In the future, clean alternatives such as harvesting energy from electromagnetic waves may help ease the world’s energy shortage
For our modern, technologically-advanced society, in which technology has become the solution to a myriad of challenges, energy is critical not only for growth but also, more importantly, survival. The sun is an abundant and practically infinite source of energy, so researchers around the world are racing to create novel approaches to "harvest" clean energy from the sun or transfer that energy to other sources.
This week in the journal Applied Physics Letters, from AIP Publishing, researchers from the University of Waterloo in Canada report a novel design for electromagnetic energy harvesting based on the "full absorption concept." This involves the use of metamaterials that can be tailored to produce media that neither reflects nor transmits any power—enabling full absorption of incident waves at a specific range of frequencies and polarizations.
"The growing demand for electrical energy around the globe is the main factor driving our research," said Thamer Almoneef, a Ph.D. student. "More than 80 percent of our energy today comes from burning fossil fuels, which is both harmful to our environment and unsustainable as well. In our group, we’re trying to help solve the energy crisis by improving the efficiency of electromagnetic energy-harvesting systems."
Since the inception of collecting and harvesting electromagnetic energy, classical dipole patch antennas have been used. "Now, our technology introduces ‘metasurfaces’ that are much better energy collectors than classical antennas," explained Omar M. Ramahi, professor of electrical and computer engineering.
Metasurfaces are formed by etching the surface of a material with an elegant pattern of periodic shapes. The particular dimensions of these patterns and their proximity to each other can be tuned to provide "near-unity" energy absorption. This energy is then channeled to a load through a conducting path that connects the metasurface to a ground plane.
The key significance of the researchers’ work is that it demonstrates for the first time that it’s possible to collect essentially all of the electromagnetic energy that falls onto a surface.
"Conventional antennas can channel electromagnetic energy to a load—but at much lower energy absorption efficiency levels," said Ramahi. "We can also channel the absorbed energy into a load, rather than having the energy dissipate in the material as was done in previous works."
As you can imagine, this work has a broad range of applications. Among the most important is space solar power, an emerging critical technology that can significantly help to address energy shortages. It converts solar rays into microwaves—using conventional photovoltaic solar panels—and then beams the microwave’s energy to microwave collector farms at designated locations on Earth. Japan is way out in front of rest of the world in this realm, with plans to begin harvesting solar power from space by 2030.
"Our research enables significantly higher energy absorption than classical antennas," Ramahi said. "This results in a significant reduction of the energy harvesting surface footprint. Real estate is a precious commodity for energy absorption—whether it’s wind, hydro, solar or electromagnetic energy."
Other key applications include "wireless power transfer—directly adaptable to power remote devices such as RFID devices and tags or even remote devices in general," Ramahi noted.
The technology can also be extended to the infrared and visible spectra. "We’ve already extended our work into the infrared frequency regime and we hope to report very soon about near-unity absorption in those higher-frequency regimes," added Ramahi.
The article, "Metamaterial electromagnetic energy harvester with near unity efficiency," is authored by Thamer S. Almoneef and Omar M. Ramahi. It will appear in the journal Applied Physics Letters on April 14, 2015 (DOI: 10.1063/1.4916232). After that date it can be accessed at: http://scitation.aip.org/content/aip/journal/apl/106/15/10.1063/1.4916232
The authors of this paper are affiliated with the University of Waterloo.
ABOUT THE JOURNAL
Applied Physics Letters features concise, rapid reports on significant new findings in applied physics. The journal covers new experimental and theoretical research on applications of physics phenomena related to all branches of science, engineering, and modern technology. See: http://apl.aip.org
Jason Socrates Bardi
Jason Socrates Bardi | newswise
Researchers take next step toward fusion energy
16.11.2017 | Texas A&M University
Desert solar to fuel centuries of air travel
16.11.2017 | SolarPACES
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
22.11.2017 | Business and Finance
22.11.2017 | Physics and Astronomy
22.11.2017 | Physics and Astronomy