The relay effect on wireless power transfer using witricity

Witricity is a recent technology for wireless power transfer over a limited distance. In this paper, we investigate a relay effect to extend the distance. The concept of magnetic resonance in strongly coupled regime with more than two resonators is presented. Theoretical analysis is performed based on a set of differential equations and experiments are conducted to demonstrate its effectiveness. Our results show that the efficiency of power transfer can be improved significantly using one or more relay resonators. This approach enhances the performance of the present two-resonator witricity systems and allows transmitting power over a longer range, following a curved path, and using smaller resonators.