Enhancement of electrostatic energy harvesting using self-similar capacitor patterns

Abstract

This article describes self-similar patterns for capacitors used in electrostatic energy harvesting. The fractal geometry used in this approach allows increasing the active surface of the electrodes when the overlap is small, while featuring similar active surfaces when the electrodes are far away from each other. This therefore significantly increases the capacitance variation and hence magnifies the energy harvesting abilities. In particular, this article explores Cantor-inspired fractal capacitors for electrostatic energy harvesting. It is shown that such an approach can increase the capacitance variation by a factor of two and the harvested energy by a minimum factor of four (considering a charge-constrained cycle with constant charging voltage). However, it is also demonstrated that under some configurations, an optimal fractal order appears and is tightly related to the displacement magnitude.