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With the radar even in the sea-bottom?
It has been shown that electromagnetic waves can propagate even in dissipative
materials.
The research coordinated for Sapienza by Fabrizio Frezza, is published in the journals
Optics Letters and Physical Review
The search for the wreck of a plane or a ship in the sea-bottom is nowadays mainly entrusted to devices
which exploit the underwater propagation of acoustic waves, as the sonar.
So far it has been impossible to employ more sophisticated techniques, as those based on electromagnetic
waves, due to the presence of phenomena which attenuate their propagation.
A Sapienza research group, of which are part Fabrizio Frezza and Nicola Tedeschi, from the Department of
Information Engineering, Electronis and Telecommunications, has proposed for the first time the use of a
particular antenna (called leaky-wave antenna) which allows electromagnetic waves to “travel” through
lossy materials, as for instance the sea depth.
Electromagnetic waves, as light, X rays, microwaves, radio waves, are much present in daily life and, due to
their flexibility and power, are suitable for a number of applications, from information transmission to
diagnostic techniques.
However, electromagnetic waves lose their effectiveness inside dissipative materials, which hinder their
propagation causing the transformation into other energy forms.
The antenna devised from the Sapienza researchers would allow electromagnetic waves to propagate inside
dissipative media without losing power or even growing.
“The antenna operates exploiting the characteristics of such peculiar waves which present, in certain regions
of space, an amplification of the radiated field – Fabrizio Frezza explains. The applications of such devices
could concern not only the detection of buried or immersed objects, but also the information transmission in
lossy media, material analysis and microscopy, the interaction with biological tissues.
The result, recently presented in Rome during the ASI (Italian Space Agency) Workshop “National
components for Space: state of the art, developments and perspectives” and in the framework of the
European Project COST Action TU1208, is based on theoretical studies published by the group in the
journals Optics Letters and Physical Review.
The study opens new roads to the technological development of a number of applications in scenarios where
so far only acoustic waves could be used.
Info:
Fabrizio Frezza - Department of Information Engineering, Electronis and Telecommunications, Sapienza
University of Rome
T (+39) 06 44 58 58 41
[email protected]