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Wearable Wi-Fi Antenna

October 31, 2015 By Molly White in

New research suggests we could find ourselves wearing Wi-Fi within a few years, potentially paving the way for healthcare and other applications.

A new, ¨stretchable¨ antenna developed at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia may well hasten the coming of connected clothing. Using common copper wires, the wearable antenna is the first to have persistently maintained a stable Wi-Fi frequency despite being twisted and stretched, according to an IEEE Spectrum report.

In lab tests at KAUST, the wearable Wi-Fi antenna carried digital data signals an unprecedented 225 yards from a human test subject to a receiving device, according to an IEEE Spectrum report.

Wearable Wi-Fi

Taking the form of a helical spring – think of a Slinky – the research team layered the conducting copper antenna on top of a layer of polymer material to provide it the elasticity to return to its original shape and form after being stretched.

“The design helps us go for something where size can be compacted but can also conform with our body contours which are irregular, asymmetrical body surfaces,” said Muhammad Mustafa Hussain, an associate professor of electrical engineering at KAUST. “It can go with the flow.”

“The design helps us go for something where size can be compacted but can also conform with our body contours which are irregular, asymmetrical body surfaces,” KAUST associate professor of elecrtrical engineering Muhammad Mustafa Hussain was quoted as saying. “It can go with the flow.”

The addition of sensors could result in a wearable connected device that monitors physical conditions such as body temperature, oxygen saturation and blood pressure. The Wi-Fi antenna could transmit the data to devices in users’ homes or to nurses and doctors to monitor vital signs and other health parameters.

Standalone testing of the stretchable antenna showed it capable of transmitting data in the standard Wi-Fi frequency range up to 140 meters, the equivalent of about 1-1/2 soccer fields. Boosting transmission power from 1.25 to 10 milliwatts raised that to 394 meters.

With the help of pioneering flexible electronics researcher John Rogers of the University of Illinois the research team proceeded to stitch the stretchable antenna onto a piece of fabric worn on a test subject’s forearm and biceps. The device transmitted digital Wi-Fi signals up to 225 meters depending on power level.

A Big Breakthrough

That’s a huge step up compared to previous attempts to create connected clothing. To date, what has been developed can only transmit data short distances, up to about 10 meters, using low-power Bluetooth wireless technology, according to the IEEE report. Hussain said his group intends to substitute their stretchable antenna for the Bluetooth transmitter in a smartwatch and find if and how much its range would increase.

The flexible antenna could also be used in ¨Internet of Things¨ applications and help pave the way toward the ¨Internet of Everything,¨ whereby living as well as non-living things are all connected to digital networks, Hussain pointed out.

For just that reason Hussain and team have made a point of using readily available materials, such as copper, as opposed to ¨bleeding edge¨ nanomaterials.

They have also worked to assure the technology they use is compatible with today’s semiconductor manufacturing techniques. Hussain added that the flexible antenna might reach the commercial manufacturing stage in three years.

“Why wait 50 more years until nanomaterials qualify?” he was quoted as saying. “We can start with existing materials and technologies to make rigid devices into stretchable and reconfigurable ones.”