Original URL: http://www.theregister.co.uk/2012/02/14/spray_antennas/

SPRAY-ON antennas waved about at Google's techfest

Turning the world into an aerial

By Bill Ray

Posted in Broadband, 14th February 2012 12:43 GMT

Presenting at the new Google-backed talk fest "Solve for X", ChamTech Operations showed its nano tech-based antenna in a spray can, turning trees into antennas and connecting submarines by radio.

The technology is easy to explain, but rather harder to realise. It comes in a aerosol with which one sprays nano-capacitors – onto a tree, pole or something shaped similarly – to turn an upright body into a radio antenna. Apply the nano-tech coating to an existing antenna and it will extend the range by 100 times, stick it underwater and you can send a radio signal over a mile.

ChamTech's CEO presented the concept at Google's TED-competitor. His hyperbolic assertions contrasted with a monochromic delivery style, but get two minutes thirty secs into the video and you can see a tree being used as a radio antenna.

ChamTech's assertion is that existing antennas generate heat, which is wasted energy, though the presenter's implication that they haven't evolved at all over the last 100 years is rather disingenuous. Radio antennas have evolved markedly, and there's still constant innovation in antenna design, even if much of it is conducted on a trial-and-error basis.

What is unclear from the presentation is how the size of the antenna is managed - radio aerials have a size related to the size (frequency) of the radio signal they are trying to receive (or transmit). To pick up Radio 4 (at 94MHz) one should, ideally, have an antenna a shade over three metres long. That's a little cumbersome, so we generally use fractions, and adjust the length of the antenna to pick up different frequencies.

But even if one has to measure the sprayed area accurately, the idea still has huge potential, and if used to cover an existing antenna the size is already perfect.

When applied to the antenna of an RFID tag (Seven minutes into the video) the coating apparently boosted the range from one-and-a-half meters to over 200m, and while applying a layer to antennas used for undersea communications (which is very limited in range as radio doesn't really penetrate water, even at 50MHz) it pushed the range from 30 meters to more than 1.6km (1 mile), which has huge implications for notoriously difficult submarine communications.

Clearly the technology has huge potential, if only as a coating to reduce the power consumption of existing antennas. Promises of self-powered base stations and more efficient electric motors might be excessive, but we'd settle for radio masts with 100 times the range. ®