A car which starts on recognition of the driver’s jacket and a hospital gown that continuously measures and transmits a patient’s vital signs are just two of the applications envisaged with a new body area network-enabling fabric invented by engineers at the University of California, Irvine.

In a paper published recently in Nature Electronics, researchers at UCI’s Henry Samueli School of Engineering detail how they integrated advanced metamaterials into flexible textiles to create a system capable of battery-free communication between articles of clothing and nearby devices.

“If you’ve held your smartphone or charge card close to a reader to pay for a purchase, you have taken advantage of near-field signalling technologies,” said Peter Tseng, UCI assistant professor of electrical engineering and computer science. Our fabrics work on the same principle, but we’ve extended the range significantly. This means you could potentially keep your phone in your pocket, and just by brushing your body against other textiles or readers, power and information can be transferred to and from the device.”

Amirhossein Hajiaghajani, a UCI PhD student in electrical engineering and computer science, said the invention enables wearers to digitally interact with nearby electronic devices and make secure payments with a single touch or swipe of a sleeve.

“With our fabric, electronics establish signalling as soon as you hover your clothes over a wireless reader, so you can share information with a simple high-five or handshake,” he said. “You would no longer need to manually unlock your car with a key or separate wireless device, and your body would become the badge to open facility gates.”

Paired to talk

Tseng likens the technology to a railway that transmits power and signals as it crisscrosses a garment. The system allows new segments to be added readily, and separate pieces of clothing can be paired to “talk” with one another.

The near-field communications protocol has enabled the growth in applications such as wireless device charging and powering of battery-free sensors, but a drawback of NFC has been its limited range of only a couple of inches. The UCI researchers extended the signal reach to more than four feet using passive magnetic metamaterials based on etched foils of copper and aluminum.

The team’s innovation was designed to be highly flexible and tolerant of bodily motion. Because signals travel in the UCI-invented system via magnetic induction – compared to the continuous hard-wire connections that have been state-of-the-art in smart fabrics – it’s possible to coordinate separate pieces of clothing. In athletic gear, pants can measure leg movements while communicating with tops that track heart rate and other stats.

The applications in medicine are countless, Hajiaghajani said, such as freeing hospital staff from the task of applying numerous patient sensors, as they can all be integrated into metamaterial-equipped gowns.

The materials involved in the system are low-cost and easy to fabricate and customise, he noted, and varying lengths and branches of the metamaterial “rails” can be heat-pressed onto wearers’ existing clothing – with no need to go out and buy a brand-new enabled garment.

“Our textiles are simple to make and can be integrated with interesting wearable designs,” Hajiaghajani said. “We want to create designs that not only are cool and inexpensive but can reduce the burden that modern electronics can bring to our lives.”

Support for the project was provided by the US National Science Foundation.

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