Adaptive 3D Printed Nitinol Antenna Opens Up Possibilities for Military and Space Research

Antennas are essential for wireless communications, navigation, radar, radio communication and science. Their main function is to receive or transmit electromagnetic waves. Until now, antennas were rigid and inflexible, something that is about to change thanks to a project by researchers at the Johns Hopkins Applied Physics Laboratory (APL) in Baltimore. The project began in 2019 and the goal was to develop 3D technologies and shape-memory alloys for antennas that can deform independently based on temperature. These 3D printed antennas could contribute to the future of military and space research.
The innovative 3D printed antenna is designed to dynamically adapt to a wider range of radio frequencies and replace traditional antennas thanks to its greater flexibility. The idea for the project came from Jennifer Hollenbeck, who was inspired by the science fiction series The Expanse. In this series, aliens use organic technology to change shape. She explains, “I have spent my career working with antennas and wrestling with the constraints imposed by their fixed shape. I knew APL had the expertise to create something different.”

Photo Credits: Johns Hopkins Applied Physics Laboratory
The antenna was 3D printed from a nickel-titanium alloy, also known as Nitinol, one of the most popular shape memory alloys. This means that the alloy can recover its original shape after deformation when heated to a certain temperature, which is ideal for applications where materials must adapt to changing conditions. However, 3D printing posed some difficulties, such as printing the alloy in complex structures, as it deformed during fabrication and reacted to heat. Hollenbeck stressed, “It turned out to be a really complicated design, and it didn’t work as well as I would have liked.”
The problem was solved through several experiments and optimizations, which resulted in the first planar spiral antenna that adopts a conical shape when heated. In addition, a new conductor was used to bring the antenna to the required temperature without compromising its performance. “We have a lot of experience optimizing processing parameters and designs for alloys, but this was a step beyond,” explains Samuel Gonzalez, additive manufacturing engineer. “There aren’t many people out there, if anyone, printing this material, so there’s no recipe for how to process it.”
“We made shrapnel in the printer a few times because the antenna is trying to change shape as you’re printing it, due to the heat,” colleague Mary Daffron said. “It wants to peel apart.”
In the future, the flexible antenna should offer a new possibility for military operations, as it enables dynamic communication in the field. The antenna could also cover many mobile networks in the field of telecommunications and industry thanks to its adaptability, especially since switching between short-range and long-range communication can be better adapted. Another possible use would be in space exploration as an adaptive solution for missions in space. You can find more information about the 3D printed antenna here.
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