Wireless Electricity

Nikola Tesla first introduced his discovery of wireless power transmission during the Columbian Exposition in 1893. In 1902, he built the Wardenclyffe Tower facility in Shoreham, Long Island, in hopes of proving that any device fitted with a receiver could be made to run wirelessly across the Atlantic. Because J. P. Morgan could no longer fund the project and Westinghouse wasn’t willing to fund a form of electricity they couldn’t meter, the project was cut short. Since then, we have relied on a very complicated infrastructure of power lines running across the landscape. In 2007, team members working under Professor Marin Soljacic at Massachusetts Institute of Technology discovered an important part of accomplishing a wireless future. Professor Soljacic and colleagues formed the company Witricity Corp. that will further their research and are working on a way to make the wireless technology available. So far, they found that “two resonant objects of the same resonant frequency tend to exchange energy efficiently, while interacting weakly with extraneous off-resonant objects.” This team concentrated on using two electromagnetic resonators coupled through their magnetic fields. When the distance between the two objects was much larger than the objects, the power transfer was extremely efficient because of the strongly coupled regime. Magnetic coupling is best suited for everyday functions because common materials do not interfere with a magnetic field and is safe for people. The two objects used are copper coils designed to resonate at the same frequency. Attached to the source, the sending unit sends out a non-radiative magnetic field oscillating at MHz frequencies to the receiving unit. As explained by Moffatt, an MIT undergraduate in physics, describes: “The crucial advantage of using the non-radiative field lies in the fact that most of the power not picked up by the receiving coil remains bound to the vicinity of the sending unit, instead of being radiated into the environment and lost.” However, this limits the distance and size that can effectively transmit energy. With a culture that becomes more and more wireless each day, the benefits of such a technology could dramatically alter the way we function.

Original sources:
http://www.youtube.com/watch?v=Z8r_DYmErWQ (8/25/2013)
http://www.witricity.com/pages/company.html (8/25/2013)
http://web.mit.edu/newsoffice/2007/wireless-0607.html (8/25/2013)


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