There always seems to be a catch whenever a news story starts off announcing some new gadget or innovation that promises to change our lives — what the first paragraph giveth, the second paragraph usually taketh away. That was certainly the way it was a while back when scientists said they had found a way to charge batteries without the need for power cords.
It was great news. Everyone hates waiting for an open electrical socket at Starbucks (where I happen to be writing this piece, chained to a receptacle). But the second paragraph in the wireless charging story said devices have to be very close to power transmitter. Like right on top of it.
Wireless charging stations exist, but all they really eliminate is the need to plug in your exhausted device. You are still leashed because your phone has to be on top of the charger, which needs to be plugged into the wall. Buzz kill.
Promise lies in metamaterials
But researchers from Duke University and Toyota have found an exotic way to transfer useful energy across several inches of air. They call it a “superlens” and they said it can reach devices that are nearly a foot away from the charger.
There is reason to expect the superlens to achieve even greater distances in the future, however. The promise lies in metamaterials, which, if powered up, can send out various kinds of electromagnetic power. This capability is apparently great for creating security-screening images that are based on the energy that bounces off people’s bodies.
But researchers at Duke and the Toyota Research Institute of North America have shown that electromagnetic energy produced by metamaterials can also recharge batteries.
One large square and a dozen small blocks
Yaroslav Urzhumov, assistant research professor of electrical and computer engineering at Duke, said the metamaterial that the team used is essentially a large square made up of dozens of small blocks. The inside and outside of the blocks are imprinted with intricate etchings made up of copper. This design enables the square to produce a cone of electromagnetic energy in a way that even experts have a hard time explaining.
The wireless charging systems available now can only send power as far as the charger is deep. If your electromagnet is an inch in diameter, it can only shoot energy an inch, maybe two. It’s simply a physical limitation of the technology, and it explains why you need to put your phone on the wireless charger base for an energy transfer to happen.
Getting today’s wireless charging technology to cut through a foot of air would require an electromagnet that’s a foot in diameter. Want to zap power across the room? Build another room.
Or add a superlens, said Urzhumov, to push the energy along.
“The true functionality that consumers want and expect from a useful wireless power system is the ability to charge a device wherever it is — not simply to charge it without a cable,” Urzhumov said.Tags: Downtime,Gadgets & Devices