency is measured using an experimental setup. Besides, the fabricated coil rectenna sensor array system demonstrates a real-application model of the detection system. Hence, the proposed transmitter pad improves lateral misalignment tolerance and is considered a potential wireless drone charging system design.