Performance results for the antennas, which are made from a new type of two-dimensional material called MXene, could have ramifications for mobile, wearable and connected "internet of things" technology.
The MXene antennas, which have been in development at Drexel for just over two years, are already performing nearly as well as the copper antennas found in most mobile devices on the market today, but with the benefit of being just a fraction of their thickness and weight.
"This combination of communications performance with extreme thinness, flexibility and durability sets a new standard for antenna technology," said Yury Gogotsi, PhD, Distinguished University and Bach professor of Materials Science and Engineering in Drexel's College of Engineering, who is the lead author of a paper on the MXene antennas recently published in the journal Advanced Materials. "While copper antennas have been the best in terms of performance for quite some time, their physical limitations have prevented connected and mobile technology from making the big leaps forward that many have predicted. Due to their unique set of characteristics MXene antennas could play an enabling role in the development of IoT technology."
When it comes to antennas for future devices of the future they need to be able to work well in a variety of environments outside of the circuit boards of phones and computers. According to Gogotsi, this makes MXene an appealing material for new antennas because it can be spray applied, screen printed or inkjet-printed onto just about any substrate and remains flexible without sacrificing performance.
"Generally copper antenna arrays are manufactured by etching printed circuit boards, this is a difficult process to undertake on a flexible substrate," said Meikang Han, PhD, a post-doctoral researcher at the A.J. Drexel Nanomaterials Institute who contributed to the research. "This puts MXene at a distinct advantage because it disperses in water to produce an ink, which can be sprayed or printed onto building walls or flexible substrates to create antennas."
In the paper the performance of three sets of spray-coated MXene antennas, which were between 7-14 times thinner and 15-30 times lighter than a similar copper antenna - were addressed. The antennas were tested in both lab and open environments for key performance measures of how efficiently the antenna converts power into directed waves - gain, radiation efficiency and directivity. And the testing was conducted at the three radio frequencies commonly used for telecommunication, including one in the target frequency of operation for 5G devices.
In each instance, the MXene antennas performed within 5% percent of copper antennas, with performance increasing with thickness of the antenna. The best performing MXene patch antenna, about one-seventh the thickness of standard copper antennas, was 99% as efficient as a copper antennas operating at 16.4 GHz frequency in an open environment. MXenes were also 98% as effective as their copper counterparts operating in the 5G bandwidth.
Their performance exceeded that of several other new materials being considered for antennas, including silver ink, carbon nanotubes and graphene. And these performance numbers did not waiver when the MXene antennas were subjected to as many as 5,000 bending cycles - a mark of durability that far surpasses its peer materials.
