WiTricity - transmitting energy without wires

The concept of WiTricity is that the energy needed to power a device can be sent without wires in a process otherwise known as magnetically coupled resonance.

Transformers have exchanged energy for years by magnetic fields in close proximity, but this takes it one more step. The principle sends energy though the air without interacting with the objects in between. Energy can be sent wirelessly by laser, but it needs a line of sight and is dangerous if something comes between.

WiTricity is based on using coupled resonant objects. Two resonant objects of the same resonant frequency tend to exchange energy efficiently, while interacting weakly with extraneous off-resonant objects. A child on a swing is a good example of this. A swing is a type of mechanical resonance, so only when the child pumps her legs at the natural frequency of the swing is she able to impart substantial energy.

Another example involves acoustic resonances: Imagine a room with 100 identical wine glasses, each filled with wine up to a different level, so they all have different resonant frequencies. If an opera singer sings a sufficiently loud single note inside the room, a glass of the corresponding frequency might accumulate sufficient energy to even explode, while not influencing the other glasses. In any system of coupled resonators there often exists a so-called "strongly coupled" regime of operation. If one ensures to operate in that regime in a given system, the energy transfer can be very efficient. mit.edu

The concept inspires new ideas of efficient energy transfer for mobile use, and the reduction of wiring that causes resistance and a loss of energy