Electromagnetic waves, including light, X-rays, microwaves and radio waves, are present in many aspects ofour daily lives and are employed in numerous applications, thanks to their flexibility and power: from the transmission of information and energy, to radar, to the diagnostic and therapeutic medicine. However, electromagnetic waves lose their effectiveness inside certain materials known as dissipative, which hinder their propagation and cause them to be transformed into other forms of energy.

A research group at Sapienza University of Rome, coordinated by the Department of Information Engineering, Electronics and Telecommunications (DIET), in collaboration with other Italian universities, has verified, for the first time, the physical phenomenon of deep penetration of electromagnetic fields into dissipative materials, using devices that allow the waves to "travel" through, for example, soil or biological tissues.

The research, published in the journal Scientific Reports, confirms in practice what was only demonstrated at a theoretical level in a previous study, back in 2018.

The result was achieved through a microwave antenna (called a leaky-wave antenna), which emits waves that exhibit field amplification in some areas of space or, in a completely innovative approach, through a particular prism that can also operate at optical frequencies.

Applications of these devices could include not only the detection of buried or submerged objects and deep interaction with biological tissues but also the transmission of information in dissipative materials, material analysis and microscopy.

"This work," says Fabrizio Frezza of Sapienza University, study coordinator, "opens the way to promising applications in imaging and spectroscopy, as well as in radar systems and medical treatments."

Although the study verifies the effect of deep penetration for a specific value of frequency and conductivity (the structures involved being typically narrow-band), it makes an important contribution to the technological development of numerous applications even in fields where, until now, only acoustic waves could be used, such as ultrasound and sonar.

References:

Verification of the electromagnetic deep‑penetration effect in the real world - Paolo Baccarelli, Alessandro Calcaterra, Fabrizio Frezza, Fabio Mangini, Nicholas Ricciardella, Patrizio Simeoni & Nicola Tedeschi - Scientific Reports 2021. DOI: 10.1038/s41598-021-95080-w

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