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Marin Soljacic says he has the answer to wireless power, at least up to 5 meters - Image courtesy MIT
The idea of wireless energy transfer has been around for a number of years, but now MIT believes it can be done inside the lab

Massachusetts Institute of Technology (MIT) researchers have created a system that is theoretically able to power electronic devices wirelessly.  Assistant Professor Marin Soljacic of the Department of Physics and Research Laboratory of Electronics, along with MIT graduate students Aristeidis Karalis and John Joannopoulos, are working on the "evanescent coupling" technology. 

The primary downfall of other power-over-air technologies is the fact that they are extremely directional or extremely dangerous.  The first roadblock in wireless power is traditionally solved by simply increasing the power and using omni-directional antennas.  This unfortunately gives rise to the second downfall; enough of an increase in power to make omni-directional useful traditionally results in so much energy trasmitted that it is no longer safe for humans to stand near the device. 

Soljacic's team attempts to solve this problem by building an antennas that create electromagnetic fields that resonate at particular frequencies and loop back into the device rather than completely emit out into the atmosphere.  When two of these antennas operating at the same frequency have resonance loops that collide, one large loop closes between the devices and high power transmission can begin over the new electromagnetic loop. 

The technology, at least in theory, should work at distances of up to five meters.  Unfortunately, the team has not yet constructed or tested the system -- even though computer simulations and theoretical calculations both suggest that it should work. 

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RE: Amazing. :D
By peternelson on 11/16/2006 6:16:17 AM , Rating: 4
I only have one thing to say:


RFID as used in passports, proximity access cards, goods tracking..... have NO onboard power source.

The power they require is sent by the reader using an induction technique.

I don't really know of applications that need remote power like this (other than say a maglev train).

I would want to minimise the amount of electromagnetic fields anywhere near my body so don't trust this guys invention. Even if you have two fields aligned with constructive interference, what if I happen to stand at that particular point?

Additionally if it uses certain frequencies, it may interfere with television, radio or other important RF transmissions.

Wireless should only be used where necessary and for things it's appropriate to. See the "negraponte switch".

Ideas for wireless usb, wireless hdmi to your tv, are just for lazy people, and more novelty than really useful.

Plus with this tech, what happens if you place more devices into the field area, does it mean less available per device so they stop working?

I'd like to know of some actual useful applications for this technology. Most things can be Li-ion battery powered (LOL not Sony), rechargeable, or carry their own nuclear reactor (submarines, satellites) or use hydrogen fuel cells.

RE: Amazing. :D
By leidegre on 11/16/2006 10:25:13 AM , Rating: 2
You are right, this is not that big of a discovery, but it's intresting.

However is see a lot of potential in portable devices. And often you forget to charge these devices, but if you have a common place where you put them, you could automatically charge them, or schedule them to charge only when needed. That could be very usueful in wireless thing keyboard and mice. They could get thier power from such a power source, and in combination with a battery be very handy.

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