Efficient wireless transmission of power using resonators with coupled electric fields

Since its introduction by Nikola Tesla in 1900, the concept of wireless power transmission has expanded in many directions, including high-intensity microwave beams, lasers and mutual magnetic induction. Far-field systems such as lasers, focused microwaves and large aperture RF links are well suited for traversing large (>100 m) distances but exhibit relatively low (<10%) overall system efficiencies due to beam diffraction limits, atmospheric absorption and multiple conversion losses. Near-field devices using direct or resonant magnetic induction offer higher efficiencies but only at low power levels and close distances. This paper explores the potential of using coupled electric fields between two tuned resonant transformers as a means for transmitting considerable power (>500 W) over laboratory-scale distances (5 to 20 m) with reasonable efficiency. The paper presents design concepts, circuit simulations and test results.