Student Invention May Significantly Extend Mobile Device Battery Life

imamac writes with this excerpt from news out of Carleton University: "Atif Shamim, an electronics PhD student at Carleton University, has built a prototype that extends the battery life of portable gadgets such as the iPhone and BlackBerry, by getting rid of all the wires used to connect the electronic circuits with the antenna. ... The invention involves a packaging technique to connect the antenna with the circuits via a wireless connection between a micro-antenna embedded within the circuits on the chip. 'This has not been tried before — that the circuits are connected to the antenna wirelessly. They've been connected through wires and a bunch of other components. That's where the power gets lost,' Mr. Shamim said." The story's headline claims the breakthrough can extend battery life by up to 12 times, but that seems to be a misinterpretation of Shamim's claim that his method reduces the power required to operate the antenna by a factor of about 12; 3.3 mW down from 38 mW. The research paper (PDF) is available at the Microwave Journal. imamac adds, "Unlike many of the breakthroughs we read about here and elsewhere, this seems like it has a very high probability of market acceptance and actual implementation."

Counter-intuitive!

[4D6963]

Wow, is it me or does it feel profoundly counter-intuitive that you'd lose more power over the wire than over radio waves?

What?

[Anonymous Coward]

The explanation given on the website is very poor. The resistance of the wires connecting the transceiver and the antenna is low and little power is lost in them.

In addition, they quote him as saying "There are so many applications in the iPhone, itâ(TM)s like a power-sucking machine" but what they're talking about is the power lost at the antenna and not from the processor which is what he implies. Therefore it wouldn't do anything to prolong battery life when using non-transmitting applications.

Perhaps this is a case of announcing something without giving away what it really is or perhaps pathetic technology journalism?

How about that inverse-square law?

[Anonymous Coward]

From the research paper: [mwjournal.com]

The conventional LTCC package provides 3 times more range
than the proposed design but consumes 12 times more power.

So you save power versus the conventional design, but you lose range.

To provide the same signal strength at triple the range, you need to broadcast 9 times as much power. To broadcast 9 times as much power with an equally compact transmitter, is it surprising that you need to spend 12 times as much power due to size/efficiency trade-offs?

This doesn't sound like an advance at all.

Re:Counter-intuitive!

[Plekto]

They use wireless just fine with mics and pickups and so on on stage for these reasons all the time. Less cables, less problems, and also if you've ever had to deal with grounding issues, wireless or a line-level signal that's amplified at the source is a huge improvement. I suspect that's the real problem here - too much background RF noise from the components. Rather than brute-forcing it, he decided to find a way to get around this and clean up the signal in the process.

Btw, most pros don't use wired mics any more. Too many issues. Most studios don't use non-powered speakers any more, either. You're right - I haven't found many setups that use IR or wireless(yet), but I can find many professional systems that use S/PDIF, optical, or other non-analog transmission methods.(shoot, most home theater interconnects are now HDMI for exactly these sorts of reasons.

Re:Counter-intuitive!

[Anonymous Coward]

Dude...speaking as an RF Engineer, I think you should just declare yourself as "officially mentally retarded"...

Re:Counter-intuitive!

[thebes]

Umm, dude...just because you shield a component doesn't mean it stops radiating. Shielding inhibits EM fields which are already present. To reduced radiated losses, you need to either improve the fundamental design of the circuit or make it radiate so well that you build an antenna instead.

Student?

[tyrione]

What a horribly misleading title.

Ph.d candidate... is factual and much less sensationalized.

Re:But what % of battery use does it represent?

[morgan_greywolf]

Or use a Web browser. Phones typically communicate with the Internet through the cellphone network over the two-way radio. This might improve WiFi phones, too, as WiFi also (obviously) employs a (much lower-power) two-way radio.

Re:How about that inverse-square law?

[Jott42]

You can not get any gain in an on-chip antenna at this frequencies: it is to small. He is comparing the use of only an on-chip antenna, which is never used in mobile phones, with the use of a coupled external, somewhat bigger, antenna on a ceramic substrate. Not at all suprising that he gets a better performance with the latter, as it is bigger. He would get even better performance with a classic mobile phone antenna, though.

I.e. This will not revolutionize the battery life of your iPhone or Blackberry. The losses in the coupling between the integrated PA and the antenna are very small (if we disregard detuning due to human proximity effects. Which is another story, and which is not influenced at all by the design in question.)

The comparison between two different antennas at different powers is not very good science - it is somewhat suprising it got published. (But it is only at a small conference, so it is not that surprising.)

Re:Xzibit

[4D6963]

OMG and you put a 200 lb 10,000 W speaker in my telephone so I can make anyone temporarily deaf in a radius of 30 feet when I receive a text message!! Thank you Xzibit!!!