Antennas have gotten dramatically smaller over the years as our understanding of how to maximize their efficiency has improved. Your first cell phone likely had an external antenna, but the smartphone you have now doesn’t have any visible antenna — despite all of the modern communications hardware packed inside, like WiFi, Bluetooth, and NFC. But, that doesn’t mean there isn’t still room for improvement, and this new transparent, spray-on antenna material is a huge leap forward.
The material, developed by researchers at Drexel University in Philadelphia, is a solution created by dissolving MXene in water. MXene, which was also engineered at Drexel University, is a unique material composed of titanium or molybdenum bonded with carbides or nitrides. MXene made headlines a few years ago when it was discovered that it had interesting electrical properties that could make it ideal for constructing batteries. Now, the researchers have found that it could also work very well for antennas.
When MXene is dissolved in water, it creates a low-viscosity solution that can be sprayed with inexpensive, off-the-shelf airbrushes or spray bottles. When it’s sprayed onto a surface and dried, it leaves behind a thin layer of MXene just 100 nanometers thick. That’s so thin that it’s almost completely transparent, but it still functions well as an antenna. Manufacturers could quickly spray on the material to create thin, transparent, flexible antennas for IoT devices, wearables, and mobile devices. Tests show that the MXene antennas perform just as well as conventional copper antennas, but because the material is water soluble it would be ruined if it got wet again. The team is experimenting with alternatives to water in order to overcome that limitation.