A team of scientists from MIT is attempting
to transfer energy wirelessly with a method called evanescent
coupling. So, what does this mean for consumers?
Well, within a limited range, it could allow electronic gadgets,
such as laptops, cell phones, and PDAs to start charging themselves
as soon as their owner walks into any room. Consumers may not
have to worry about batteries dying because they forgot to charge
How it works: First, an electrical current runs through a coil
and the current is going round, this creates an electromagnetic
field that resonates outward around the coil in a low-energy
form. When a device of compatible resonating frequency is within
range, it absorbs that energy, therefore, charging itself. Finally,
the emitter reabsorbs most of the energy that is not absorbed
by the receiver.
Whenever there’s powerful energy sources, people worry
about safety,” John Pendry, professor of physics at Imperial
College, in London said in an interview with Technology Review.
According to him, either the electric or the magnetic portion
of the near-field radiation could be utilized depending on the
application. Using the electric field would pose a health risk,
and would be better employed in applications in which people
aren’t nearby, said Pendry. Using the magnetic field would
be safer and could be implemented just as easily. “I can’t
think of any reason to worry [about health concerns], but people
will,” he said.
If this were to work for small, mobile devices, couldn’t
it work on a larger scale for electrical cars in the future?
Transmitters could be placed in the roads and the electric cars
could be charging themselves as it is being driven. Evanescent
coupling might well be the solution to lessening our dependence
on fossil fuels and help curb the depletion of the earth’s
ozone layer in the near future.