Pinpoint microwave resolution could lead to wireless power transfer

April 25, 2008
Pinpoint microwave resolution could lead to wireless power transfer

An experimental near-field plate is a patterned grating like surface that can focus electromagnetic waves to subwavelength resolutions. Photo by Cyan James

Researchers at the University of Michigan have focused microwaves to specks 20 times smaller than their wavelength and five times smaller than other devices have achieved.

This development could allow advances such as laptop computers that recharge without plugging in, higher-resolution microscopes for observing molecules, and CDs that can store vastly more data.

A paper on the research will be published in the April 25 edition of Science. Authors include Anthony Grbic, assistant professor of electrical engineering and computer science; Roberto Merlin, professor of physics as well as electrical engineering and computer science; and Lei Jiang, a graduate student in physics. The work is an experimental realization of a concept and device proposed earlier in two theoretical papers.

"This is the highest resolution to date achieved at microwave frequencies," Grbic said. "It opens up a whole range of applications, including wireless power transfer, microscopy and beam-shaping devices to focus the radiation. If we can push this to light frequencies, and there are no reasons why this couldn't be done, it will have applications in lithography and data storage."

Microwaves have a lower frequency and longer wavelength than visible light. Lithography is used in etching integrated circuits for computer processors and memory.

Focusing light waves and other electromagnetic radiation to points smaller than their wavelength was long thought to be impossible. But by manipulating these waves before they get too far away from their source, scientists and engineers in recent years have been able to break this so-called diffraction limit.

Grbic and his colleagues focused 30-cm microwaves at 1GHz frequency to points approximately 1.5 cm in size.

They achieved this by aiming the radiation through specially patterned, slotted panels placed within the source's electromagnetic near field. The electromagnetic near field is the region around an antenna or radiation source within one wavelength of the emitted radiation. In this case, the near field was within 30 cm of the source.

The slotted panels, called near-field plates, work as alternatives to lenses. Other methods of focusing beneath the diffraction limit use metamaterials, which are special man-made, three-dimensional lenses that are relatively expensive to produce.

The plates that Grbic, Merlin and Jiang produced are made by single-layer processing. They are easier to make and less expensive than metamaterials, they say.

"A big advantage of our approach is that the underlying focusing concept can be applied to a wide range of operating frequencies," Merlin said. "Much as the well-known Fresnel zone plates can be used for conventional (diffraction-limited) focusing of microwaves and X-rays, the near-field plates can do the same with super resolution."

Their study is called "Near-Field Plates: Subdiffraction Focusing with Patterned Surfaces."

Source: University of Michigan

4.6 /5 (59 votes)  

Filter


Move the slider to adjust rank threshold, so that you can hide some of the comments.


Display comments: newest first

earls
Apr 25, 2008

Rank: 3 / 5 (3)
Very light on the details and applications...

I'm assuming they mean "across the room" wireless power and not "sit the laptop on a mat" wireless power.
NeilFarbstein
Apr 25, 2008

Rank: 2 / 5 (4)
power mats are a really bad idea that should be outlawed. They are a danger to people. They will cause cataracts and cancer.
Glis
Apr 25, 2008

Rank: not rated yet
Wow, I hope they get this right for optical. SEM is a pain in the butt sometimes.
Rank 4.6 /5 (59 votes)
Tags

Relevant PhysicsForums posts
  • Books To Inspire a Beginnig Physics Student
    created1 hour ago
  • Pith balls problem
    created1 hour ago
  • Electrostatics
    created1 hour ago
  • what is phase constant
    created1 hour ago
  • Basics In electromagnetic wave
    created1 hour ago
  • How to calculate theoretical initial velocity?
    created2 hours ago
  • More from Physics Forums - General Physics

More news stories

Putting the squeeze on planets outside our solar system

(PhysOrg.com) -- Using high-powered lasers, scientists at Lawrence Livermore National Laboratory and collaborators discovered that molten magnesium silicate undergoes a phase change in the liquid state, abruptly ...

Physics / Condensed Matter

created 12 hours ago | popularity 4.3 / 5 (7) | comments 0 | with audio podcast

Hovering not hard if you're top-heavy, researchers find

Top-heavy structures are more likely to maintain their balance while hovering in the air than are those that bear a lower center of gravity, researchers at New York University's Courant Institute of Mathematical Sciences ...

Physics / General Physics

created 13 hours ago | popularity 5 / 5 (1) | comments 1 | with audio podcast

SLAC, Stanford team focuses on high-energy electrons to treat cancer

Accelerator physicists at SLAC and cancer specialists from Stanford are working on a new technology that could dramatically reduce the time needed for cancer radiation treatments. The team ran an initial experiment ...

Physics / General Physics

created 16 hours ago | popularity 5 / 5 (2) | comments 0

Measurements from high-energy collisions lead to better understanding of why meson particles disappear

For several years, physicists at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL), USA, have studied an unusual state of matter called the quark–gluon plasma, which they ...

Physics / General Physics

created 17 hours ago | popularity 4.5 / 5 (4) | comments 0

Explained: Sigma

It's a question that arises with virtually every major new finding in science or medicine: What makes a result reliable enough to be taken seriously? The answer has to do with statistical significance -- but ...

Physics / General Physics

created Feb 09, 2012 | popularity 5 / 5 (16) | comments 53


Anonymous knocks CIA website offline (Update)

The website of the Central Intelligence Agency was inaccessible on Friday after the hacker group Anonymous claimed to have knocked it offline.

Google users warned of threat to smartphone wallets

Users of Google smartphone wallets were being warned on Friday that there is a way to crack pass codes intended to thwart thieves from going on illicit shopping sprees.

New error-correcting codes guarantee the fastest possible rate of data transmission

Error-correcting codes are one of the triumphs of the digital age. They’re a way of encoding information so that it can be transmitted across a communication channel — such as an optical fiber o ...

Humans may have helped the decline of African rainforests 3000 years ago

(PhysOrg.com) -- Large areas of rainforests in Central Africa mysteriously disappeared over three thousand years ago, to be replaced by savannas. The prevailing theory has been that the cause was a change ...

New power source discovered

(PhysOrg.com) -- Researchers at the Massachusetts Institute of Technology (MIT) and RMIT University have made a breakthrough in energy storage and power generation.

Small modular reactor design could be a 'SUPERSTAR'

(PhysOrg.com) -- Though most of today's nuclear reactors are cooled by water, we've long known that there are alternatives; in fact, the world's first nuclear-powered electricity in 1951 came from a reactor ...