Possibilities of using pigments with spinel structure as fillers and properties of composites containing them based on the styrene butadiene rubber

Flexible antennas are placed near or on the human body without having an adverse effect on it. Therefore, they must be comfortable, flexible and not contribute to discomfort. At the same time, they must have a small value of the tangent of the angle of dielectric loss (tan δ_ε), a minimum absorption of electromagnetic power, the ability to withstand mechanical loads and have a small change in the complex dielectric permittivity in a wide frequency range. The aim of the study is to verify the possibilities of using spinel pigments as fillers in styrene-butadiene rubber composites applicable as substrates and insulating layers in flexible portable antennas for wireless communications. It was found that the filler used has characteristics that ensure good performance of the antenna, combined with an aesthetic appearance. The optimal concentration of the spinel pigment, which determines the best operational characteristics of the antenna, has been established.