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Fractal Antennas more efficient?
Mike Hicks writes "Scientific American has a short article talking about fractal antennas. They can be 25% more efficient when used in place of the stubby antennas on cellular phones. An antenna that's fun to look at -- who'd a thunk it? "
They already can monitor any cell phone conversation and triangulate position in less than five minutes anyway.
You mean it is possible to do this, but of course it is not legal to do this. That doesn't mean it doesn't happen and it doesn't mean you should blindly accept it!
most people are unbelievably boring.
How do you know? Have you been listening? I think maybe you have.
It is simply not practical... for the government to monitor over 270,000 people.
Really? Sounds simple to me. Do you know this is not possible? Most of the system is almost there now. If it was all automated then why not. How do you think all those people get their bill and should we accept it?
Don't give them a reason to watch you, and they won't.
That is really funny! I guess your one of those people who think that if you are truly innocent you wont be convicted. Have fun with your rude awakening.
Why don't you go to the EFFs web page a look around at what has been happening for the last few decades.
www.eff.org
Linux is only free if your time has no value. Windows is only free if you threaten to use Linux.
I forgot the effects of reflected signals. With the kind of precise timing those things need, that would obviously be a problem.
Dammit, I wish there was some easy way to get good reception without making the unit huge. My friend has a 12 channel Garmin with a fairly large detachable antenna, and it constantly loses satelites.
My unattainable dream is to have only one unit i ever take anywhere. Something like a combo cellphone, pilot, gps. Ahhhhhhh.
Vidi, Vici, Veni
Know where I would really like to see these? GPS receivers. Those could use all the reception technology they can get. Anyone know if there are any plans to include this in a handheld GPS receiver? If so, where do I sign? :-)
Vidi, Vici, Veni
If that's what you're worried about, then I hope you sit at least 4 feet away from your monitor/hard drive/motherboard/microwave oven. Radiation is everywhere, and humans/raccoons/lizards/bacteria have evolved DNA repair mechanisms to compensate for that over the years. (To say nothing of even more highly damaging things like UV--better stay inside while you're talking on that cellphone!)
ANyway, this bit about small antennae is probably a good thing. The real problem that I can see is that smaller and smaller cellphones will eventually lead to cellphones being implanted into peoples' bodies. Think about it... microphone implanted under the jaw, speaker stuck in one ear, and the ever-tinier electronics package put wherever you want it. (Why carry around a StarTac when you have the entire system internally?)
This might not be accepted at first, but it might catch on. And if it had a GPS system as well... Big Brother knows exactly where you are at all times. Gulp.
Give a monkey a brain and he'll swear he's the center of the universe.
If a fractal antenna works more efficently.. wouldn't a Pyrimid who's 4 sides consisted of the fractal designed antenna work even more efficently in all directions? The way the atenna is now.. it would function like that in a directional finder.. where when the side of the atenna is pointing to the transmitter or receiver.. the signal would be weak.. and when the broadside is facing.. it would be strong. By making it more of either a 3 or 4 sided pyrimid.. you'd have more surface area receiving the signal at one time.. allowing for a better reception at all sides and therefor a longer distance of receiving a clear(er) signal.
Ron Rossman
rjr162@psu.edu
UGrad Student in the College of Engineering
Penn State University
I talked to a friend/collegue here at work, and here is what he said:
.. far too big and battery hungry for a handset using todays technology. Mobiles in any case require 360 degree coverage .. you can have a handset lying down standing up, in any orientation you like relative to the RBS (base station)
...(or your head) ... not smart and you would loose MANY dB ... most of the power. which removes
... IF we were using very very high frequencies. But a practical
" As is common in the US, companies sometimes make a big noise about stuff that has been known for (almost) forever. As even mentioned in the article, random and regular layouts are both tradidtional for phased array antennas,
but other layouts are also used and their characteristics are known.
However there are a number of HUGE problems before you can bury such an antenna in a handset as they suggest tand the (prototype) phone shows.
1) array antennas only effectively transmit at 90 degree to the surface. If you add it some electrical tilt this can be extended to approx a 45 to (extreme) 60 degree eitehr side of that but the circuitry to do that dynamically is VERY complex
2) That energy would need to go through your hand
the point
3) actually you can't build a phased array that small in any case, the article is just "science fiction" in the sense that it is theoretically possible
problem is that you can't have the elements of the array signigicantly closer together than a wavelength, otherwise they just couple togetherand dont act independently (and the array therefore stops functioning as an array, it just works as one antenna). a 900 MHzsignal has approx a 30cm wavelenth.
So that's that!
An antenna radiates some (or most) of its energy, and sends the rest back toward the radio. This ratio is what we call SWR. Of the returned energy, some might be lost in the feedline. The rest reaches the radio and bouces back to the antenna for "another try".
If we have feedlines that are relatively long for the frequency, we get concerned about the SWR so that our energy is not wasted heating up the coax between the radio and the antenna. If our feedline is short, then the SWR is a factor if it raises the voltage high enough that the reflected energy bothers the radio. That can be really exciting if you are looking at hundreds of watts, but should not be a factor with the low power levels we are contemplating here.
So if our feedline is short enough, as is common with handheld radios (and cellular phones are radios, of course), our antenna is going to be radiating nearly 100% of the power. It is like the "efficiency" of an electric heater - an electric heater is ALWAYS 100% efficient.
Perhaps the authors really mean that their antennas can direct the radio energy in a more useful direction, such as horizontally. Often this is exactly what we want, and we already have antennas made just for this (such as a vertical dipole). If this is what they are getting at, I did not see this in their report.
A dingo ate my sig...
If so, one could easily use a laser printer to print a fractal of their choice onto that blue press n' peel material, iron it onto a copper board, etch away, and have a highly detailed fractal antenna for cheap.
Might be something worth trying.
Yeah, well, "sort of". There are three "media" to consider - the output stage of the transmitter, the feedline to the antenna, and the antenna itself. Standing Waves (the S W in SWR) are caused by an impedance mismatch at these transition points. Thus, not all of the energy the transmitter generates actually gets to the antenna to be squirted into the ether. Energy "lost" in the transmission line is just good old "ohms law" losses caused by electrical resistance.
This gets worse as the frequency gets higher - caused by the "skin effect" - only the outer part of the wire (or whatever) carries the electrical energy.
The other thing about antenna efficiency is that the antenna itself cannot increase energy - efficency of so called "gain" antannas is generally because they focus the transmitted energy in a particular direction, rather than spreading it equally in all directions.
What the antenna mey be able to do, with the great number of radiating elements, is effectively transmit with a mixed polarisation - so when the signal bounces around (line most cell phones signals do) there is still sufficient component with a polarisation that matches the antenna at the other end.
Still, an interesting concept. Ken