Researchers make wearable antenna breakthrough

Researchers at the Ohio State University have created something they claim could revolutionise the way communication devices operate: a wearable antenna design some four times more efficient than today's solutions.

Wearable antennas - typically woven into clothing using metallic threads on plastic film - are nothing new, and have long been considered for use in the battlefield as a way of enhancing the range of a soldier's communication equipment without giving him or her a massive antenna sticking out of a backpack.

While they're useful, their efficiency isn't great, and it's that lack of performance which stops them being used for anything more than hobby projects. A report published in the scientific journal IEEE Antennas and Wireless Propagation Letters covering a new design by a team led by Professor Chi-Chih Chen of Ohio State University promises to change that by allowing multiple antennas to be combined into a single item of clothing.

"Our primary goal is to improve communications reliability and the mobility of the soldiers," explained Chen of his work. "But the same technology could work for police officers, fire fighters, astronauts – anybody who needs to keep their hands free for important work."

The new design is omnidirectional and features a range some four times larger than previous efforts, surrounding the body with multiple antennas in order to avoid issues of occlusion as the user moves and shorting from contact with the skin. A centralised control device detects which antennas are not functioning correctly and ensures that the right mix of antennas are used to get the maximum performance.

The prototype created at the university comprises an etched layer of brass on a commercially available plastic film, which creates an antenna which is light, flexible, and ready to sewn on to fabric. By attaching antennas at four locations - chest, back, and both shoulders - and adding the small controller on a belt, the team were able to send and receive signals with a range some four times larger than a conventional military 'whip' antenna.

The team's creation has other benefits beyond increased range: by removing the traditional antenna, the communication system becomes lighter and more portable - and significantly less obvious if stealth is a requirement. While the cost is high - around $200 per person, Chen estimates - mass production would bring the total down rapidly.

Professor John Volakis, director of the Electroscience Lab at Ohio State University, believes that the team's work has potential benefits for civilian life, too. "Imagine a vest or shirt, or even a fancy ball gown made with this technology," he mused. "The antennas would be inconspicuous, and even attractive. People would want to wear them."

To further that goal, the team is currently working on printing antennas directly on to a variety of materials including cotton, further reducing the cost and increasing the flexibility.