Focused Microwaves Could Enable Wireless Power Transfer

esocid alerts us to news out of the University of Michigan, where physics researchers have found a way to focus microwaves to a point 20 times smaller than their wavelength using a new 'superlens'. Such resolution was thought to be impossible until recent years, and it could bring about the capability to transfer power wirelessly. "No matter how powerful a conventional lens, it cannot focus light down to more than about half its wavelength, the 'diffraction limit'. This limits the amount of data that can be stored on a CD, and the size of features on computer chips. The new lens is a 127-micrometer-thick plate of teflon and ceramic with a copper topping. 'The beauty of these is that they're planar,' Grbic says, 'they're easy to fabricate.' The lenses can be made through a single step of photolithography, the process used to etch computer chips."

Comments

Re:We tried that

[Kuukai]

I know what you mean, messing with wireless power is a seriously bad idea. Tesla tried it too, and look what happened to him. He's DEAD!

Superlens = spillover = irradiation

[G4from128k]

What I remember from studying this technology 15 years ago was that it was possible to create a beam sharper than the diffraction limit, but the result was diffuse spill-over. That is, one could create an extremely sharp main lobe in the beam pattern, but one had to suffer higher side-lobes. That's OK for imaging and lithography applications -- the spill-over is diffuse enough not to cause too many problems. But for power applications it means both inefficiency (power lost to the side lobes) and irradiation for people who think they aren't in the beam.

Actually it was a very GOOD idea but NASA blew it.

[Ungrounded Lightning]

Back in the 1960's. Diode grid to rectify the beamed power. Bad idea.

Actually it was a very GOOD idea. But NASA blew it.

The plan was to site solar power satellites in geosync orbit and bring the power back via microwaves.

Unlike microwave ovens (which are tuned to a frequency that is strongly absorbed by water), these would be tuned to a frequency where water - clouds, rain, birds, cows, people - is essentially transparent. This is good both for getting the power through the atmosphere and avoiding rains of roast duck.

I could go into detail on why there's no problem from the millimeter waves, but that would take time. Short form: System failures defocus the beam so much it becomes just radio interference in directional antennas pointed at the satellites. Even when fully focussed it's not an issue for tissue: You can grow crops and graze cattle under the (rather spindly) rectennas, so they don't even use up the chunk of land they're on.

Benefits:
  - Enough power to completely replace fossil fuel AND nuclear plants and absorb forseeable energy use expansion for decades.
  - 'Way cheaper, too. (Even at '60s fuel prices.)
  - Essentially no pollution at ground level.
  - Bootstraps a space program that can then move other manufacturing processes, and THEIR pollution, off the planet as well.

NASA blew it by doing a study that purported to show it would be too expensive. But they did that by splitting the design teams for the rockets and the power plant. The power plant designers made a turbine very large to get a couple extra percent of efficiency. Then the rocket designers came up with a heavy lifter sized to take the biggest piece. Result: Enormous rockets with few trips to ammortize the design/construction costs, rather than moderate sized ones with many trips. Cost skyrockets versus a properly integrated design with a small turbine and a fleet of smaller lifters.