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Recent trends in science and technology
WIRELESS POWER TRANSMISSION
Introduction to How Wirelessspower Works
Resonance and Wireless Power
The MIT wireless power project uses a curved coil and capacitive plates.
Research at MIT indicates that induction can take place a little differently if the electromagnetic fields around the coils resonate at the same frequency. The theory uses a curved coil of wire as an inductor. A capacitance plate, which can hold a charge, attaches to each end of the coil. As electricity travels through this coil, the coil begins to resonate. Its resonant frequency is a product of the inductance of the coil and the capacitance of the plates.
Long-distance Wireless Power
Whether or not it incorporates resonance, induction generally sends power over relatively short distances. But some plans for wireless power involve moving electricity over a span of miles. A few proposals even involve sending power to the Earth from space.
In the 1980s, Canada's Communications Research Centre created a small airplane that could run off power beamed from the Earth. The unmanned plane, called the Stationary High Altitude Relay Platform (SHARP), was designed as a communications relay. Rather flying from point to point, the SHARP could fly in circles two kilometers in diameter at an altitude of about 13 miles (21 kilometers). Most importantly, the aircraft could fly for months at a time.
CONCLUSION
While scientists have built working prototypes of aircraft that run on wireless power, larger-scale applications, like power stations on the moon, are still theoretical. As the Earth's population continues to grow, however, the demand for electricity could outpace the ability to produce it and move it around. Eventually, wireless power may become a necessity rather than just an interesting idea.