Antennas can be embedded directly into military clothing

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Ohio State University researchers are finding ways to incorporate radio antennas directly into clothing using plastic film and metallic thread.

In the current issue of the journal IEEE Antennas and Wireless Propagation Letters, the researchers report a new antenna design with a range four times larger than that of a conventional body-worn ‘whip’ antenna used by US soldiers today.

‘Our primary goal is to improve communications reliability and the mobility of the soldiers,’ said Chi-Chih Chen, a research associate professor of electrical and computer engineering at Ohio State. ‘But the same technology could work for police officers, firefighters, astronauts — anybody who needs to keep their hands free for important work.’

The Ohio State system surrounds the body with several antennas that work together to transmit or receive a signal, regardless of the direction a person is facing.

An integrated computer-control device senses body movement and switches between the antennas to activate the one with the best performance given the body’s position.

The result is claimed to be a communications system that can send and receive signals in all directions without the need for the wearer to carry an external antenna.

The engineers created a prototype antenna by etching thin layers of brass onto FR-4, a commercially available plastic film that is light, flexible and can be sewn onto fabric.

They attached it into a vest at four locations — chest, back and both shoulders. The computer controller — a metal box a little smaller than a credit card and 1in thick — was worn on a belt.

In laboratory tests, the experimental antenna system provided significantly greater signal strength compared with a conventional military ‘whip’ antenna, enabling a range of communications four times larger.

Chen currently estimates that the antenna systems, as demonstrated in the prototype, would cost $200 (£120) per person to implement, but mass production would bring that cost down.