Along the road that leads to wireless electricity, or “witricity” there is an important new travel companion: a circuit developed by researchers at Duke University capable of capturing energy from sound and wifi signals with an efficiency close to that of solar cells.
It is a small device that uses 5 copper conductors and glass fiber connected in a circuit through 5 channels made with a metamaterial. The circuit 'captures' energy from the aforementioned sources, converting it into 7.3V electrical energy (to get an idea, consider that the charging cables of cell phones provide an energy of 5V).
“We work to achieve the greatest possible efficiency,” says Allen Hawkes, one of those responsible of the project. “The properties of metamaterials do not allow them to be exploited with the design of current antennas. Putting the power of metamaterials into a cell phone would allow him to stay in office simply by bringing it to an area covered by the Wifi signal, and in the future simply to an area covered by the telephone signal".
In other words, cell phones that never drain the battery.
The research is published in detail in the journal Applied Physics Letters.