SPRAY-ON antennas waved about at Google's techfest
Turning the world into an aerial
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. ®
If you can boost the performance of an antenna by 100x by spraying this stuff on, then the antenna must have been at least 100x less efficient than a properly designed antenna in the first place. Maybe this stuff will help poorly designed and electrically small patch antennas but if you think it will make any kind of difference to radio/tv broadcast antennas or cellular antennas then you're wrong; these things are designed to operate with near 100% efficiency with very specific radiation patterns to optimise coverage, and applying any kind of coating will only be detrimental to the performance.
Antenna engineering is not a 'hit and miss' affair these days (to those who understand it) but an exacting science driven by the operators / broadcasters desire to squeeze every last drop of performance from their transmitters.
I have a couple of 15dBi gain antennas on my test masts outside; the path loss between them is around 30dB (in the UHF band). If I could spray this stuff on them and get 100x the range (an extra 20dB gain) then I'd get 10dB (10x) more power out of the receiving antenna than I put into the transmitting antenna and would be violating several laws of physics......
It's St Valentine's Day -- Not April 1st!
Either this guy is not telling us much about the details or most of it is bullshit. Maybe he's deliberately obfuscating what he's doing to deliberately mislead opponents (but then they'd recognize this from the BS).
!. Efficient antennas DO NOT get hot. Whip antennas on cars feel hot because the RF signals are absorbed into your hand, the metal itself isn't hot unless heat is generated by local RF absorption in some lossy/resistive material (your hand for instance) which in turn heats up the metal.
2. Metal antennas can be extremely low in loss. Loss (or I^2R losses) should NOT be confused with a low gain antenna. An antenna gets gain by being large -- having more elements. Essentially, hi-gain antennas don't give you something for nothing, all they do is point/beam/focus/concentrate the signals in a specific direction (i.e. send it where you want it to go).
3. There's nothing wrong the concept of spray-on capacitors that can be configured as an antenna. However, it won't work on metal surfaces and many surfaces are very lossy (i.e. absorb the RF before it's transmitted into space).
4. Transmitting 50MHz and above under lossy conductive salt water is fraught with problems (submarines use frequencies in the 10s of kHz and it's still marginal).
Reality check -- real facts and specifications please!
I call BS on this
ChamTech? More like ShamTech...
Will soon be sold next to those mobile phone "radiation protection" stickers.