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.
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