Experts from the US Naval Research Laboratory have designed and tested 3D printed antennas and arrays to advance radar technology and enable new applications for the US Navy.
The lightweight and fast production of 3D printed parts makes it an attractive alternative to traditional manufacturing that often requires expensive materials and specialized equipment.
"3D printing is a way to produce rapid prototypes and go through multiple design iterations very quickly and at minimal cost," said Anna Stumme, electrical engineer at NRL. "The light weight of the printed parts also allows us to take technology into new applications where the heavy weight of solid metal parts limited us."
Radar systems perform vital functions for the navy and remain an important part of maritime navigation and national defense. Antenna and array components, which are multiple connected antennas working together as one, can unexpectedly break or wear out and need to be replaced. Traditionally, metal parts are ordered or intricately machined, and production can sometimes take weeks. 3D-printed radar components, such as a cylindrical array, that provide 360-degree visibility, can be produced in hours instead of days with traditional methods due to reduced machining and assembly time.
In addition to the manufacturing benefits, the relatively low cost of 3D printing materials allows researchers to test multiple versions of parts with minimal overhead. The perfected prototypes can then be processed in the traditional way. Once a prototype has been successfully produced, be it 3D printed or traditionally manufactured, it must undergo rigorous testing before being used operationally. That's the "super power," say Stumme and her colleagues: they can quickly run all kinds of tests on new designs with 3D printed parts.
"We're not trying to say that we should print everything in 3D and put it on a ship, because that's not realistic," said Stumme. "We don't necessarily know how it would hold up in that environment. For us, it's a way to test more design iterations in a short space of time."
At the beginning of 2019, Stumme submitted a paper at the Antenna Applications Symposium comparing 3D-printed parts with traditionally manufactured parts. She won the student paper competition for her research.
Stumme and her colleagues are investigating how applications with limited weight and dimensions, such as unmanned aerial vehicles or small ships, can benefit from 3D printed parts. Many of the 3D prototypes are printed with lightweight nylon at the NRL's Laboratory for Autonomous Systems Research facility. Once the part is printed, it undergoes a process called electroplating.
During electroplating, a thin layer of metal is applied to the printed part. Electroplating provides a conductive surface so that the device can radiate as intended; something that is not feasible with just plastic. The result is a lightweight prototype that can then be evaluated for various characteristics, such as surface roughness – an important factor in the functionality of antenna elements.
Stumme works with NRL materials scientists from across the NRL, who perform critical characterization of the surface roughness. Surface roughness characterization provides an assessment of the coating on an antenna and its impact roughness on its performance.
"Surface roughness is important for waveguides 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 send and receive waves. So when a wave travels along a rough surface, it is distorted and the energy may not go where you want it."
Charipar and his team, part of NRL & # 39; s Material Science & Technology Division, are prototype 3D printed parts for NRL & # 39; s Radar Division. Once the part is created, researchers will investigate how the material characteristics affect the functionality of the radar. Each 3D printer has unique characteristics that can affect the product's performance. If researchers can figure out the optimal parameters for specific 3D-printed parts, Stumme and her colleagues agree that ships around the world can become self-reliant for those critical parts.
Despite current COVID-19 restrictions, research at the NRL continues to thrive remotely. Later this year, Stumme and her colleagues plan to demonstrate a new prototype of cylindrical array apertures for an X-band surveillance radar demonstration in a lab setting. The X-band surveillance radar is designed to search the area around a particular platform, such as a ship. They investigate the integration of cylindrical arrays in the masts of smaller ships using microwave photonics and optical fibers.
"Cylindrical arrays are beneficial because they provide a full 360 degree view," said Mark Dorsey, head of the antenna division of the radar analysis division of the radar division and principal investigator on the project. "Optical fibers are valuable because they allow long distances between the antenna itself and where processing takes place."
The use of optical fibers reduces the number of components required on the mast of a naval vessel, further reducing heat and weight limitations. The demonstration includes testing traditionally manufactured and 3D printed versions of the array to compare performance. Stumme designed both versions.
In 2021, the team will conduct field tests on the prototype. The demonstration will take place in the final year of their four-year effort to make the array more practical for use on smaller platforms, and to demonstrate how arrays can be easily used with optical fibers. The research is funded by NRL core funding.
New 3D-printed antenna designs reduce costs, weight and dimensions (2021, Feb 11)
retrieved February 11, 2021
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