California company gets FCC approval for at-a-distance device charging

California company gets FCC approval for at-a-distance device charging
Credit: Energous

Energous, a San Jose, Calif., company, is the first firm to receive federal approval for a wireless charging system purported to power devices from up to 3 feet away, the company said.

The Federal Communications Commission certified the company's "WattUp Mid Field transmitter," which uses radio frequency energy to deliver power from the transmitter to a multitude of device types, Energous said.

"The certification marks a significant milestone for the industry and paves the way for future wireless charging ubiquity for nearly any small electronic device, including smartphones, tablets, fitness trackers, smart watches, earbuds, wireless keyboards and mice, smart speakers and more," Energous said.

Energous' system is different from the "resonant induction" technology behind the Pi wireless-charging system, and provides a longer range than chargers from Belkin and Mophie that require contact with a device, Engadget reported, adding that devices to be charged must be equipped with a receiver.

WattUp isn't ready for retail yet, but Energous will demonstrate the system at the Consumer Electronics Show in Las Vegas in January, Engadget reported.

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Dec 29, 2017
The device appears to use 5.8 GHz radio transmission to transmit the power, and the only way it can maintain any efficiency is by having a highly directional beam, which means it must be transmitting very small amounts of power to not exceed SAR limitations for objects and people crossing the beam.

5.8 GHz radio waves are readily absorbed by many things, including the human body. Getting most of the power over to 15 ft away would require such a tight beam that transmitting significant amounts of power would turn it into a microwave lance capable of burning blisters onto your skin.

Dec 29, 2017
The progressive power for free crowd will just love this. Yet they will bemoan the emissions from AC power transmission lines.

Dec 29, 2017
How did the far-field device pass the OET 65 recommendations from the FCC? How are they not heating people with RF?

Dec 29, 2017
Radiowaves are misnomer - the 5.8 GHz is rather close to microwave oven frequency range

Microwaves ARE radio waves. The name just refers to the range of frequencies between 300 MHz - 300 GHz. UHF television broadcasts fall within this range.

The radiation in this range is not resonant for water molecules

It doesn't need to be. It still gets absorbed within millimeters due to dielectric loss. For 2.45 GHz most of the energy is absorbed within 2 centimeters.


The reason why the effect is rather weak in free air is because of the impedance mismatch between your body and the surrounding air, which causes a large part of the energy to reflect. A microwave oven forms a resonant cavity where the reflected energy returns back to the item being heated, so the energy gets absorbed in multiple passes.

Still, if you stood in front of a pencil-thin 100 Watt beam at 5.8 GHz, you'd definitely feel a burn.

Dec 29, 2017
Household MW ovens use 2450 MHZ which happens to be the center of the 2.4 GHZ Wi-Fi band. 5800 MHZ is at the upper end of the 5.8 GHZ Wi-Fi band.

I would suppose that both are equally destructive to human tissue.

I know that microwaves are known to create cataracts in eyes. That can't be good long term.

Dec 29, 2017
Here's a really old film to explain visually what happens when a wave encounters a discontinuity in the propagating media:


Dec 29, 2017
Not that it matters to the discussion but TV occupies 54 MHZ to about 800 MHZ with other stuff in the middle including the FM radio band.

Dec 29, 2017
Solidly in the middle of my I wonder department is when do electronic oscillators begin to emit photons. Infrared begins at say 1x10^13 and terahertz oscillators start at 1x10^11 which is not really that far away.

Dec 29, 2017
Not that it matters to the discussion but TV occupies 54 MHZ to about 800 MHZ

It is tangential, because the higher up you go in frequency, the shorter the wavelenght, and the smaller the objects which refect the radio wave. At the higher end, the transmission starts to require a clean line of sight, forming shadows behind objects like trees or buildings, which is why things like cellphone towers can't use arbitrarily high frequencies to transmit more data. Instead, they must use elaborate coding and modulation schemes to increase the sensitivity, to make them more immune to noise on the channel and increase the amount of information which can be transmitted within a single wave cycle. The digitization of TV frees lower frequencies like 700 MHz for data transmissions, giving greater coverage.

Power transmission at high frequencies suffers from the same flaw, but there, increasing the sensitivity does not increase the amount of energy reaching the reciever.

Dec 29, 2017
when do electronic oscillators begin to emit photons

They never stop. Even a simple CB radio transmission, or waving a charged rod with your hand, can be understood as emission of photons as the EM influence spreads through space, but the "size" of such photons, or the space that the peak of their probability distribution occupies, is very large. The photon is smeared far and wide.

The explaination supercedes my understanding of QM, but my personal simplification of the issue is that at these large scales what you observe as being classical waves which spread around, is directly the probability wave of the photon. I am likely to be wrong.

Dec 29, 2017
Well thanks for the enlightenment even if it is not 1000% correct.

Dec 29, 2017
Solidly in the middle of my I wonder department is when do electronic oscillators begin to emit photons. Infrared begins at say 1x10^13 and terahertz oscillators start at 1x10^11 which is not really that far away.

An answer:


We should start with the obligatory warning that a beam of EM radiation is not a swarm of photons. See What is the relation between electromagnetic wave and photon? for more on this.

With that out out of the way, there is no lower limit on the energy of a photon. Radio waves of arbitrarily low frequencies still gain and lose energy in units of one photon i.e. hν

In essence, if you could transmit little enough energy at say, 43 MHz for a radio controlled toy car, and absorb that energy somewhere, it would behave as if you had emitted a single photon that didn't radiate everywhere around but instead went from your transmitter to your reciever.

Dec 29, 2017
Obviously then, the lower the frequency, the smaller the energy of a single photon, and so any practical transmitter would emit a myriad of photons for each wave cycle, so for all observers around the transmitter, there are enough of these wave-particles to recieve as if there was a classical continuous wave being emitted.

Yet each of them is a single photon, yet each of them can be recieved by any of the observers around as their wavefunction may collapse anywhere, so it is the spread of the wavefunction of the photon(s) that appears as the propagating wavefront.

That might be a more correct understanding of the matter.

Dec 30, 2017

Those articles appear to be a year old. They have FCC approval now. So what changed?

Dec 30, 2017
100 Watt in pencil-thin beam is essentially an unfocused laser

Not if it isn't coherent.

Bellow this wavelength the photons get another quantum wave and they change into subluminal particles

No they don't.There's no such discontinuity in the equations at any particular wavelenght..

Dec 30, 2017
Those articles appear to be a year old. They have FCC approval now. So what changed?

Bigger phased array with a wider beam, lower efficiency, less power. All those means can be used to reduce the power density.

Mind, a phone will appear to be "charging" even if it gets a few milliamps of current. It just takes forever to fill up. For small devices like bluetooth keyboards and cordless mice, it may provide enough power - for a laptop, forget about it.

Consider that you have a tablet computer on your desk, it has a 10 Wh battery inside, and the wireless reciever can pick up 10% of the radio beam at that distance. To get it to charge in a reasonable time, the beam power must exceed 100 Watts.

Dec 30, 2017
Also, for low powered devices such as a mouse or keyboard some solar cells would work just as well.

Dec 30, 2017
Another fact to consider is wasted spectrum. Do we really want to clutter a part of the WiFi band with relatively high power transmitters for such a trivial application? Could you imagine the interference that would result if 20 families in a 100 family apartment building were using this device. A WiFi router puts out about 1/2 watt max. This device would swamp many channels on each side of it's transmitting frequency. It is just as easy to power local devices with resonant coils and skip the microwave pollution.

Dec 30, 2017

Those articles appear to be a year old. They have FCC approval now. So what changed?

New FCC chairman, the same one who cancelled net neutrality. Business first, people second.

Dec 30, 2017
Ironhorse the internet was built by private industry and functioned very well without net neutrality. When there is a provable problem then you can pass a law. Under net neutrality users and companies that do not use a lot of data would wind up subsidising those who do. A fast lane and a slow lane are a real necessity since some data is time sensitive and some is not. If you are browsing a web page or downloading a movie for later viewing a delay of a few seconds here and a few seconds there is no big deal. If you are running a VOIP or teleconferencing application you need priority service and it is only fair that you pay more for that. BTW there is a difference between internet speeds and the amount of delay between individual packets.

That being said one carrier should not be allowed to purposely slow down the delivery of a competitors packets and if a carrier advertises an unlimited data plan for a set fee it should not be allowed to throttle back a users internet speed.

Dec 31, 2017
LOL, from when the properties of Universe are controlled by simplistic equations invented by people

Those equations describe observable reality, as far as it is observed to exist. If you have a beef with it, provide your own equations, and also the emprical evidence that supports your assertion that they do describe reality.

Otherwise, talk is talk.

BTW It's not discontinuity but a smooth transition.

No such transition is supported by any credible theory of QM.

Dec 31, 2017
These equations were derived for abstract flat vacuum - not for real vacuum filled by ZPE/CMB noise

If you can formulate a theory - a set of equations that include this phenomenon of double wavefunctions and "subluminal particles", then please do. As far as I see, you have no such thing. A theory is not just saying things, it's a rigorous description of -how- things are happening, which can then be tested to verify it.

It's easy to pull shit out of your ass and claim the mainstream science is wrong. It's a whole other thing to come up with an actual competitor to it, because it has to be falsifiable to count as science.

Jan 01, 2018
The purpose of this device is not to remotely charge cell phones and the like but to remotely remove money from ignorant unsuspecting investors.

Jan 02, 2018
The focusing of heat doesn't care about coherence, just about Watts/area

But laser light does care about coherence. That's the point of it, and the reason why laser light can be focused so uniformly.

but in contemporary physics many important findings are dismissed and ignored, because they have no rigorous theory yet

As it should, because without a rigorous theory, all you have is some assertions pulled out of a hat. You don't have a description of what happens, you're just saying words, so nobody can evaluate your claim in any reasonable way.

Another ideas are non-critically accepted, because they have math developed already (stringy, susy, loopy), despite this math doesn't allow any testable predictions and these ideas have no practical usage.

These hypotheses are not non-critically accepted, exactly because they offer no testable predictions. You're just confusing pop TV-Science with science.

Jan 02, 2018
many important findings are dismissed and ignored, because they have no rigorous theory yet (cold fusion, antigravity, room temperature superconductivity etc.)

Those aren't ignored because they lack a rigorous theory, but because they lack a replicable -finding-

The dispute is about observing and isolating the effect in the first place, before any attempt at explaining it. Those things are stuck at the empirical proof of an event or phenomenon, and demanding people to take all sorts of conjectures about them seriously is like demanding people to take your hypothesis about angels dancing on the head of a pin seriously: first provide the angel.

Science goes two ways: from the empirical to the theoretical, and from the theoretical to the empirical. Both ways have their own requirements: a theory should have testable consequences, and a test should have replicable results.

Otherwise you can never know whether you're describing or observing reality at all.

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