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Cota system transmits power wirelessly at up to 30 feet


September 29, 2013

Hatem Zeine, the CEO of Ossia Incorporated and inventor of the Cota wireless charging syst...

Hatem Zeine, the CEO of Ossia Incorporated and inventor of the Cota wireless charging system, demonstrated charging of his smartphone during a presentation at Tech Crunch Disrupt 2013 (Photo: Ossia, Inc.)

Image Gallery (9 images)

In 2008, Gartner Research released a report in which it identified the number one IT grand challenge as "Never having to manually recharge devices." Physicist Hatem Zeine has invented what he believes to be the answer to this challenge. The Cota wireless power transmission system uses intelligently steered phased array antennas to focus a beam of microwaves on a receiver module – and only on that module. The inherently safe technology can deliver electrical power up to 30 feet from a central transmitter without any line-of-sight requirement and without interfering with other devices. The system is projected to hit the market in 2015.

At Tech Crunch Disrupt 2013, Hatem Zeine pulled the curtain on the Ossia, Inc. development company by introducing the Cota wireless power transmission system. The Cota technology uses steered phased array microwave antennas and the time-reversal properties of electromagnetic radiation to focus several watts of power on a wireless receiver while preventing any of the radiation to hit obstacles, resulting in an inherently safe charging system.

Cota uses a single microwave transmitter, operating in the 2.4 or 5.8 GHz industrial, scientific, and medical (ISM) bands that are also used by Wi-Fi routers. Unlike most wireless charging systems we've seen that require the close proximity between the transmitter and the device being charged, the Ossis transmitter will provide effective charging to distances of about 30 feet (9 m). This means that a single unit would suffice for most households and offices. The microwave power from the transmitter is directed onto charging receivers that convert the received power into a form that can be used to charge device batteries, or even to directly run portable devices.

The circuit board from the Cota wireless power receiver (Photo: Ossia, Inc.)

The charger is housed in an 18" cube while the receiver resides on a chip and uses a chip antenna for operation. The commercial version of the receiver will be small enough to fit inside a phone or even a AAA battery according to Zeine. The amount of electrical power that will initially be made available by a single receiver is expected to around 1 W (about a third the power transmitted via a USB socket), which is sufficient for charging multiple portable devices. However, the use of unmodulated RF power to transfer power does not seem to fall under any specific FCC regulation in the US. As Cota is not being used for telecommunication, the power which could be made available will be controlled by the general ISM regulations, which allow much larger power than the maximum one watt of a Wi-Fi router. Worldwide, of course, the limits will depend on local regulations.

The locator beacon signal in a room with no obstacles (Image: Ossia, Inc.)

The Cota system works by a clever combination of phased-array steering antennas on the transmitter and locator beacons on the receivers. In a room without obstacles, the RF radiation from the locator beacon (pulsed at 100 times/sec) travels directly from the receiver to the walls of the room. A portion of that radiation will strike the transmitter unit, whose electrically-steerable phased-array antennas (20,000 individually controlled antennas are being planned for the first commercial system) will not only detect the radiation, but also the direction from which it is arriving. This is similar in principle to the Lytro camera, which records the complete light field of a scene, rather than just the intensity of light at a particular surface.

The transmitter generates a time-reversed and much more powerful version of the locator be...

The transmitter then uses this information to fabricate a beam of microwave power that is focused only onto the receiver. This is accomplished by using a physical property of RF fields called time-reversal symmetry. If you reverse the beacon wave detected by the transmitter, it will follow the same path back to the receiver as it took on its way to the transmitter. As seen above, this means that the transmitter does not waste power heating the walls of the room, but rather makes nearly all of its output available at the charging receiver. Because of the rapid pulsing rate of the locator beacon, the transmitter is easily able to track the motion of the charging receiver (it is, after all, charging a portable device) as it moves around the room, and into adjoining rooms. The Cota system will charge your smartphone in your pocket as you wander around your house.

What happens if a person is standing in the room between the charging receiver and the Cota transmitter? An attempt to generate a direct microwave beam between the transmitter and the receiver would result in very little power transmission to the receiver, and quite a bit of microwave exposure for the person – not a good or safe situation. Fortunately, the property of time reversal symmetry saves the day.

The locator beacon signal in a room where a person is standing between the charging receiv...

As shown above, the locator beacon signal from the charging receiver again bounces around the room, but the portions that hit the person are absorbed and do not reach the Cota transmitter. (The power level of the beacon signal is too small to cause any biological damage, even with long exposures.) What does reach the transmitter's antennas are reflections of the beacon signal from the walls.

The time-reversed microwaves from the transmitter again focus on the receiver while avoidi...

When the time-reversed microwave transmission is generated, the radiation reverses course, bouncing off the walls in just the right manner to once again focus on the charging receiver, while missing the person in the room. (The person is subjected to a very small microwave exposure from diffuse scattering at the walls, but again this is at a very safe level.) Extensions of the same principle work for rooms containing multiple obstacles as well as multiple charging receivers (see photo gallery for examples). Owing to the way the Cota system harnesses the time-reversal symmetry of electromagnetic radiation, it is extremely flexible and intrinsically safe in use.

Ossia plans to license the technology to consumer electronics OEMs and ODMs for integration into consumer electronics products and the system could also be retrofitted to existing devices via an add-on dongle arrangement.

The potential of the Cota system for recharging and directly powering portable devices seems nearly unlimited. If these systems become a common feature of our everyday environment, in stores, offices, restaurants, cars, trains, and planes, the reliability and convenience of our portable connectivity will leap far beyond the current state of affairs. At a price point expected to be not terribly in excess of that of a Wi-Fi router, this could well be a dream that comes true.

Zeine demonstrates and discusses the prototype system in the video below.

Source: Ossia, Inc.

About the Author
Brian Dodson From an early age Brian wanted to become a scientist. He did, earning a Ph.D. in physics and embarking on an R&D career which has recently broken the 40th anniversary. What he didn't expect was that along the way he would become a patent agent, a rocket scientist, a gourmet cook, a biotech entrepreneur, an opera tenor and a science writer.   All articles by Brian Dodson


My kitchen bench is a mare's nest of chargers and cables.

29th September, 2013 @ 06:25 pm PDT

As it operates in the ISM band, they can use the same technology for data transmission. Use the carrier freq for power generation, and piggy back data.

The power transmitter would ideally be placed high, like in a light globe, to minimize obstructions.

I like the simplicity of listening for the highest beacon power and focusing the beam in that direction (in principle). I'm just curious how the device forms beams quick enough and accurately enough to adjust to the device's location, as multiple beams would have to work in unison.

ie - the array would have a pre-programmed matrix of which antenna must be on at what phase to aim the aggregate beam, but how accurate can this possibly be for a device this small.

One would assume the transmit array would have to be a bit bigger to achieve better accuracy.

29th September, 2013 @ 07:40 pm PDT

Brilliant! Wire a spare receiver to keep up charging supply for a "onesie" (long john) shaped electric blanket for interior wear and winter home heating is solved!

The Skud
29th September, 2013 @ 07:49 pm PDT

wow.. game changer /

Terry Hope
29th September, 2013 @ 11:02 pm PDT

And cooks popcorn too, or you're brain, whichever is closest. and with a power surge can set off a pacemaker.

Jay Finke
30th September, 2013 @ 09:24 am PDT

I hope they pick different freq. - like right now my wireless headphones interfere with my router. I have to use one or the other....

30th September, 2013 @ 09:49 am PDT

Good start. Now if they can only get rid of all the wires on components for stereo/video/computer peripherals, without frying everyone in the room, I'd be at the front of the line to buy the system. Whole house wireless! Brilliant. Don't think electricians would like it very much though.

30th September, 2013 @ 10:50 am PDT

Wattage is not a very useful metric without voltage. I guess we can assume 5V though because USB was used for the measurement. So this supplies 200mA then? That's pretty decent. To put it in perspective, an iPhone or Galaxy S charger is 1A. 200mA is not going to be able to sustain the charge on your device while it's in use, but it's enough to give you a decent bump while the thing is idle.

With that relatively low power output, I don't see this actually replacing standalone chargers. You can juice up an empty iPhone in an hour. This thing would probably take 4 or 5. Still awesome.

30th September, 2013 @ 11:26 am PDT

That first high energy beam would still hit the human though before it changes it's path.

Also once this becomes more powerful wouldn't that increases the hit redirect human ratio by a large factor!?!

Can someone answer these questions?

Benjamin Harrison Felts
30th September, 2013 @ 11:40 am PDT

Eventually this could replace all the wall sockets everywhere, and potentially even gas stations. What's the limit of wireless power transmission?

30th September, 2013 @ 12:56 pm PDT

@ Stradric. Wattage is fine, battery capacity can be stated in watt-hours so a 1 watt-hour battery would charge in an hour (without losses). If you turn it into voltage you'll then have to work out the field in Volts/meter then find out the receive antennas gain, aperture and impedance and then work it all back out to watts. So watts is best.

@ Benjamin. Damage from radio fields is a tissue heating issue so the time of exposure is as important as the field strength. A short term burst of 1 watt wouldn't damage you. Cell phones can put that out continuously and you hold them right up to your head.

30th September, 2013 @ 02:18 pm PDT

I can not believe that the microwave steering is accurate enough to charge a device in your pocket without frying you and there are already ways to charge multiple devices without having to fit the connections or have a pile of tangled wires.

30th September, 2013 @ 03:35 pm PDT

Yeah, so Tesla invented this like 100 years ago.

John Moore
30th September, 2013 @ 04:22 pm PDT

Cool product but i think, these guys are Spanish trials motorcycle fans

I already have a Cota 348 and 349 . . wouldn't mind one of the newer ones tho

30th September, 2013 @ 04:47 pm PDT

Awesome tech, But why have a tech conference, get the man behind it all on stage, then throw a time limit on him!!!!! Do you NOT want answers!?!?

Also, He lost a little authenticity when talking about the power loss. With a wall out let you're getting like 99% efficiency, not 50% like he said. and his device gives you 15% efficiency, I'm fine with a smaller number because of the added convenience, but not this much. My electricity bill in already pretty high, I don't want to pay for power that is "lost in space".

Derek Howe
30th September, 2013 @ 05:59 pm PDT

"The Cota technology uses steered phased array microwave antennas and the time-reversal properties of electromagnetic radiation to focus several watts of power on a wireless receiver"...... time-reversal properties???

Simon Sammut
30th September, 2013 @ 07:33 pm PDT

Benjamin and Jay, you haven't quite grasped the technology. The charging beam would never hit you. the locating beam from the device to the charger would be minuscule - that is what would be blocked by your body. the charging beam would be following the unobstructed locating beam back to the device via reflecting surfaces, or direct line of sight only if that was unobstructed. The point is that only reflecting surfaces would bounce the locator beam to the charger. Reflecting, not absorbing. So the charging beam would only ever follow reflecting surfaces back to the device. This is what is meant by intrinsically safe.

1st October, 2013 @ 12:08 am PDT

warren52nz no the issue is NOT tissue heating. it is interference with ion channels on axons.

Walt Stawicki
1st October, 2013 @ 12:58 am PDT

The technology is inherently safe. People commenting here who don't understand that should pay closer attention.

2nd October, 2013 @ 06:17 am PDT

There's too much pseudo-science here. I wouldn't bet my life's savings on this ever becomming a commercial product...

24th October, 2013 @ 03:18 am PDT

Wow N Tesla was lighting electric light bulbs from miles away 120+ yrs ago and we think this is special Why?? Yes I do like the fact they are pursuing this tech, but we should be so much farther along IF the oil/utility robber barons had not suppressed these inventions, all so we would be dependent upon fossil fuels etc.

The US Patent office has stated that any "Free Energy" Generator/Collector/Magnifier devices that work are passed to the Dept of Defense who then suppress it. Thorium Batteries, Water Cars, Magnetic Gens etc etc I could go on for ages

24th October, 2013 @ 04:22 pm PDT
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