A new technology allows devices to be used wirelessly without what major electrical component?

A technique developed by engineers at the University of Washington called “Ambient Backscatter” allows devices to function battery-free by absorbing pre-existing radio signals. Without batteries, researchers were able to get the devices to relay information to one another at data rates of 1 kbps over distances of 45 and 75 cm. Some suggest that this technology could be useful in remote sensor networks.