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 Dresdner scientists print tomorrow’s world
08.02.2017 | Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS

nachricht New technology for mass-production of complex molded composite components
23.01.2017 | Evonik Industries AG

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

From rocks in Colorado, evidence of a 'chaotic solar system'

23.02.2017 | Physics and Astronomy

'Quartz' crystals at the Earth's core power its magnetic field

23.02.2017 | Earth Sciences

Antimicrobial substances identified in Komodo dragon blood

23.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>