A wireless antenna, which is small enough to be worn discreetly under clothes and allows doctors to monitor illnesses and injuries remotely, is closer to becoming a reality. The antenna, which could be as thin as 1cm, can channel signals along human skin and help broadcast signals over your body to connect up medical implants or portable gadgets. The new power-efficient approach could make more of established medical devices like pacemakers or help future implants distributed around the bodywork together. Just one of the small hockey-puck-like antennas developed at Queen's University Belfast, Northern Ireland, would be able to connect to gadgets anywhere else on the body, says William Scanlon who made the design with colleague Gareth Conway. The new design's ability to produce signals that creep along the skin makes it more efficient than existing battery-hungry technologies such as Bluetooth, says Scanlon - an important factor for medical devices, which need long life spans. Scanlon and Conway's brainchild channels much more of its signal sideways by taking advantage of the "creeping wave" effect that allows waves to travel along a surface. The same effect is responsible for both a person's ears hearing a sound only directed at one side of their head. Monopole antennas stand on a plate of conductive material - like a car roof - to reflect signals travelling downwards. But Scanlon and Conway have shown that turning the design upside down, putting the plate on top of the antenna and away from the body, helps channel signals along the skin. "There is a mismatch between the air and the body tissue, which causes a reflection of sorts," New Scientist quoted Scanlon, as saying. Signals are channeled out sideways along the skin by this reflection and the conducting plate. That makes the antenna more efficient, which could double the battery life of body-worn gadgets, Scanlon says. "The idea of inverting the antenna to encourage surface wave propagation around the body is worth patenting," John Batchelor, University of Kent, who is working on similar devices.