Mobile antennas in the 5G range are small, which makes them easy to integrate into electronic circuits; here they are on a millimeter-wave beamformer circuit. Newer 6G antennas will be even smaller. (Photo: Mohammad Sharawi)

While "5G" - aka the fifth generation - of standards for mobile telephony is currently being deployed in cities, engineers are working on the technology that will succeed it, “6G”. Professor Mohammad Sharawi is part of this group, and with his team, is developing and testing the next range of antennas. Antennas as tiny as the tip of a few strands of your hair!

Over the past 40 years, cellular device antennas have gradually become smaller and smaller. The first antennas that could host a long antenna of 30 centimeters, gave way to devices with shorter antennas. Today, these important elements are even more imperceptible, hidden behind the screen of smart phones.

You'd perhaps think there's an aesthetic reason behind this shrinkage, but in fact, no. If antennas are smaller today, it's above all so they're able to capture and emit waves at higher frequencies. So, the reason is physical, and we'll return to this later.

Microscopic antennas

Each new generation of cell phones comes with a new frequency range, always higher in the band than previous ones. In the 1990s, antennas had to pick up waves around 900 megahertz (MHz). Today with 5G, they target frequencies ranging from 10 to 50 gigahertz (GHz), or 10,000 to 50,000 MHz, in the shortwave region of the electromagnetic spectrum.

And we haven't stopped climbing yet.

In his Polytechnique Montréal laboratory, Associate Professor Mohammad Sharawi from the Department of Electrical Engineering is developing the next generation of antennas. So where do these antennas transmit? In frequencies from 0.1 to 0.3 Terahertz (THz), or 100 000 to 300 000 MHz.

Why go after frequencies of another order of magnitude? “Simply because they make it possible to push a lot more data, more quickly,” explains Professor Sharawi.

Until now, all cellular technologies have exploited frequencies located in a thin band of the electromagnetic spectrum, located between that of radio waves and that of microwaves. By targeting frequencies of the order of Terahertz, in a region of the spectrum corresponding to the far infrared, we get a little closer to light waves, and the transmission capacities of fiber optics.

"At these frequencies, we should reach transmission speeds of the order of one terabyte per second. “We'll open the door to new applications, in addition to improving those that rely on 5G, and that require instantaneous data exchange."

Among these applications and uses, the engineer mentions autonomous vehicle technology which is largely based on the exchange of data. “Higher transmission speeds will also make it possible to perform remote surgeries, or even fly an airplane remotely. The important thing is to reduce latency as much as possible."

Professor Sharawi notes that this next generation's antennas will be so small that they can be incorporated into integrated circuits or electronic chips. New ways of using antennas will also be considered, he adds. “For example, they'll be so small that we could integrate them into windowpane glass in order to facilitate the exchange of data entering and leaving buildings."