Sunday, June 10, 2007

Wireless Power

While I was reading the WSO2 blog feed, I stumbled upon this post. Thought of investigating further of the current status and the physics behind the $subject.

Physicists at MIT headed by Marin Soljacic have successfully demonstrated how to wirelessly illuminate an unplugged light bulb from seven feet away [1, 2]. There work is based on magnetically coupled resonance. Just like in acoustics, two objects with same resonant frequency interact with one another strongly while weakly with off-resonant objects. Their first paper on "Efficient wireless non-radiative mid-range energy transfer" describes the theory behind method. The abstract goes as follows:

We investigate whether, and to what extent, the physical phenomenon of long-lifetime resonant electromagnetic states with localized slowly-evanescent field patterns can be used to transfer energy efficiently over non-negligible distances, even in the presence of extraneous environmental objects. Via detailed theoretical and numerical analyses of typical real-world model-situations and realistic material parameters, we establish that such a non-radiative scheme can lead to “strong coupling” between two medium-range distant such states and thus could indeed be practical for efficient medium-range wireless energy transfer.

Researchers have been experimenting on this $subject for centuries. Electromagnetic radiation is one such method, but they do have their own limitations. For example, if we use radio waves, we may end up wasting a lot of energy as it spreads in all directions. We may overcome this limitation by using lasters, but the problem with lasters is that you cannot have obstacles in between the energy source and the device that you want to power.

This work is different from the wireless charging technologies based on radio, induction or resonance. Apple, Motorola, and many other companies are already into this. Companies like SplashPower, WildCharge, etc. have already come up with the technology that can charge multiple devices at once by simply placing the gadgets on a mousepad-like surface. In the future, you'll just dump your devices on a pad and in no time they get charged!

1 comment:

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