Microwave absorbing properties and structural design of microwave absorbers based on polyaniline and polyaniline/magnetite nanocomposite

Double-layer absorbers with enhanced microwave absorbing properties were designed based on polyaniline and polyaniline/magnetite composite with a total thickness of 1 mm. The double-layer microwave absorbers have better microwave absorbing properties than those of single-layer microwave absorbers, and the microwave absorbing properties of the double-layer structure are influenced by the coupling interactions between the absorbing layer and matching layer. When the absorbing layer is PANI with a thickness of 0.4 mm, and the matching layer is PANI/Fe3O4 composite with a thickness of 0.6 mm, the minimum reflection loss (RL) reaches −42 dB at 29.27 GHz and the absorption bandwidth with RL below −10 dB is about 11.8 GHz. While when PANI and PANI/Fe3O4 composite are acted as matching layer and absorbing layer, respectively, with the same thickness of 0.5 mm, a minimum RL value of −54 dB is observed at 33.72 GHz and the absorption bandwidth is about 11.28 GHz ranging from 27.24 to 38.52 GHz with the RL value below −10 dB.