Carbonyl iron and barium ferrite powder (BaZn1.5Co0.5Fe16O27) were prepared in this work. The complex permittivity and
permeability spectra for rubber radar absorbing materials employing carbonyl iron and barium ferrite powders were measured.
A database describing the frequency dependence of the permittivities and permeabilities of the carbonyl iron and barium ferrite
microwave absorbers with various powder percentage compositions in 2–18GHz was created. Based on the database, the single-layer and
double-layer absorbers were designed and prepared, and their microwave absorption properties were investigated. The results indicate
that the carbonyl iron powder prepared via thermal decomposition of iron pentacarbonyl is single cubic iron and of spherical shape. The
barium ferrite powder is single W-type ferrite and a hexagonal flake. The absorption band of the double-layer microwave absorber is
obviously more than that of the single-layer absorber. The double-layer microwave absorbers with reflection loss o13 dB over the
range of 6–18GHz and reflection loss o8 dB over the range of 2–18GHz were prepared. The thicknesses of the absorbers are only 3.6
and 3.7 mm, respectively.