Strong coupling optimization with planar spiral resonators

Planar spirals offer a highly scalable geometry appropriate for wireless power transfer via strongly coupled inductive resonators. We numerically derive a set of geometric scale and material independent coupling terms, and analyze a simple model to identify design considerations for a variety of different materials. We use our model to fabricate integrated planar resonators of handheld sizes, and optimize them to achieve high-Q factors, comparable to much larger systems, and strong coupling over significant distances with approximately constant efficiency.

► Coupled planar spirals are a highly scalable design for Wireless Power Transfer. ► We numerically derive scale and material independent coupling terms. ► Optimized designs obtained from coupling terms and spiral model. ► We build high quality handheld size coupled spirals. ► Power transfer efficiency roughly constant in strong coupling regime.