Select your localized edition:

Close ×

More Ways to Connect

Discover one of our 28 local entrepreneurial communities »

Be the first to know as we launch in new countries and markets around the globe.

Interested in bringing MIT Technology Review to your local market?

MIT Technology ReviewMIT Technology Review - logo

 

Unsupported browser: Your browser does not meet modern web standards. See how it scores »

Engineers at North Carolina State University have created a highly efficient, flexible, and self-healing antenna using a metal alloy that’s a liquid at room temperature.

Most of the materials that go into electronic devices are brittle, inflexible, and prone to damage, including the copper used most frequently to make antennas. The new liquid-metal antenna could make it easier to send and receive data from flexible electronics. Possible uses include sensors incorporated into clothing or other textiles, pliant electronic paper, or implantable biomedical devices.

Michael Dickey, an assistant professor of chemical and biomolecular engineering at NC State, was working with a gallium-indium alloy, which is liquid at room temperature, researching how it behaves in microchannels with a view to electronics fabrication applications. Hunting for other possible uses, he hit on the idea of making a flexible antenna. In collaboration with electrical engineer Gianluca Lazzi–then at NC State, now chair of the department of electrical and computer engineering at the University of Utah–Dickey and his students used the alloy and a common flexible polymer called polydimethylsiloxane (PDMS) to make a simple dipole antenna–essentially a straight rod, like the old-fashioned “bunny ear” antennas used for analog TV.

The researchers poured liquid PDMS into a mold that left it with a single internal channel once cured. They then injected the liquid gallium-indium mixture into the channel and sealed it. “It’s all pretty straightforward,” Dickey says.

Researchers at Lazzi’s lab tested the antenna’s performance and found that they could create an electrical contact with the device simply by jabbing a wire into the liquid, eliminating the need for solder. In the lab, the antenna radiated over a broad frequency range at about 90 percent efficiency–equivalent to the efficiency of a similar antenna made of copper. “That’s the first thing we were surprised by,” says Lazzi. The antenna also remained functional while the engineers bent, twisted, and folded it in half; they even stretched it an additional 40 percent beyond its normal length. When the stress was released, the PDMS snapped back to its original shape.

When the length of the antenna is changed by stretching it, however, the device responds to different frequencies of radio waves. Stretching the device eight millimeters shifted its peak response by over 200 megahertz. Lazzi says that this could be a novel way to tune the antenna or to create a combined antenna-sensor. Embedded in machinery or in a concrete structure such as a bridge, the antenna could monitor it for strain over time.

3 comments. Share your thoughts »

Credits: North Carolina State University

Tagged: Computing, Materials, wireless, material, antenna, polymer, $100 laptop

Reprints and Permissions | Send feedback to the editor

From the Archives

Close

Introducing MIT Technology Review Insider.

Already a Magazine subscriber?

You're automatically an Insider. It's easy to activate or upgrade your account.

Activate Your Account

Become an Insider

It's the new way to subscribe. Get even more of the tech news, research, and discoveries you crave.

Sign Up

Learn More

Find out why MIT Technology Review Insider is for you and explore your options.

Show Me