Dr. Skorobogatiy’s team has designed a THz-wave multiplexer using additive printing that could serve as a model for future 6G technology. (Photo : Maksim Skorobogatiy)

While the fifth generation of mobile telephony standards (5G) is being rolled out in our cities, engineers are working on the technology that will succeed it: 6G. Professor Maksim Skorobogatiy is one of them. He and his team have just revealed in an article published in Nature Communications journal how additive printing could be used to manufacture some of the components that will operate in the terahertz band waves.

Every new generation of mobile telephony comes with its new frequency range, always higher than the previous one. In the early 1990s, antennas had to pick up waves around 900 megahertz (MHz). Today, with 5G, they are targeting frequencies from 10 to 50 gigahertz (GHz), or 10,000 to 50,000 MHz, in the short-wave region of the electromagnetic spectrum.

And it won’t stop there.

In his lab at Polytechnique Montréal, Maksim Skorobogatiy, a full professor in the Department of Engineering Physics, is developing some of the next generation of components that will make 6G possible. These components will have to operate at frequencies ranging from 100 GHz to 10 terahertz (THz), i.e., from 100,000 to 10 million MHz.

This is an exciting challenge according to the man who also holds the Canada Research Chair in Ubiquitous Terahertz Photonics. “This is the next frontier for wireless communications,” he says. “There’s still a lot of work to be done to transmit these waves, but also to detect them and modulate them with data.”

Why tackle frequencies of this magnitude? Simply because they will push much more data, faster. The throughput could be as high as one terabyte per second, enough to transmit the equivalent of 1,000 Netflix movies in a second. When put in those terms, this advance may seem frivolous. But when you think of applications like remote surgery and autonomous transport, it starts to make sense.

Before this happens, however, a new range of tools adapted to THz frequency waves will have to be developed. The Polytechnique Montréal team is doing just that.
 

Towards 6G

In a paper recently published in Nature Communications, Professor Skorobogatiy and his team unveiled a simple and low-cost approach to manufacturing some of the components that will be central to future 6G technology by presenting the case of a multiplexer/demultiplexer as a proof of concept.

The multiplexer/demultiplexer is a device that picks up several signals at once and then brings them together to transmit all the information in a single channel. An example of this is the audio and video signals of a movie. Pairing signals increases the amount of data transmitted over a network. The device also works in the opposite direction to split multiple mixed signals into individual data streams.

The Polytechnique team’s device relies on additive manufacturing to design the core of the multiplexer out of plastic. A thin layer of silver is then deposited on the sections that transmit the waves so as to make so-called “plasmonic” waveguides.

“Normally, lithography and silicon wafer etching processes are used to manufacture this type of device, which requires extremely expensive facilities,” says Professor Skorobogatiy. “With our approach, we’re proposing a low-cost way to manufacture the devices that will be used for 6G.”