3-D printers open new design space for wireless devices

May 04, 2017

DURHAM, N.C. -- Researchers at Duke University have 3-D printed potent electromagnetic metamaterials, using an electrically conductive material compatible with a standard 3-D printer.

The demonstration could revolutionize the rapid design and prototyping of radio frequency applications such as Bluetooth, Wi-Fi, wireless sensing and communications devices.

Metamaterials are synthetic materials composed of many individual, engineered devices called cells that together produce properties not found in nature. As an electromagnetic wave moves through the metamaterial, each engineered cell manipulates the wave in a specific way to dictate how the wave behaves as a whole.

Metamaterials can be tailored to have unnatural properties such as bending light backwards, focusing electromagnetic waves onto multiple areas and perfectly absorbing specific wavelengths of light. But previous efforts have been constrained to 2-D circuit boards, limiting their effectiveness and abilities and making their fabrication difficult.

In a new paper appearing online in the journal Applied Physics Letters, Duke materials scientists and chemists have shown a way to bring electromagnetic metamaterials into the third dimension using common 3-D printers.

"There are a lot of complicated 3-D metamaterial structures that people have imagined, designed and made in small numbers to prove they could work," said Steve Cummer, professor of electrical and computer engineering at Duke. "The challenge in transitioning to these more complicated designs has been the manufacturing process. With the ability to do this on a common 3-D printer, anyone can build and test a potential prototype in a matter of hours with relatively little cost."

The key to making 3-D printed electromagnetic metamaterials a reality was finding the right conductive material to run through a commercial 3-D printer. Such printers usually use plastics, which are typically terrible at conducting electricity.

While there are a few commercially available solutions that mix metals in with the plastics, none are conductive enough to create viable electromagnetic metamaterials. While metal 3-D printers do exist, they cost as much as $1 million and take up an entire room.

That's where Benjamin Wiley, Duke associate professor of chemistry, came in.

"Our group is really good at making conductive materials," said Wiley, who has been exploring these materials for nearly a decade. "We saw this gap and realized there was a huge unexplored space to be filled and thought we had the experience and knowledge to give it a shot."

Wiley and Shengrong Ye, a postdoctoral researcher in his group, created a 3-D printable material that is 100 times more conductive than anything currently on the market. The material is currently being sold under the brand name Electrifi by Multi3D LLC, a startup founded by Wiley and Ye. While still not nearly as conductive as regular copper, Cummer thought that it might just be conductive enough to create a 3-D printed electromagnetic metamaterial.

In the paper, Cummer and doctoral student Abel Yangbo Xie show that not only is Electrifi conductive enough, it interacts with radio waves almost as strongly as traditional metamaterials made with pure copper. That small difference is easily made up for by the printed metamaterials' 3-D geometry -- the results show that the 3-D printed metamaterial cubes interact with electromagnetic waves 14 times better than their 2-D counterparts.

By printing numerous cubes, each tailored to specifically interact with an electromagnetic wave in a certain way, and combining them like Lego building blocks, researchers can begin to build new devices. For the devices to work, however, the electromagnetic waves must be roughly the same size as the individual blocks. While this rules out the visible spectrum, infrared and X-rays, it leaves open a wide design space in radio waves and microwaves.

"We're now starting to get more aggressive with our metamaterial designs to see how much complexity we can build and how much that might improve performance," said Cummer. "Many previous designs were complicated to make in large samples. You could do it for a scientific paper once just to show it worked, but you'd never want to do it again. This makes it a lot easier. Everything is on the table now."

"We think this could change how the radio frequency industry prototypes new devices in the same way that 3-D printers changed plastic-based designs," said Wiley. "When you can hand off your designs to other people or exactly copy what somebody else has done in a matter of hours, that really speeds up the design process."
-end-
This work was supported by a Multidisciplinary University Research Initiative grant from the Office of Naval Research (N00014-13-1-0631).

Microwave Metamaterials Made by Fused Deposition 3D Printing of a Highly Conductive Copper-based Filament. Yangbo Xie, Shengrong Ye, Christopher Reyes, Pariya Sithikong, Bogdan Popa, Benjamin J. Wiley, and Steven A. Cummer. Applied Physics Letters, 2017. DOI: 10.1063/1.4982718

Duke University

Related Metamaterials Articles from Brightsurf:

Hyperbolic metamaterials exhibit 2T physics
According to Igor Smolyaninov of the University of Maryland, ''One of the more unusual applications of metamaterials was a theoretical proposal to construct a physical system that would exhibit two-time physics behavior on small scales.''

Origami metamaterials show reversible auxeticity combined with deformation recoverability
New research by Northwestern Engineering and Georgia Institute of Technology expands the understanding of origami structures, opening possibilities for mechanical metamaterials to be used in soft robotics and medical devices.

Temporal aiming with temporal metamaterials
Achieving a controllable manipulation of electromagnetic waves is important in many applications.

VR and AR devices at 1/100 the cost and 1/10,000 the thickness in the works
Professor Junsuk Rho of the departments of mechanical engineering and chemical engineering and doctoral student in mechanical engineering Gwanho Yoon at POSTECH with the research team at Korea University have jointly developed moldable nanomaterials and a printing technology using metamaterials, allowing the commercialization of inexpensive and thin VR and AR devices.

Virtualized metamaterials opens door for acoustics application and beyond
Scientists from the Hong Kong University of Science and Technology (HKUST) have realized what they called a virtualized acoustic metamaterial, in digitizing material response to an impulse response stored in a software program.

In acoustic waves, engineers break reciprocity with 'spacetime-varying metamaterials'
Working in an emerging field known to as 'spacetime-varying metamaterials,' University at Buffalo engineers have demonstrated the ability to break reciprocity in acoustic waves.

Induced flaws in metamaterials can produce useful textures and behavior
A new Tel Aviv University study shows how induced defects in metamaterials -- artificial materials the properties of which are different from those in nature -- also produce radically different consistencies and behaviors.

Researchers use metamaterials to create two-part optical security features
Researchers have developed advanced optical security features that use a two-piece metamaterial system to create a difficult-to-replicate optical phenomenon.

Artificial intelligence (AI) designs metamaterials used in the invisibility cloak
The research group of Prof. Junsuk Rho, Sunae So and Jungho Mun of Department of Mechanical Engineering and Department of Chemical Engineering at POSTECH developed a design with a higher degree of freedom which allows to choose materials and to design photonic structures arbitrarily by using Deep Learning.

Scientists take a 'metamaterials' approach to earthquake damage
At the SSA 2019 Annual Meeting, seismologists from around the world will discuss how metamaterial theory might be applied to everything from developing deflective barriers to manipulating the layout of buildings within a city as a way to minimize the impact of damaging surface seismic waves.

Read More: Metamaterials News and Metamaterials Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.