University of Washington researchers will present a paper this month on a technology called Wi-Fi backscatter, a new communication system that uses radio frequency signals as a power source.

Researchers said the communication technology holds the promise of connecting “billions” of devices to the Internet while avoiding the pesky, long-time problem with limited battery power.

Bryce Kellogg, a doctoral student in electrical engineering, said: “One of the biggest problems with connecting the next billion devices to the internet ... is the nightmare of charging or swapping batteries for all of them.”

Traditional Wi-Fi devices are “very power expensive." But Wi-Fi backscatter could “greatly reduce dependence on batteries and maybe even get rid of them and harvest energy for many devices,” he added.

The University of Washington team developed an ultra-low power tag prototype with an antenna and circuitry that can be connected to a variety of electronic devices. The tags can talk to Wi-Fi-enabled laptops or smartphones, while consuming negligible power.

Wi-Fi signals are taged and monitored moving between routers and laptops or smartphones. The tags encode data by either reflecting or not reflecting the Wi-Fi router’s signals, making a small change in the wireless signal. Wi-Fi enabled laptops and smartphones then detect these small changes and receive data from the tag.

Kellogg said one of the beauties of Wi-Fi backscatter is there isn’t much of a limit on the types of devices it could power.

“Since it is so low power we are definitely not power constrained,” he said. “The biggest constraint on size is the antenna, and Wi-Fi antennas can get very small. Your cell phone has multiple of them.”