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.
@article{arxiv.1111.5271,
title = {Strong Coupling Optimization With Planar Spiral Resonators},
author = {Avraham Klein and Nadav Katz},
journal= {arXiv preprint arXiv:1111.5271},
year = {2011}
}