News Ossia Cota Home Can Wirelessly Charge Your Phone While It’s in Your Pocket

Olle P

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Apr 7, 2010
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What a crappy idea of a product! Nicola Tesla patented this idea in 1914.
The main problem is that the transfered energy drop quickly with the distance so the vast majority of the power sent out from the charger will be wasted.
A 1.0A USB charger provides 5W of power to the phone via cable.
Here a 3W omnidirectional transmitter would, at best, provide more like 0.001W of power to the phone (which is less than what it use when powered on).
To make the charger efficient it might be possible to use a variable aperture directional antenna, like the ones used in for example military radars, to send a narrow beam directly at each device. But then the price of the charger would end up at several thousand USD...
 
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TJ Hooker

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To make the charger efficient it might be possible to use a variable aperture directional antenna, like the ones used in for example military radars, to send a narrow beam directly at each device. But then the price of the charger would end up at several thousand USD...
Not really, you just need multiple antennas to form a phased array. Your home router probably already does this, referred to as beamforming.
 

Olle P

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... you just need multiple antennas to form a phased array. ... referred to as beamforming.
You think that's good enough to hit a ½" target at 5 yds with a minimum of spillover?

I've just read the whitepaper from Ossia and it didn't clarify anything.
The only deviation from Tom's atricle is that in the whitepaper they state 20W as the transmitter power and think 1W at the receiver is very good efficiency!
 

TJ Hooker

Glorious
Herald
The point I was trying to make was merely that creating an 'aim-able' directional antenna is practical even in cheap consumer hardware, e.g. beamforming in home wireless APs. I have no idea how tightly those sort of cheap consumer implementations are capable of aiming though. I agree that 5% efficiency sounds pretty bad.

Strangely enough, that whitepaper presents beamforming as a (poor) alternative to Cota, which implies that Cota uses some other method 'aim' its power. No details are provided on what that method is though. Also, they list Technovator as an example of RF beamforming, but from what I can find Technovator's solution uses near field resonant coupling, so not RF beamforming at all.

Unfortunately that "whitepaper" seems more like a promo piece than an actual technical document.
 

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