The next step in antenna design

Carbon nanotubes represent an appealing alternative to copper for the manufacture of antennas for wireless devices, researchers say.

A team led by Amram Bengio from Rice University in the US have been experimenting with metal-free antennas, made from single-walled carbon nanotubes dissolved in acid and then smeared onto a surface. 

The nanotubes, the researchers report in a paper published in the journal Applied Physics Letters, self-align under the influence of shear force. They then hold together through van der Waals, or short-range electrostatic, forces, resulting in a range of mechanical properties better than those of copper. 

Testing revealed that the nanotube antennas were able to handle frequencies of five, 10 and 14 gigahertz every bit as well as conventional copper models.

“We were going up to frequencies that aren’t even used in Wi-Fi and Bluetooth networks today, but will be used in the upcoming 5G generation of antennas,” says Bengio.

Although the work so far, in which the substrate for the nanotubes is a glass laboratory slide, represents only proof of concept, the researchers are confident their manufacturing process is scalable and suited to industrial output.

One primary advantage of nanotube antennas, Bengio says, is that they are much lighter than their metal counterparts, which suggests they will be well suited for installation in weight-sensitive machines, such as drones and oil exploration sensors.

“There are limits because of the physics of how an electromagnetic wave propagates through space,” explains Bengio. 

“We’re not changing anything in that regard. What we are changing is the fact that the material from which all these antennas will be made is substantially lighter, stronger and more resistant to a wider variety of adverse environmental conditions than copper.”