Complex permittivity and microwave absorption properties of a composite dielectric absorber

Two types of composite samples were prepared using dielectric particulates such as BaTiO3, polyanitine and conducting carbon in polyurethane matrix. One of the composite samples contains synthesized BaTiO3 and polyaniline, while the other sample using, the commercial ingredients. Structural properties of both synthesized and commercial BaTiO3 and polyaniline have been investigated. Complex permittivity (epsilon(r)' - j epsilon(r)) and microwave absorption properties of the prepared composites were studied in X-band (8.2-13.5 GHz). An optimized composite sample with synthesized BaTiO3 and polyaniline has shown a maximum reflection loss of -25 dB (> 99% power absorption) at 11.2 GHz with a bandwidth (full frequency width at half of the maximum response) of 2.7 GHz in a sample thickness of 2.5 mm. The measured absorption values have been validated by theoretical calculations. Materials can find applications in suppression of electromagnetic interference (EMI) and reduction of radar signature. (c) 2005 Elsevier Ltd. All rights reserved.