The electromagnetic characteristics of the composites based on hexaferrites and MCNT at gigahertz and terahertz frequency bands

In this paper there are results of simulation, experimental investigation of electromagnetic characteristics and structure parameters of composite based on nanosized powder of hexaferrite Sr
_0.5
Ba
_0.5
CoZnFe
₁₆
O
₂₇
and MCNT. MCNT were prepared by ccatalytic chemical vapor deposition (CVD) method. Parameters of MCNT are: average diameter 18.6 nm; walls thickness 12-14 layers. Nanosized powders of hexaferrite were obtained by self-propagating high-temperature synthesis with master phase more than 85% in volume. Synthesized material has the range of signal attenuation is from 5 to 11.5 GHz (RL <; -10 dB) when thickness is 2 mm. Same results were obtained for pure hexaferrite with thickness 3.7 mm. Investigation in terahertz frequency band showed that absorption coefficient for synthesized material was over than 60% and absorption coefficient determines by permittivity of MCNT. Thus, synthesized material based on mixture of hexaferrite and MCNT has comparable reflection coefficient at -10 dB with considerable less thickness. Synthesized material can be used to decrease the intensity of reflection of electromagnetic waves. This material has high absorption coefficients and relatively low transmission and reflection coefficients.