Two-dimensional antenna converts Wi-Fi signals into electricity

[Judi Lynn]

Michael Irving
3 hours ago

Wireless charging is increasingly common in phones and other devices, but it's still held back by a very short range – usually the device needs to sit on top of a charging pad, which cancels out some of the benefits of going wireless. In a new step towards truly wireless charging, engineers have developed an ultra-thin device that captures Wi-Fi signals and converts them into electricity.

The new system is based on existing devices called rectifying antennas, or rectennas. These capture AC electromagnetic waves in the air – such as Wi-Fi signals – and convert them into DC electricity. But most of them are rigid and, being made with silicon or gallium arsenide, are best suited to powering small electronics. So the team on the new study set out to develop a new rectenna that's flexible enough to be scaled up to much larger sizes.

For the new design, the team made the rectifier – the component that converts the current – out of molybdenum disulfide (MoS2). This semiconducting material measures just three atoms thick, making it extremely flexible while still holding its own in the efficiency department. The team says the MoS2 rectifier can capture and convert up to 10 GHz of wireless signals with an efficiency of about 30 percent. That's much higher than other flexible designs, and the researchers also say it's faster.

That said, it doesn't quite stack up against other rectifiers, which can reach efficiencies of up to 60 percent. It's also generating a relatively small amount of electricity, producing about 40 microwatts from about 150 microwatts of Wi-Fi power. Although that isn't much, it should be enough to power small wearable or medical electronic devices, removing the need for batteries.

More:
https://newatlas.com/2d-material-power-wifi-signals/58238/

[LastLiberal in PalmSprings]

1. Nikola Tesla would be pleased.

Nikola Tesla and his work in wireless energy and power transfer discusses his work on this process.

[MineralMan]

2. Back in 1957, I built a transistor amplified

crystal radio that was powered by the signal from a nearby radio station. It had one coil and variable capacitor for receiving radio broadcasts and another coil and capacitor pair, with a different diode that produced DC power to operate the transistor as an amplifier so I could drive a small loudspeaker. It worked great.

People have been pulling small amounts of electrical power from broadcast signals for a very, very long time. This might be more efficient, but the principle has been in use long before now.

Of course, the radio required a longwire antenna, as well, but that wasn't a problem.

I was just 12 years old at the time. My project won first prize in the science fair, and surprised a lot of adults, who didn't think it was possible. Ha!