Now you see it …. now you don’t!

Undetectable, covert transmissions made from the depths of enemy territory may soon be possible thanks to work carried out at the Australian National University’s Plasma Research Laboratory.

An antenna developed by Gerard Borg and his team uses ionised gases instead of metals for the radiation of electromagnetic waves. The project has come about in response to a DSTO (Defence Science & Technology Organisation) contract to develop an antenna that isn’t easily detectable by radar. The result, claim its creators, can be made invisible in an instant.

The basic plasma antenna consists of an evacuated glass tube containing a gas (noble gases and air have been successfully tested)) into which a radio wave is shot by a single electrode. The gas is stripped of electrons as the radio wave moves up the antenna, ionising the gas to form a plasma. The plasma derives electrical properties from the motion of these free electrons and so behaves like a metal. However, unlike a metal, when the electrode at the base of the antenna is turned off, the gas inside can be de-energised in microseconds, rendering the antenna invisible to radar.

While the development of an antenna is still the project’s main aim, Borg is also working with a number of companies (including CEA Technologies) to develop commercial applications for this technology.