Wireless and portable phone chargers could soon become obsolete as Duke University's Pratt School of Engineering has created a power-harvesting device that could charge a phone's battery using Wi-Fi.

With the help of Steven Cummer, professor of electrical and computer engineering, students Allen Hawkes and Alexander Katko created the device using metamaterials that can capture energy waves and convert them into electric current, capable of recharging cell phones or other small electronic device.

The device is believed to generate a voltage more powerful than that produced through USB chargers.

The team created the metamaterial array using five fibreglasses, copper energy conductors and a circuit board. The five-cell metamaterial can convert microwave signals into 7.3 volts, in comparison with 5 volts of power from USB chargers for phones and other small devices.

Researchers said that the device operates like solar panels. It is also capable of capturing microwaves from other energy sources, including satellite, sound signals or Wi-Fi signals.

With additional modifications, the device could be fitted to phones and other small electronic devices. Users can simply charge their phones by connecting it to a Wi-Fi network in locations where there are no conventional power outlets.

 "Our work demonstrates a simple and inexpensive approach to electromagnetic power harvesting," Cummer said in a statement.  "The beauty of the design is that the basic building blocks are self-contained and additive. One can simply assemble more blocks to increase the scavenged power."