A radio antenna less than one-tenth of an inch long on a computer chip is another step in building an “ultrasmall radio chip” — a transceiver, processor and battery all placed on a chip not much larger than a pinhead, say University of Florida researchers.

Applications of tiny, cheap and disposable radios include pairing them with tiny, inexpensive sensors as a way of saturating large areas with sensing and communication capabilities.

For example, an electronic eavesdropping “fence” could alert authorities to anyone crossing the border illegally. Each radio would transmit information to the next radio, creating a single large network that could be monitored from afar.

Pairing the radios with force or strain sensors implanted throughout bridges, dams or tunnels would allow for reporting small defects before they mushroom into disastrous problems. Equipped with microphones, the radios also could make excellent covert listening devices, because they are so tiny and their individual signals so weak that they are difficult to detect both by with the naked eye and electronically.

University of Florida news release