News / Science & Technology

Device Turns Stray Microwaves into Energy

This five-cell metamaterial array developed by Duke engineers converts stray microwave energy, as from a WiFi hub, into more than 7 volts of electricity with an efficiency of 36.8 percent—comparable to a solar cell. (Duke)
This five-cell metamaterial array developed by Duke engineers converts stray microwave energy, as from a WiFi hub, into more than 7 volts of electricity with an efficiency of 36.8 percent—comparable to a solar cell. (Duke)

Related Articles

Study: Solar Panels Rock Out to Pop Music

Pop music causes vibrations in solar cells that increase their efficiency by up to 40 percent

Algae Could Fuel Cleaner Road to Future

California company patents its algae-oil technology
VOA News
Scientists have built a device they say can capture stray microwave signals and convert them into electrical power capable of recharging a cell phone or other small electronic device.

Researchers at Duke University’s Pratt School of Engineering in North Carolina say the device is similar to a solar panel and has a similar efficiency, and while it harvests microwaves, the researchers think the harvester could be tuned to harvest the signal from other energy sources, including satellite signals, sound signals or Wi-Fi signals.

The harvester uses something called “metamaterials,” which are “engineered structures that can capture various forms of wave energy and tune them for useful applications.”

“Until now, a lot of work with metamaterials has been theoretical,” said graduate student Alexander Katko. “We are showing that with a little work, these materials can be useful for consumer applications.”

Researchers used a series of five fiberglass and copper energy conductors wired together on a circuit board to convert microwaves into 7.3V of electricity. By comparison, Universal Serial Bus (USB) chargers for small electronic devices provide about 5V.

“We were aiming for the highest energy efficiency we could achieve,” said engineering student Allen Hawkes. “We had been getting energy efficiency around 6 to 10 percent, but with this design we were able to dramatically improve energy conversion to 37 percent, which is comparable to what is achieved in solar cells.”

With additional modifications, the researchers said the power-harvesting metamaterial could potentially be built into a cell phone, allowing the phone to recharge wirelessly while not in use. This feature could, in principle, allow people living in locations without ready access to a conventional power outlet to harvest energy from a nearby cell phone tower instead.

“Our work demonstrates a simple and inexpensive approach to electromagnetic power harvesting,” said lead investigator Steven Cummer.  “The beauty of the design is that the basic building blocks are self-contained and additive. One can simply assemble more blocks to increase the scavenged power.”

The Duke study appears in the journal Applied Physics Letters in December 2013.

You May Like

UN Fears Rights Violations in China-backed Projects

UNHCHR investigates link between financing development and ignoring safeguards for human rights More

Boko Haram Violence Tests Nigerians’ Faith in Buhari

New president has promised to stem insurgency; he’s scheduled to meet with President Obama at White House July 20 More

Social Media Network Wants Privacy in User’s Hands

Encryption's popularity in messaging is exploding; now it's the foundation of a new social network More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Making Music, Fleeing Bombs: New Film on Sudan’s Internal Refugeesi
X
Carolyn Weaver
July 06, 2015 6:47 PM
In 2012, Sudanese filmmaker Hajooj Kuka went to make a documentary among civil war refugees in Sudan’s Blue Nile and Nuba Mountains region. What he found surprised him: music was helping to save people from bombing raids by their own government. VOA’s Carolyn Weaver has more.
Video

Video Making Music, Fleeing Bombs: New Film on Sudan’s Internal Refugees

In 2012, Sudanese filmmaker Hajooj Kuka went to make a documentary among civil war refugees in Sudan’s Blue Nile and Nuba Mountains region. What he found surprised him: music was helping to save people from bombing raids by their own government. VOA’s Carolyn Weaver has more.
Video

Video Rice Farmers Frustrated As Drought Grips Thailand

A severe drought in Thailand is limiting the growing season of the country’s important rice crop. Farmers are blaming the government for not doing more to protect a key export. Steve Sandford reports from Chiang Mai, Thailand.
Video

Video 'From This Day Forward' Reveals Difficult Journey of Transgender Parent

In her documentary, "From This Day Forward", filmmaker Sharon Shattuck reveals the personal journey of her transgender father, as he told his family that he always felt he was a woman inside and decided to live as one. VOA’s Penelope Poulou has more.
Video

Video Floodwaters Threaten Iconic American Home

The Farnsworth House in the Midwest State of Illinois is one of the most iconic homes in America. Thousands of tourists visit the site every year. Its location near a river inspired the design of the house, but, as VOA’s Kane Farabaugh reports, that very location is now threatening the existence of this National Historic Landmark.
Video

Video Olympics Construction Scars Sacred Korean Mountain

Environmentalists in South Korea are protesting a Winter Olympics construction project to build a ski slope through a 500-year-old protected forest. Brian Padden reports that although there is strong national support for hosting the 2018 Pyeongchang Winter Olympics, there are growing public concerns over the costs and possible ecological damage at the revered mountain.
Video

Video Xenophobia Victims in South Africa Flee Violence, Then Return

Many Malawians fled South Africa early this year after xenophobic attacks on African immigrants. But many quickly found life was no better at home and have returned to South Africa – often illegally and without jobs, and facing the tough task of having to start over. Lameck Masina and Anita Powell file from Johannesburg.
Video

Video Family of American Marine Calls for Release From Iranian Prison

As the crowd of journalists covering the Iran talks swells, so too do the opportunities for media coverage.  Hoping to catch the attention of high-level diplomats, the family of American-Iranian marine Amir Hekmati is in Vienna, pleading for his release from an Iranian prison after nearly 4 years.  VOA’s Heather Murdock reports from Vienna.
Video

Video UK Holds Terror Drill as MPs Mull Tunisia Response

After pledging a tough response to last Friday’s terror attack in Tunisia, which came just days before the 10th anniversary of the bomb attacks on London’s transport network, British security services are shifting their focus to overseas counter-terror operations. VOA's Henry Ridgwell has more.
Video

Video Obama on Cuba: This is What Change Looks Like

President Barack Obama says the United States will soon reopen its embassy in Cuba for the first time since 1961, ending a half-century of isolation. VOA White House correspondent Luis Ramirez reports.
Video

Video Hate Groups Spread Influence Via Internet

Hate groups of various kinds are using the Internet for propaganda and recruitment, and a Jewish human rights organization that monitors these groups, the Simon Wiesenthal Center, says their influence is growing. The messages are different, but the calls to hatred or violence are similar. VOA's Mike O’Sullivan reports.
Video

Video Blind Somali Journalist Defies Odds in Mogadishu

Despite improving security in the last few years, Somalia remains one of the most dangerous countries to be a journalist – even more so for someone who cannot see. Abdulaziz Billow has the story of journalist Abdifatah Hassan Kalgacal, who has been reporting from the Somali capital for the last decade despite being blind.
Video

Video Rabbi Hits Road to Heal Jewish-Muslim Relations in France

France is on high alert after last week's terrorist attack near the city Lyon, just six months after deadly Paris shootings. The attack have added new tensions to relations between French Jews and Muslims. France’s Jewish and Muslim communities also share a common heritage, though, and as far as one French rabbi is concerned, they are destined to be friends. From the Paris suburb of La Courneuve, Lisa Bryant reports about Rabbi Michel Serfaty and his friendship bus.

VOA Blogs