Spray-On Antenna Could Signal the Future of Wireless

Imagine adding wireless capabilities to a car, wearable device, piece of equipment, or a home appliance by just spraying on an antenna from a can.

Researchers at Drexel University have made a spray from MXene which is the basis for next-generation antennae used for thin, flexible and transparent devices. A single coat of MXene could be a simpler and economic way to add wireless data collection, transmission capabilities and other smart features to factory equipment, engines, cars, and planes, to name a few.

MXene could be a replacement for copper, which is at the core of wireless communications in devices today.

The researchers, however, found the material retained its metal conductivity in bulk, making it an effective antenna. When they sprayed MXene ink onto an object, the researchers found it performed as good as copper antennas.

To make the antenna, a water-soluble titanium carbide powder called MXene is mixed with water.

“Spraying MXene is like dropping many sheets of paper on a desk. There are many sheets of this, but they do not lose their metallic conductivity. That's a huge benefit for different applications like antenna.”

The researchers made two strips of antennas with MXene sprayed on two films. A network analyzer used to test antennas recorded wireless performance at frequency ranges from 1.5GHz to 3.5GHz. They got peak performance – a measure of data speeds and signal reach – at the same 2.4GHz frequency used by Wi-Fi and Bluetooth. MXene is made from titanium carbide with carbon atoms in a 2D form. A layer of MXene consists of three layers of titanium atoms and two layers of carbon atoms.

Antennae in today’s wireless devices are typically attached to circuits, which will still be needed for MXene. But the material is easy to deposit and can be implemented in existing fabrication plants. Moreover, just a few grams of MXene can be spread across an entire football field, which means a lower volume would be required to put antennas on devices. Modems used in the latest phones have dozens of antennas and are complex to produce.

Having this simple processing and being transparent, it opens up a new direction of antennas.

The researchers will now formally study how MXene behaves like an antenna. One research area is to understand how 2D MXene sheets based on different metal carbides interact with electromagnetic waves, how it can form the ultimate application, and its frequency range. The research could also explore areas like communications range, which important in determining if the material could be used in modems for 5G communications, a critical component in connecting factories.

To make the antenna, a water-soluble titanium carbide powder called MXene is mixed with water.