Northeastern researchers have introduced a new class of technologies that could be key in helping combat network congestion.
In wireless communication, spectrum — radio frequencies that allow devices to communicate over the air — is king.
But spectrum, like all resources, is finite, and as more devices are brought online and data speeds increase, wireless networks are becoming overcrowded. It’s a problem that is expected to get worse as the 5G infrastructure continues to get built out and 6G technologies are introduced.
Cristian Cassella, a Northeastern associate professor of electrical and computer engineering, understands this problem better than most; it’s one of his areas of focus at the university’s Microsystem Radio Frequency Laboratory, which he leads as its principal investigator.
Taking advantage of metamaterials — a class of engineered materials not found in nature — Cassella and his team have introduced new microelectromechanical technologies that could be key in helping combat network congestion.
For his efforts, Cassella was recently awarded the IEEE European Frequency and Time Forum Young Scientists Award, a prestigious honor given to a researcher working in the field of metrology who is under the age of 40.
To understand the science behind Cassella’s work, it’s first important to understand some of the technology inside your cellphone.
Your cellphone is great for making calls, texting and surfing the web. Those actions are completed using a range of different wireless signals that are received using a phone’s array of antennas and dedicated components.
A key component is a phone’s radio frequency filter, which allows various wireless signals that are simultaneously received, such as WiF, Bluetooth, and many others, to be separated and siloed before being sent to the appropriate circuitry for data decoding, Cassella says. Think of it like a telephone operator routing calls to the appropriate parties.
“It seems like a simple operation, but regardless of how it looks, it’s extremely difficult to do with the technology that is out there,” says Cassella, noting that much of the technology inside those filters is more than 20 years old.
Taking advantage of research funding from the National Science Foundation, Cassella set out to improve the technology using acoustic-wave based metamaterials.
“The type of behavior that we are trying to address is exotic behavior of acoustic waves at the micro scale,” says Cassella. “The devices we work on are piezoelectric, and the main idea of those devices is that they use an electrical signal that generates an acoustic wave.”
By tapping into a device’s electrical system, Cassella and his team are able to modulate its performance and build filters that offer up wider bands of connectivity that are capable of sensing signals more precisely.
But Cassella’s discoveries extend beyond communication devices to other micro technology applications. He points to his chip scale metamaterials being able to address sensing needs that are hard to achieve with the other technologies out there.
In one of his recent work, published in Nature Communications, he has discussed the opportunity to use metamaterials to sense extremely localized parameters, such as the mass of a single blood cell.
“This research direction has the potential to provide new diagnostic means for precise detection and characterization of diseases or, in a completely different setting, can push the current limits of existing inertial sensors, allowing positioning and navigation of vehicles that operate in high shock and vibration environments,” he says.
“All these bigger ambitions require new electronic devices,” he adds. “What we are trying to accomplish here is sensing things that previous devices were not able to sense because they were simply just too small to be driven with enough strength to have a high-fidelity output signal carrying the information that needs to be sensed.”