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Tiny Membrane-Based Antennas

Membrane-based antennas can be hundreds of times smaller than regular ones

2 min read
Illustration: Northeastern University/Nature Communications
Illustration: Northeastern University/Nature Communications

New membrane-based antennas could be nearly 100 times smaller than the most compact current antennas, a new study finds.

These antennas could find use in portable wireless communications systems, including wearable electronics, smartphones, bio-implantable antennas, bio-injectable antennas, bio-ingestible antennas, and the Internet of Things, researchers say.

State-of-the-art compact antennas are designed to resonate at specific wavelengths. But their miniaturization is limited to roughly one-tenth of their resonant wavelengths.

The new antennas developed by researchers at Northeastern University and their collaborators can now be shrunk to sizes as small as one-thousandth of the wavelength they aim to receive and transmit—without any degradation in performance. The researchers detailed their findings online today in the journal Nature Communications.

These new antennas consist of thin membranes made up of two different kinds of films. Its piezomagnetic iron-gallium-boron layers convert mechanical oscillations to magnetic signals and vice versa. They are paired with piezoelectric aluminum nitride films, which convert mechanical oscillations to electrical signals and vice versa.

When these membranes receive electromagnetic signals, their magnetic layers sense the magnetic fields of these electromagnetic waves. This causes the membranes to vibrate, which piezoelectrically generates a voltage.

Conversely, in order for the antennas to transmit, they vibrate. This causes the magnetic layers of the membranes to generate a magnetic current that radiates electromagnetic waves.

The sizes of these “magnetoelectric” antennas depend on the wavelengths of the acoustic vibrations they operate with instead of the electromagnetic signals they receive and transmit. Because these acoustic wavelengths are about 100,000 times shorter than their corresponding electromagnetic wavelengths, these new antennas can be much smaller than conventional antennas.

“This acoustic antenna concept changes the fundamental principle on which antennas have been designed for over a century, and can lead to dramatically compact antennas with improved performance,” says study senior author Nian-Xiang Sun, an electrical engineer and materials scientist at Northeastern.

In experiments, these nanoelectromechanical system (NEMS) antennas could receive and transmit at VHF and UHF radio frequencies. In addition, they are completely passive, requiring simple electronics and no battery.

Future research will attempt to improve antenna performance through new materials, new designs and better fabrication processes, Sun says. “These are the first magnetoelectric antennas that have been demonstrated, which are not perfect,” he says. “We see a lot of room of improvement.”

The Conversation (0)

Why the Internet Needs the InterPlanetary File System

Peer-to-peer file sharing would make the Internet far more efficient

12 min read
An illustration of a series
Carl De Torres

When the COVID-19 pandemic erupted in early 2020, the world made an unprecedented shift to remote work. As a precaution, some Internet providers scaled back service levels temporarily, although that probably wasn’t necessary for countries in Asia, Europe, and North America, which were generally able to cope with the surge in demand caused by people teleworking (and binge-watching Netflix). That’s because most of their networks were overprovisioned, with more capacity than they usually need. But in countries without the same level of investment in network infrastructure, the picture was less rosy: Internet service providers (ISPs) in South Africa and Venezuela, for instance, reported significant strain.

But is overprovisioning the only way to ensure resilience? We don’t think so. To understand the alternative approach we’re championing, though, you first need to recall how the Internet works.

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