Scottish brainiacs erect wee super-antenna A spinout from Edinburgh University is touting a mobile-phone antenna smart enough to aim at the nearest base station, and small enough to squeeze into the slimmest smartphone. The technology was developed at Edinburgh University by a trio including one professor and a PhD student, backed with £450,000 from the Scottish …
Seems sensible enough - it's just an automated directional antenna.
More interesting applications would surely be outside the range of phones - such as the stated WiFi example, Bluetooth, GPS, etc.
But I can't help thinking this is something that is just a miniaturisation of something already existing, say, satellite tracking antennas, etc.
License it direct to those manufacturers, let them slap it into their dies, and it'll be on £2 Bluetooth chips before you know it. Methinks patent licensing would actually be the thing that kills it, though, if anything - not battery life.
I thought that, isn't it the same sort of idea as synthetic aperture sonar? You have an array of weaker transmitters and arrange the emitted signals so that they'll constructively reinforce in one direction only. The actual wave physics isn't too complicated.
I think the impressive/novel bit is that it's been miniaturised so much; it'll have to have multiple aerials capable of receiving and discriminating- accurately- multiple signals that are about 14cm long (wavelength at UMTS receive of 2110MHz).
It's tiny, and it's the difference in volume between this antenna and a normal one that counts (not the absolute size).
I'd struggle to see how it can't improve overall battery life, unless it doesn't work as advertised, or if the power budget for the antenna is negligible compared to the total demand. I know the screen is the biggy, but that's not operating most of the time.
The cell antenna in most phones I know is not on the PCB at all, but wrapped around something else, for example the resonating cavity for the loudspeaker. In effect, no otherwise available volume at all is taken up by it. Ergo, there's no battery capacity to be gained by its deletion thus any improvement in antenna efficiency results in a longer talk time or reduced overall volume. Both worthwhile pursuits.
My thoughts are you'll need at least two in the phone to cope with handover between cells - possibly more. For starters, when you're locked on a particular tower you are also taking measurements of your surroundings to see if any other cell is getting better than the one you are on. How is this achieved with a single directional antenna?
It gets worse in UMTS with soft handover meaning you are supposed to be Tx/Rx to multiple cells at the same time. Also, can the directional connection you are on fade out when a regular "omni" would have merely listened to a different path - might lead to an increase in call drops if you don't plan around that (so perhaps need both).
I could see it being used to enhance the current receivers/transmitters by getting a better signal quality on an existing connection, though
"My thoughts are you'll need at least two in the phone to cope with handover between cells - possibly more. For starters, when you're locked on a particular tower you are also taking measurements of your surroundings to see if any other cell is getting better than the one you are on. How is this achieved with a single directional antenna?"
Depends how quickly it can swap to checking around and back again whilst you're using it. My CPU has only six cores, but it is running way more than six processes. In between me typing each character in this post it carries out a million other actions. If the antenna only has to interrupt for 1ms every 5 seconds during a call to see if there's a better antenna to use, you still only need one.
Note, I don't know much about antenna design, I'm just illustrating that it might be fine.
No, you don't need multiple antenna to do this - or rather, you do, but you need multiple antenna to do beamforming anyway.
Beamforming works by having many antenna (the more the merrier), each being fed with a slightly different signal (or in the case of receiving, each feeding the receiver with a slightly different signal). The signals are modified in phase and amplitude such that the signals add in the direction you want the signal to go, and cancel in all other directions. (for receive, you delay the signals from the different antenna and attenuate them differently).
To handle multiple beams, you have multiple sets of delay&sum hardware, fed by all the antenna - each set of delay&sum creates a different beam. So if you want to have one beam for the active tower, one beam for the next candidate tower, and one omnidirectional receive to handle scanning, you have three sets of delay&sum hardware, all driven by the same set of antenna.
Re increasing battery life, or not: It's the milliwatts needed to power the computation versus the milliwatts saved with respect to a conventional antenna. It may cost more to compute than it saves in transmission, much as a better compression algorithm may save less on transmit time (or cost) than it costs you in CPU time (or electricity).
For some reason I'm reminded of Vinge's "zones of thought" SF universe.
It almost certainly is a 'pico switch'. You can't make antennas that small work properly at these frequencies, the cable or circuitry feeding it would resonate more....
Also there would have to be more than one antenna to effect any kind of beam steering. I'd be very surprised, given the small amount of space in a mobile phone, if this would be any more effective than just having a decent ordinary antenna in there in the first place.
Not directly the subject of the article, but they mentioned it... I have a Bluetooth headset (like many of us) and I typically have my phone in a hip pocket while I use it. Are they telling me that this is less efficient than having the phone in the same horizontal plane as the headset itself? I had always assumed that the phone used a different transmitter / receiver for bluetooth than for the actual phone calls. If this is the case, why would it be designed to transmit in the horizontal rather than the vertical? No-one walks around with their headset on holding the phone up at the same height as it. Or is my assumption that Bluetooth and the normal phone signal use different transmitters incorrect? Can anyone explain?
The link from your headset to your phone is not the issue - that is a trivial connection, as you are only looking at a meter of distance, if that (unless you are a giraffe).
It's the link from your phone to the tower. Your phone was designed to radiate horizontally, assuming you are holding it more-or-less upright to your ear. If it is in your pocket, from an orientation standpoint, it's the same as being at your ear (unless your phone is small, your pocket is big, and your phone is sideways in your pocket.).
However, you are a very efficient absorber of radio signals, so having your phone in your pocket means that roughly half the signal is not going anywhere. If you are looking for the absolute best connection to the tower, take your phone out, and hold it above your head (and no, I am not trolling). However, the difference between in pocket, at ear, and above head isn't very much, and unless you are right at the margins, isn't worth worrying about.
Thanks for the informative response. I guess my main surprise was that Bluetooth and the normal phone signal are using the same antenna. But I realize now I was probably confusing the antenna with the Thing That Is Connected To The Antenna That I Don't Know The Name Of. Probably there are two chips working at different frequencies, but they share the bit of wire that is the actual antenna and it's this latter of course that is relevant for direction. Makes sense, now!
Not sure I like being called a very "effificent absorber of radio signals", though. Makes me sound a bit fat. : (
Not sure I like being called a very "effificent absorber of radio signals", though. Makes me sound a bit fat. : (
It's the conductive (watery) bits of you that are the good absorbers. Adipose tissue is unlikely to be a major contributor to absorbtion of microwaves!
Popular with ABM early warning radars but not really practical on mobile phones until now
Perhaps.
Clever stuff is that the elements (there would have to be at *least* two) are optimizing transmission signal for both *gross* movement (you in vehicle with phone on) and *attitude* (switch to headset and put phone in side pocket for example). One might be *relatively* slow, the other fairly fast. Tapping the phones accelerometer/magnetic compass/whatever might help here. It's the *rate* at which the settings have to be calculated and changed (for the power budget) that makes it a bit of a b***er.
As others have pointed out a *lot* hinges on weather the power saved in transmission is > power used to compute power/phase of transmitting elements *and* does it need additional controller chips, or is it licensible IP you can include on your master controller chip or software that runs on its CPU.
Yes.
Until a bug replaces a plus by a minus, and the beam is directed straight at your head, and then the phone ramps up the power so a sufficient wattage emerges from the other side of your head.
So if the battery life suddenly drops by a factor of maybe 100 and/or the reception suddenly goes cr*p, you have been warned. It's trying to kill you.
I think it refers to the gears on the face of the 2 pound coin. Why it's on the picture is an entirely different matter. It could be that there is some Scottish academic that is still miffed with the mechanical impossibility of the design on it, but I'm not sure that would explain the interesting grammar (interesting because of the lack of it, mostly).
Whatever happened to amanfromMars, anyhow? Haven't seen him around these parts for some time.
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