A team of researchers from the University of California Berkeley’s Department of Materials Science and Engineering has developed a new 3D printing/additive manufacturing platform that offers unparalleled flexibility in antenna design and ability to rapidly print intricate antenna structures.
Today, nearly all personal electronic devices rely on antennas to send and receive data. Demand is also rising for lightweight antennas for new applications, including the latest in 5G/6G networks, advanced wearable devices and aerospace applications such as CubeSats. However, standard manufacturing techniques have limited the structural complexity and use of multiple materials that would unlock still more features and capabilities from antennas.
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The newly developed platform – dubbed charge programmed multi-material 3D printing (CPD) – is a universal system for the rapid production of nearly all 3D antenna systems. It can pattern highly conductive metals with a wide range of dielectric materials into a 3D layout.
The platform isn’t an expensive 3D printer for metals that would involve pricey metal powders and high-energy lasers. ‘This technology can be applied to desktop-friendly light-based printers,’ said associate professor Xiaoyu (Rayne) Zheng, the faculty co-director of the Berkeley Sensors and Actuator Center (BSAC) and the Jacobs Institute for Design Innovation.
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The CPD method combines a desktop digital light 3D printer and a catalyst-based technology that can pattern different polymers at different locations where they will attract metal plating. Its auto-catalytic or selective plating technology enables the polymers to selectively absorb metal ions into prescribed locations that are defined by the desired antenna design outcome.
CPD can broadly integrate with a variety of multi-material 3D-printing methods, Zheng said. ‘It allows essentially any complex 3D structure, including complex lattices, and has demonstrated deposition of copper with near-pristine conductivity, as well as magnetic materials, semiconductors, nanomaterials and combinations of these.’
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Zheng has been working on the CPD platform since 2019, when his group first came up with the concept. In 2020, his team published their first paper in Nature Electronics on the technology, followed by a 2022 paper in Science that described its use in the construction of microrobots.
The new research is specific to the antenna application. CPD, Zheng said, is ‘very uniquely suited for antennas, because nearly all antennas need two components: one is the metal phase, the conductor, and the other is the dielectric phase, which is not conductive – and [until now] there has been no technology capable of directly patterning or synthesising the conductor and dielectric materials together.’
Zheng explained that the first application they considered was in antennas. After discussing the technology with colleagues who specialise in this area, they realised that this technique could revolutionise how antennas are printed and open many new design possibilities.
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Printing both the conductor (metal) and dielectric materials is especially important for antennas to be used in extreme environments. For example, Zheng said, ‘you cannot use a regular polymer in space. You need a high-temperature polymer like Kapton, which is a good material in aerospace [stable at both very high and very low temperatures]. Now you can have Kapton and a pattern of metal traces interwoven in 3D at the same time.’
The team has also shown that through proper 3D designs, these antennas, without having to sit on a bulky substrate, achieve substantial weight savings compared to current antennas.
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According to Yahya Rahmat-Samii, professor of electrical and computer engineering at UCLA, the CPD platform could significantly expand the possibilities for new antenna technologies and enable data-drive designs – allowing out-of-the box antenna designs for diverse applications. ‘There are probably numerous different antenna structures, depending on the application you have in mind,’ he said.
Zheng and Rahmat-Samii next want to explore the full complexity of antenna design achievable with their new technology. Control of an antenna’s complexity gives them control over the ability to shape electromagnetic waves, much as a painter controls the application of paint with a brush. Aiming to advance applications for this technology, the team at UC Berkeley has formed a start-up company focused on flexible medical sensors that would conform, say, to the shape of a hand.
‘We can achieve a tuneable antenna,’ Zheng said. ‘And so the question now is, where can that technology help us best?’
The research has been published in Nature Communications.