New metamaterial facilitates wireless power

Posted by Emma Woollacott

Electrical engineers at Duke University say certain unique man-made materials should improve wireless power transfer dramatically, allowing laptops, cell phones, or even cars to be charged without cables.

They've been studying a metamaterial which resembles a miniature set of tan Venetian blinds. Situated between the energy source and the recipient device, it could greatly refocus the energy transmitted and allow the energy to travel with minimal loss of power.

"We currently have the ability to transmit small amounts of power over short distances, such as in radio frequency identification (RFID) devices. However, larger amounts of energy, such as that seen in lasers or microwaves, would burn up anything in its path," says Yaroslav Urzhumov, assistant research professor in electrical and computer engineering.

"Based on our calculations, it should be possible to use these novel metamaterials to increase the amount of power transmitted without the negative effects."

The research is built on the concept of so-called 'superlenses'. Traditional lenses get their focusing power by controlling rays as they pass through the two outside surfaces of the lens. On the other hand, the superlens, which is in fact a metamaterial, directs waves within the bulk of the lens between the outside surfaces, giving researchers a much greater control over whatever passes through it.

The metamaterial used in wireless power transmission would be made of hundreds or thousands of individual thin conducting loops arranged into an array. Each piece is made from the same copper-on-fiberglass substrate used in printed circuit boards, with excess copper etched away. These pieces can then be arranged in an almost infinite variety of configurations.

"The system would need to be tailored to the specific recipient device, in essence the source and target would need to be 'tuned' to each other," says Urzhumov. "This new understanding of how matematerials can be fabricated and arranged should help make the design of wireless power transmission systems more focused."