Introducing the Gizmag Store

Scavenging ambient electromagnetic energy to power small electronic devices

By

July 8, 2011

Manos Tentzeris holds a sensor (left) and an ultra-broadband spiral antenna for wearable e...

Manos Tentzeris holds a sensor (left) and an ultra-broadband spiral antenna for wearable energy-scavenging applications that were both printed on paper using inkjet technology (Image: Gary Meek)

Image Gallery (3 images)

As you sit there reading this story you're surrounded by electromagnetic energy transmitted from sources such as radio and television transmitters, mobile phone networks and satellite communications systems. Researchers from the Georgia Institute of Technology have created a device that is able to scavenge this ambient energy so it can be used to power small electronic devices such as networks of wireless sensors, microprocessors and communications chips.

Manos Tentzeris, a professor in the Georgia Tech School of Electrical and Computer Engineering, and his team used inkjet printing technology to combine sensors, antennas and energy scavenging capabilities on paper or flexible polymers. Presently, the team's scavenging technology can take advantage of frequencies from FM radio to radar, a range of 100 Mhz to 15 GHz or higher. The devices capture this energy, convert it from AC to DC, and then store it in capacitors and batteries.

"There is a large amount of electromagnetic energy all around us, but nobody has been able to tap into it," said Tentzeris. "We are using an ultra-wideband antenna that lets us exploit a variety of signals in different frequency ranges, giving us greatly increased power-gathering capability."

Manos Tentzeris displays an inkjet-printed rectifying antenna used to convert microwave en...

So far the team has been able to generate hundreds of milliwatts by harnessing the energy from TV bands. It is expected that multi-band systems would generate one milliwatt or more, which is enough to operate small electronic devices, including a variety of sensors and microprocessors. Tentzeris says exploiting a range of electromagnetic bands increases the dependability of energy scavenging devices as if one frequency range fades due to variations in usage, other frequencies can be used to pick up the slack.

The team is also looking at combining the energy scavenging technology with supercapacitors and cycled operation so that the energy builds up in a battery-like superconductor and is utilized once the required level is reached. The team expects this approach would be able to power devices requiring over 50 milliwatts.

The researchers have already successfully operated a temperature sensor using electromagnetic energy captured from a television station that was half a kilometer away. They are now preparing another demonstration in which a microprocessor-based microcontroller would be activated simply by holding it in the air.

Georgia Tech graduate student Rushi Vyas (front) holds a prototype energy-scavenging devic...

The researchers say the technology could also be used in tandem with other electricity generating technologies. For example, scavenged energy could assist a solar element to charge a battery during the day and then at night, scavenged energy would continue to increase the battery charge or would prevent discharging.

It could also be used as a form of system backup. If a battery failed completely, the scavenged energy device could allow the system to transmit a wireless signal while maintaining critical functions.

The Georgia Tech team believe that self-powered, wireless paper-based sensors will soon be widely available at very low cost, making then attractive for a range of applications, such as chemical, biological, heat and stress sensing for defense and industry; radio frequency identification (RFID) tagging for manufacturing and shipping, and monitoring tasks in many fields including communications and power usage.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag.   All articles by Darren Quick
19 Comments

My Physics teacher once told me about someone using a similar technologie in the early days of Radio. Because this was considered Stealing it was banned as illegal, as it influenced the range of the transmitter

Felix Bayer
8th July, 2011 @ 06:13 am PDT

At this rate we will soon tap into technology that Tesla understood to be possible 100 years ago. Strange that a man such as he could be left to wither and die without proper compensation and acknowledgement from the profiteers (and society in general) who so greedily used this man and then kicked him to the curb.

Muraculous
8th July, 2011 @ 07:26 am PDT

RCA already launched a similar product last year called Airnergy.

It can charge a mobile phone & has a USB port out for charging.

It has been commercially available since January 2010.

AB
8th July, 2011 @ 08:37 am PDT

Many years ago I discovered I could light up an LED by placing it behind a TV aerial in the loft of my parents house. Great I thought we could power all manner of things this way.

I was told when I researched it that there was a case of a man who had tried the very same thing and had been prosecuted for stealing electricity from the BBC. His antics had created a shadow of reduced signal behind his house and people had complained about no TV signal.

If it is possible to legally, scavenge EMR and turn it into a useable supply could I run some copper wire round the enclosure of the substation at the end of my garden and power the house from that, or put a load of TV aerials in the loft and light the house with LEDs?

MikeB
8th July, 2011 @ 09:18 am PDT

Tesla voluntarily gave up his claims to patent royalties owed to him by the Westinghouse company. It sucks, but he did do so of his own free will. Unfortunately, it came back to haunt him later when he didn't have the funds to complete all of his research.

Are all of you who asked about legality from the UK? I live in the US and have never heard of such a thing. I do know that it's illegal to decode signals that you're not paying for, i.e. satellite t.v. even though it's legal for them to bombard everyone with said radiation.

Daryl Sonnier
8th July, 2011 @ 09:45 pm PDT

Provided there is no specific Resonant tuning to a particular Transmitter frequency, field strength reduction [shadow-Mike B] should not be a problem.

The tendency to move from multi, non specific frequencies or ambient 'noise Rf' scavenging, to deliberate theft of those extra milliwatts is going to be a very difficult temptation to avoid.

Cosmic Rf radiation background noise harvesting would be good!

wrynic
8th July, 2011 @ 11:08 pm PDT

I am not that bright, but I thought that you couldn't convert a lower energy wave (IR) into a higher energy form (useful electricity). Doesn't that break the 2nd law of thermodynamics? Again, not that bright over here, but if someone could explain how this is NOT a perpetual motion machine (without being a troll, thank you) I would be interested to read it.

Gabe Cross
9th July, 2011 @ 11:40 am PDT

"The Georgia Tech team believe that self-powered, wireless paper-based sensors will soon be widely available at very low cost, making then attractive for a range of applications, such as chemical, biological, heat and stress sensing for defense and industry; radio frequency identification (RFID) tagging for manufacturing and shipping, and monitoring tasks in many fields including communications and power usage." ...excuse me but passive RFID tags have been doing EXACTLY what he's talking about for over 20 years! And yes, Tesla did it first. So how can they claim IP???

Daniel Beach
10th July, 2011 @ 05:40 am PDT

Firefly Technologies invented this harvesting technology in 2005 and was issued a US patent for a broadband wireless power supply. In 2006, the company sold their technology to Powercast, which received an award from the consumer electronics show for best emerging technology in 2007.

These guys better do some patent searching before they stake their claim in the wireless power arena as to who did what and when to avoid lawsuits.

justanothertechie
10th July, 2011 @ 07:26 pm PDT

This is the basic principles behind a crystal set. If you use a small rectifier circuit with a basic radio receiver, anyone can do this. Use a long antenna such as the guttering around your house :)

paulgo
10th July, 2011 @ 09:31 pm PDT

...use guttering it works, provided its not a modern house with PVC guttering !

Ken Munyard
11th July, 2011 @ 12:00 am PDT

@Daniel Beach:

.."excuse me but passive RFID tags have been doing EXACTLY what he's talking about for over 20 years"!

The article didn't mention PASSIVE RFID tags.

TexByrnes
11th July, 2011 @ 01:09 am PDT

"As you sit there reading this story you're surrounded by electromagnetic energy transmitted from sources such as radio and television transmitters, mobile phone networks and satellite communications systems."

This has been worrying me for some time now.....the vast increase in the incidence of various cancers must be due to some changing influence. One such is the introduction of a myriad of man-made electromagnetic signals to which we are all subject 24/7.

Am I alone in thinking that this bombardment may be a contributory factor?

Answers in black ink, for the users of 1960s Xerography please!

TexByrnes
11th July, 2011 @ 01:28 am PDT

I invented, or should I say reinvented the Ambient Power Module many years ago. You can see it at http://www.angelfire.com/ak5/energy21/ambientpower.htm

It's basically a voltage multiplier using germanium diodes.

Although this is work I did 30 years ago, I am still interested in this field. I think there is a way to increase the power transfer function to get more energy from a small antenna.

Feel free to contact me at joebtate@gmail.com

Joe Tate
11th July, 2011 @ 10:42 am PDT

If this harvesting of RF energy casts a shadow in the direction of the EM field then I can see this embedded or printed on clothing to reduce the waves penetration into the body.

Also, what the guy earlier was asking about violating the 2nd law of thermodynamics, they are not converting a lower form of energy to a higher form. Instead, they are harvesting ElectroMagnetic Wave energy across a broad spectrum which includes cellular, radio, and television sources. This energy is captured at the same value minus some lost as heat as it strikes the antenna's electron surface. Phonon activity, (atomic movement) has some influence on the losses involved when the energies make contact with the surface. As a result, they are capturing less energy than what is traveling through the air.

Gary Richardson
12th July, 2011 @ 04:50 pm PDT

"So far the team has been able to generate hundreds of milliwatts by harnessing the energy from TV bands. It is expected that multi-band systems would generate one milliwatt or more..." I think you meant hundreds of microwatts. That's believable. This isn't going to solve our energy problems, but it can reduce the necessity of power supplies or batteries in low-power systems. All you hand-wavers and philosophers, please do the math before you make outrageous claims.

http://en.wikipedia.org/wiki/Friis_transmission_equation

Then look up "precipitation static" to see how much DC you can get from a longwire antenna (be careful, it can be dangerous in a snowstorm!).

Captain Obvious
20th July, 2011 @ 09:57 am PDT

Way back in the dark ages when I attended school, I was told that if you mixed 2 frequencies together you observed the following:

F1

F2

F1 F2

F1-F2

and a DC component.

Hmmm. Wonder what the DC component was ?

Why it was the rectified voltage from the diode detector !

Hotshot
21st July, 2011 @ 04:07 pm PDT

The amount of power available seems to be so miniscule as to be hardly worth the bother. Surely easier to use a windup torch mechanism?

David Colton Clarke
21st February, 2013 @ 09:27 am PST
Post a Comment

Login with your gizmag account:

Or Login with Facebook:


Related Articles

Just enter your friends and your email address into the form below

For multiple addresses, separate each with a comma




Privacy is safe with us because we have a strict privacy policy.

Looking for something? Search our 26,500 articles