Hard-wired antennas can be detected by their shadows and reflections in the RF bands. Additionally, unless they are hardened against it, extreme RF energy, as might be generated by an EMP or by a highly-directional attacking antenna, can damage circuits connected to the receiving antenna.

When the plasma antenna is turned off, it stops existing. There's nothing there to attack or detect.

A possible future advantage would be shaping the plasma with magnetic fields, to create customizable antenna geometries, or geometries that electrically extend beyond the physical bounds of the equipment. Imagine using a laser small enough to fit in a backpack to create a 1/4 wave antenna long enough to transmit or receive at 30 kHz, with length 2.5 km .

You could create a plasma antenna 2500m long, send a message to a submarine 150 m below the surface, then it just disappears when you turn it off.

What a cool visual. Setting up a small beacon like object on the ground, standing back a couple hundred feet, and then a beam of bright blue light bursts several kilometers into the air, sending a quick burst of data while the capacitors powering it can keep it alive.

If using multiple converging lasers, the antenna need not be connected to the equipment. Two lasers could ionize the air in a line 2500m long, and a third could excite the center of it in a modulated fashion. That would be transmit only, unless you had some way to measure the energy levels at that center point from a distance.

It would be unlikely to glow brightly enough in the visual spectrum to see in the daytime, but it would be pretty cool at night.

Thank you.

Normally antennae are constructed out of solid materials. The plasma is controlled by electricity, so the gain characteristics can be rapidly controlled and dynamically tuned in real-time (possibly).

So, like the ultimate SDR?

It's related, but not the same. SDR happen after you received your signal, where you can, in software, pick different ways of decoding the signal.

This, however lets you dynamically choose the antenna length, and each frequency has a perfect length that works best for it.

So the two are complimentary, but at different parts of the process.

Right so it's like SDA - a software defined antenna

For normal people... pretty much nothing. You need power to keep the plasma hot, it's a safety hazard, and it's not cheap. For electrically-small antennas it looks like it might be slightly more efficient than a wire antenna of the same size (or slightly smaller than a wire antenna of the same efficiency) but most of the advantages listed pertain to military applications, and that seems to be who's driving the research.

>> For normal people... pretty much nothing.

Did you even read the article? They mention Solid State Plasma antennas, which can be fabricated using standard silicon chip fabrication techniques.

It is said it could be used for 60ghz wifi (wisig)

I guess with a metal antennae you have a permanently reflective surface, AIUI once one of these are disabled they become basically radio-transparent again, which means less of a blip on radar

It also means they don't receive when off, which renders them resistant to some forms of electronic warfare.

It's tunable for one, and it might be very fast to tune. At very high frequencies these are targeting (>50ghz), making an antenna suitably wideband to cover the entire bandwidth of some service is difficult and might result in a compromised antenna.

For security applications, the ability to turn it off is kind of nice; no antenna = no backscatter. OTOH how stealthy can a plasma antenna be when it is on?