Radar absorbing materials are used in the military sphere to make aeroplanes and other equipment "invisible" to radars. They are also used to paint the inside of special rooms, "anechoic chambers," designed for testing radio-emitting devices. These materials are also used in microwave technology.
The quality requirements for radar-absorbing coatings are constantly increasing. The electromagnetic absorption level depends on the electric permittivity. "Natural" materials don’t always have the necessary permittivity; therefore artificial composite materials are widely used, for example, pieces of iron or short pieces of thin wire mixed into hardened plastic.
"Together with Igor Lagunov, we have constructed the theory of artificial dielectric based on thin conductive squares distributed in a bonding medium. The calculation of the characteristics of such a composite has proved its applicability as an effective radio absorber," Vladimir Ponomarenko, professor of experimental physics at the CFU Institute of Physics and Technology, said.
According to Ponomarenko, the study was based on a new method for solving diffraction problems on periodic structures, using mathematical computational methods and computer modelling. Numerical calculations showed that, at the same thickness, a resistive square-based radar absorber has an almost twice lower reflection level in a wide frequency range compared to the known analogue.
Scientists say that the study results open up the possibility of creating new, more advanced radar-absorbing coatings with a low specific gravity for applications including military equipment and anechoic chambers. Ponomarenko said that due to the scaling of the dielectric structures, it is possible to change the range of its radio absorption.
The next stage will be the development of the manufacturing technique for radar absorbing materials and the creation of samples for special production enterprises.