By Jay Kakade 28 Nov, 2024
Collected at: https://www.techexplorist.com/new-shape-memory-alloy-antenna-transform-communications/93557/
After being inspired by The Expanse series, researchers at the Johns Hopkins Applied Physics Laboratory have utilized novel manufacturing techniques and shape memory alloys to craft an antenna that changes shape based on temperature. The team asserts that the technology could find its way into military, scientific, and commercial applications.
Once the fixed-shape antenna is manufactured, its characteristics are limited, which limits many of its operating parameters. To facilitate new realms of operational agility, a shape-changing antenna could enable a wider array of radio-frequency (RF) bands.
Such shape-shifting antennae could replace multiple antennas, dynamically adapt to spectrum availability, and change shape in response to short—and long-range communications. Researchers turned to shape memory alloys to advance the manufacturing of such dynamic hardware.
These shape memory alloys are metallic materials that return to their original shape after being deformed when heated, stressed, or strained. For reference, these alloys are used in orthodontic wires, vascular stents, and bone implants for control surfaces in spacecraft.
Materials scientist Andy Lennon had already used nitinol – a shape memory alloy of nickel and titanium, to create coils extending down through a person’s esophagus to assist with heart imaging. Lennon and his team were working on shaping nitinol into complex shapes. However, these alloys need periodic mechanical processing called cold work.
“Doing an extreme amount of cold work would defeat the whole point,” Lennon said. “If you take that complex shape and pass it through a die to stretch it out, you’re back to a wire.“
Therefore, researchers at APL started working on challenges associated with scalable additive manufacturing and later applied these techniques to craft shape-changing materials. The team altered the ratio of nickel and titanium to create a shape-changing horn antenna. Though the antenna expanded and contracted, the deformation was relatively rigid and challenging.
“It turned out to be a really complicated design, and it didn’t work as well as I would have liked,” Hollenbeck said.
Learning from the previous experiments, the lead author integrated nitinol with two-way shape memory. Here, the alloys can be cooled and heated between two remembered shapes.
After collaborating with electrical engineers at Force Projection Sector, the team developed an antenna that, when cool, resembled a flat spiral disk but became a cone spiral when heated.
However, heating the spiral emerged as another challenge. Researchers were keen to find a way to heat the antenna accurately enough to change shape without burning the internal structures. To solve this issue, the team had to invent a new power line.
“For peak heating, the power line has to handle a lot of current,” Sherburne said.
After being all set, the team encountered a challenge in 3D printing this antenna. Due to heat, the materials tried changing shape during the printing process.
Since the team has accomplished the processing parameters, they look forward to building their initial success.
“The shape-shifting antenna capability that has been demonstrated by this APL team will be a game-changing enabler for many applications and missions requiring RF adaptability in a low-size and -weight configuration,” said APL Chief Engineer Conrad Grant.
“This is yet another powerful example of the innovation that occurs at the Laboratory through motivated, highly capable, multidisciplinary teams.“
Journal Reference
- Sherburne, Michael; Sibert, Kyle; Daffron, Mary; Lennon, Andrew; Feldmesser, Howard; Furer, Josh; et al. (1753). Two-Way Additively Manufactured Shape Memory Alloy Wideband Reconfigurable Compound Antenna. ACS Applied Engineering Materials. Journal contribution. DOI:
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