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An NRL researcher tests a new 3D-printed antenna design.

U.S. Naval Research Laboratory (NRL) experts created and tested 3D-printed antennas and arrays to advance radar technology and enable new applications for the U.S. Navy. The lightweight and rapid production of 3D-printed parts make it an attractive alternative to traditional manufacturing that often requires expensive materials and specialized equipment.

Radar systems perform critical functions for the Navy and remain an important part of maritime navigation and national defense. Parts for antennas and arrays, which are multiple connected antennas working together as one, may unexpectedly break or wear out, requiring replacement. Traditionally, parts are ordered or intricately machined out of metal, sometimes taking weeks to produce. 3D-printed radar parts, such as a cylindrical array, which provide 360-degree visibility, can be produced within hours versus several days using traditional methods due to the reduced machining and assembly time.

In addition to production benefits, the relatively low cost of 3D printing materials enable researchers to test multiple versions of parts at minimal overhead. The perfected prototypes can then be machined using traditional methods. Once a prototype is successfully produced, whether 3D printed or traditionally manufactured, it must undergo rigorous testing before it is used operationally.

NRL electrical engineer Anna Stumme and her colleagues are investigating how weight-and-size-constrained applications, such as unmanned aerial vehicles or small ships, can benefit from 3D-printed parts. Many of the 3D prototypes are printed using light weight nylon in NRL’s Laboratory for Autonomous Systems Research facility. Once the part is printed, it undergoes a process called electroplating. During the electroplating process, a thin coat of metal is applied to the printed part. Electroplating provides a conductive surface for the device to radiate as intended; something that isn’t feasible with plastic alone. The result is a lightweight prototype that can then be evaluated for a variety of attributes, such as surface roughness - a major factor in the functionality for antenna elements.

Stumme collaborates with NRL materials scientists from across the NRL who perform critical surface roughness characterization. Surface roughness characterization provides an assessment of the coating on an antenna, and the impact roughness has on its performance.

“Surface roughness is important for wave guides and antennas because it can cause scattering losses and result in a less efficient antenna,” said Nick Charipar, head of the Applied Materials and Systems Section. “Antennas radiate and receive waves. So, if a wave runs along a rough surface, it is distorted and the energy may not go where you want it to go.”

Charipar and his team, part of NRL’s Material Science & Technology Division, prototype 3D printed parts for the NRL’s Radar Division. Once the part is created, researchers investigate how the material features impact functionality of the radar. Each 3D printer has unique characteristics that may alter product performance. If researchers can figure out the optimal parameters for specific 3D printed parts, Stumme and her colleagues agree ships could become self-reliant for those critical parts anywhere in the world.