Tuesday 20 March 2018

Mobile World Congress 2018: The Tangled Fate of Graphene and 5G

These two technologies have long been hyped, and proponents of each are finally starting to work together 

                                                                    By Dexter Johnson

Graphene has been heralded as a “wonder material” for well over a decade now, and 5G has been marketed as the next big thing for at least the past five years. Analysts have suggested that 5G could be the golden ticket to virtual reality and artificial intelligence, and promised that graphene could improve technologies within electronics and optoelectronics.
But proponents of both graphene and 5G have also been accused of stirring up hype. There now seems to be a rising sense within industry circles that these glowing technological prospects will not come anytime soon.
At Mobile World Congress (MWC) in Barcelona last month, some misgivings for these long-promised technologies may have been put to rest, though, thanks in large part to each other. For the third year in a row, MWC hosted The Graphene Pavilion organized by The Graphene Flagship, the EU’s €1 billion, 10-year plan to make Europe the “Silicon Valley” of graphene.
In a meeting at MWC with Jari Kinaret, a professor at Chalmers University in Sweden and director of the Graphene Flagship, I took a guided tour around the Pavilion to see some of the technologies poised to have an impact on the development of 5G.
Being invited back to the MWC for three years is a pretty clear indication of how important graphene is to those who are trying to raise the fortunes of 5G. But just how important became more obvious to me in an interview with Frank Koppens, the leader of the quantum nano-optoelectronic group at Institute of Photonic Sciences (ICFO) just outside of Barcelona, last year.
He said: “5G cannot just scale. Some new technology is needed. And that’s why we have several companies in the Graphene Flagship that are putting a lot of pressure on us to address this issue.”
During Kinaret’s tour of the Pavilion last month, I met one research group that this blog covered in November 2017, when Chalmers researchers used graphene to combine flexibility and terahertz detection to make it possible to connect the Internet of Things via high-bandwidth 5G technologies.
In addition to this research, Kinaret also introduced me to three other research groups centered around data communications for future 5G networks. What struck me about all three of these was how much industry was involved in their realization.
Graphene-based ICs for flexible receivers/transmitters
In one such collaboration, RWTH Aachen University in Germany and AMO GmbH, a German company involved in nanofabrication technologies, had developed a way to create microwave links using integrated circuits (ICs) based on graphene.
“This flexible graphene microwave communication device has both a graphene receiver and transmitter that can be used in Wi-Fi applications as well as in millimeter wave (mmWave) technologies, which is the future of 5G,” said Ahmed Hamed Ghareeb, a researcher with RWTH Aachen.
Ghareeb said that the mobile companies at MWC were interested in using the technology to replace some parts of their base stations. “Especially in the backhaul of the wireless communication, they need some high-frequency components, which are now designed using gallium arsenide technology, which is an expensive technology,” he said. “We can make it at a lower cost and in mass production, because it’s just a printed technology.”
With the graphene-based device exhibiting comparable—and sometimes superior—performance characteristics to gallium arsenide but at a lower cost, what’s the hold up?
“I think one of the key issues at this point is yield,” explained Kinaret. “You need to be able to make not only 10 of these devices, but you need to make 10 million of these devices at 95 percent to 98 percent yield.”
To achieve this, Kinaret believes that several parts of the value chain need to be strengthened, such as material supply, in order to have consistent material quality. “We think now the variability is still a bit high,” he said. “For it to be commercially interesting, you need to have multiple suppliers. Otherwise, the companies don’t dare take the risk.”
Cryogenic cooling with no moving parts
In another industrial collaboration, researchers from Chalmers University teamed up with Sweden-based APR Technologies, a producer of thermal solutions for satellites, to create a cryogenic cooling device based on graphene.
In this research, the group has developed a miniaturized cooling pump that is both highly efficient and needs no moving parts. The technology has obvious applications for APR in keeping satellites cool. But it would also be ideal for 5G base stations, according to Peter Nilsson, the CEO of APR technologies.
The cooling pump is based on what’s called a Knudsen compressor that exploits temperature differences in the pump instead of using moving parts to compress the gas. “By having alternating patches of graphene at various temperatures—hot and cold and hot and cold—we can then compress the gas without any moving parts,” said Nilsson.
Once the compressed gas is released, it creates very low temperatures. This very low-temperature gas is then fed back into the compressor to create the cooling effect.
“It could be used for 5G base stations to cool down receivers because they have to be kept very cool to get a clear signal,” said Nilsson.
Graphene photonics for the 5G backbone
In a collaboration led by CNIT—a consortium of Italian universities and national laboratories focused on communication technologies—researchers from AMO GmbH, Ericsson, Nokia Bell Labs, and Imec have developed graphene-based photodetectors and modulators capable of receiving and transmitting optical data faster than ever before.
The aim of all this speed for transmitting data is to support the ultrafast data streams with an extreme bandwidth that will be part of 5G. In fact, at another section during MWC, Ericsson was presenting the switching of a 100 Gigabits per second (Gbps) channel based on the technology.
“The fact that Ericsson is demonstrating another version of this technology demonstrates that from Ericsson’s point of view, this is no longer just research,” said Kinaret.
It’s no mystery why the big mobile companies are jumping on this technology. Not only does it provide high-speed data transmission, but it also does it 10 times more efficiently than silicon or doped silicon devices, and will eventually do it more cheaply than those devices, according to Vito Sorianello, a senior researcher at CNIT.
Kinaret added: “We know that there are some challenges that we need to solve, but they are mostly in the manufacturing domain. It just takes time. There are no showstoppers that we see.”

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