Stealthy, Versatile, and Jam Resistant Antennas made of Gas

This prototype plasma antenna is stealthy, versatile, and jam-resistant. Credit: T. R. Anderson and I. Alexeff

A new antenna made of plasma (a gas heated to the point that the electrons are ripped free of atoms and molecules) works just like conventional metal antennas, except that it vanishes when you turn it off.

That's important on the battlefield and in other applications where antennas need to be kept out of sight. In addition, unlike metal antennas, the electrical characteristics of a plasma antenna can be rapidly adjusted to counteract signal jamming attempts.

Plasma antennas behave much like solid metal antennas because electrons flow freely in the hot gas, just as they do in metal conductors. But plasmas only exist when the gasses they're made of are very hot. The moment the energy source heating a plasma antenna is shut off, the plasma turns back into a plain old (non conductive) gas. As far as radio signals and antenna detectors go, the antenna effectively disappears when the plasma cools down.

The antenna design being presented at next week's APS Division of Plasma Physics meeting in Orlando consists of gas-filled tubes reminiscent of neon bulbs. The physicists presenting the design propose that an array of many small plasma elements could lead to a highly versatile antenna that could be reconfigured simply by turning on or off various elements.

Source: American Physical Society

   

• earls - Nov 12, 2007
  • Rank: not rated yet
  Wow, that's scary, I was just pondering this idea within the past two weeks. I simply figured that denser metal antennas would be superior... But I can see how these types can have their advantages.
  • report abuse
  • • Current rank
    • 1
    • 2
    • 3
    • 4
    • 5
• Graeme - Nov 12, 2007
  • Rank: not rated yet
  The idea has been around for years, and isn't the plasma more visible than the equivalent wires? Turning on and off is a good advantage though!
  • report abuse
  • • Current rank
    • 1
    • 2
    • 3
    • 4
    • 5
• loboy - Nov 12, 2007
  • Rank: 5 / 5 (1)
  Tesla developed a similar array in his "Teleforce proposal". The drawing is titled "New Terminal for Exceedingly High Potentials Consisting of Spherical Frame with Attachments".
  
  Except Tesla never mentions phasing the array, which is somewhat suggested in the article. He does mention in the proposal that it is a "transmitter".
  • report abuse
  • • Current rank
    • 1
    • 2
    • 3
    • 4
    • 5
• Argiod - Nov 13, 2007
  • Rank: 1 / 5 (1)
  loboy, indeed, Tesla was way ahead of his times. And he was suppressed because his ideas were so radical for the times, the gov't was likely afraid of him and his inventions. After all, you can't trace ballistics on pure energy, can you? Granted, his terminology is somewhat antiquated now; but it is a simple matter to translate his terms into modern equivalents to see that we're only now beginning to catch up with his ideas.
  • report abuse
  • • Current rank
    • 1
    • 2
    • 3
    • 4
    • 5