Complex permittivity and microwave absorption properties of BaTiO 3–polyaniline composite

Abstract

BaTiO 3–polyaniline composites with different mixture ratios, 75/25, 50/50 and 25/75, have been prepared in polyurethane resin, keeping pigment to volume concentration (PVC) constant as ∼25 in all the samples. For this, BaTiO 3 powder by oxide route and polyaniline by chemical oxidation route have been synthesized. The complex permittivity ( ε ′ r − j ε ″ r ) and reflection loss (dB) of the composites have been measured at different microwave frequencies in X-band (8.2–12.4 GHz) employing vector network analyzer model PNA E8364B and software module 85071. Reflection loss (dB) has been calculated for different thicknesses of the composites using measured values of ε ′ r and ε ″ r . It is found that the absorption properties of the composite improve with increasing % of polyaniline. A maximum reflection loss of −15 dB (97% power absorption) at 10 GHz with a bandwidth of 3 GHz (full frequency width at half of the peak response) has been achieved. Materials can find applications in suppression of electromagnetic interference (EMI), and reduction of radar signature.