Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fractals help UCLA researchers design antennas for new wireless devices

22.10.2002


Antennas for the next generation of cellphones and other wireless communications devices may bear a striking resemblance to the Santa Monica Mountains or possibly the California coastline.



That is because UCLA researchers are using fractals -- mathematical models of mountains, trees and coastlines -- to develop antennas that meet the challenging requirements presented by the more sophisticated technology in new cellphones, automobiles and mobile communications devices. These antennas must be miniature and they must be able to operate at different frequencies, simultaneously.

"Manufacturers of wireless equipment, and particularly those in the automotive industry, are interested in developing a single, compact antenna that can perform all the functions necessary to operate AM and FM radios, cellular communications and navigation systems," said Yahya Rahmat-Samii.


Rahmat-Samii, who chairs the electrical engineering department at UCLA’s Henry Samueli School of Engineering and Applied Science, leads the research in this area. His findings were reported in a recent issue of the Institute of Electrical and Electronics Engineers’ Antennas and Propagation Magazine.

Fractals, short for "fractional dimension," are mathematical models originally used to measure jagged contours such as coastlines. Like a mountain range whose profile appears equally craggy when observed from both far and near, fractals are used to define curves and surfaces, independent of their scale. Any portion of the curve, when enlarged, appears identical to the whole curve -- a property known as "self-symmetry."

Rahmat-Samii found the mathematical principles behind the repetition of these geometrical structures with similar shapes could be applied to a methodology for developing antenna designs.

Using this method, he has developed antennas that meet two important challenges presented by the new generation of wireless devices. They conserve space and can operate simultaneously at several different frequencies.

His fractal methodology allows Rahmat-Samii to pack more electrical length into smaller spaces, he said. Increased electrical length means the antennas can resonate at lower frequencies.

Because fractal designs are self-symmetrical (repeat themselves), they are effective in developing antennas that operate at several different frequencies. "One portion of the antenna can resonate at one frequency while another portion resonates at another frequency," Rahmat-Samii said.

UCLA, where much of the early research on internal antennas was conducted in the mid 1990s, is today "one of the leading research institutions exploring the use of fractals in developing antenna design," Rahmat-Samii said.

The subject of fractals came into vogue during the last decade as new-age gurus claimed fractals were capable of all manner of feats. Serious use in engineering, however, has developed over the last five years, Rahmat-Samii said.

This is not the first time Rahmat-Samii has borrowed from other disciplines. He has experimented with using "genetic algorithms" -- the Darwinian notion of natural selection and evolution -- as a means of developing alternative antenna designs. In keeping with the evolutionary model, a computer program "mates" various antenna components to produce new designs. Just as nature does, the algorithm selects the "fittest" design. The process is complete when it has produced a design that meets the experimenter’s objectives.

Although the method produces unanticipated results, it also provides few clues about the next iteration of the design, Rahmat-Samii said. Using fractals, however, makes the process more predictable, giving researchers more control over the results.

David Brown | EurekAlert!

More articles from Process Engineering:

nachricht Quick, Precise, but not Cold
17.05.2017 | Fraunhofer-Institut für Lasertechnik ILT

nachricht A laser for divers
03.05.2017 | Laser Zentrum Hannover e.V.

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>