Analytical model of mutual coupling between rectangular spiral coils with lateral misalignment for wireless power applications

Rectangular spiral coils are easier to implement in wireless power transfer (WPT) applications than circular spirals. Despite this fact, research into mutual coupling between rectangular spiral coils is insufficient. In this study, a new analytical model of mutual coupling is proposed, which converts a complex multi-turn rectangular spiral coil into a single-turn rectangular coil, simplifying calculation of the self- and mutual inductances. The mutual coupling between two different arbitrarily sized rectangular spiral coils with lateral misalignment and the rectangular cross-sections can be described accurately using this model. A series of experiments is carried out, the results of which agree well with the results of calculations. Finally, the effect of the number of turns in a coil on the coupling coefficient is discussed in order to determine the recommended number of turns. This research provides an effective tool for the design of a WPT system.