MATERIAL ABSORBING ELECTROMAGNETIC WAVES Russian patent published in 2015 - IPC H01Q17/00 H01F1/00 

FIELD: physics.

SUBSTANCE: present invention relates to a material which absorbs electromagnetic waves in a wide wavelength range, up to the infrared band, which can be used to prevent the undesirable effect of high-frequency radiation on microelectronic hardware components and humans, and to prevent unauthorised detection of surface and aerial objects. The disclosed composite material of a given composition, which provides minimum input wave impedance for an incident electromagnetic wave and absence of a reflected wave, characterised by local Bs values variable in the range of 0.7 T to 10 T, provides a method of absorbing and scattering electromagnetic waves on ferrimagnetic particles located in a corresponding medium in ferrimagnetic resonance conditions, in the presence of internal local fields Hintr, variable in the range of 560 kA/m to 8000 kA/m. The invention employs as an absorbent coating a material medium having low wave impedance, a composition of a polymer material and iron powder with particles having an average size of about 100 nm, having uniformly distributed fine monocrystalline monodomain and non-monodomain particles of hexaferrites, garnet ferrites and ferrospinels (hexaferrites have a special place in this series since they have a high value of the H_a field of internal magnetocrystalline anisotropy and a high value of 4pM_s) and fine particles of powdered Nd-Fe-B, used in production of elastic magnets with B_s≥0.7 T and H_c≈240-560 kA/m.

EFFECT: high level of absorption and low reflection coefficient of electromagnetic waves.