Multi-interface nanocomposite for band and thin microwave absorption application

• Multi-interface structure can enhance relaxation loss and form impedance matching. • Large attenuation and good loss capacity are realized through multi-interface. • Absorption ratio is 72.7% and effective absorbing bandwidth is 4.88 GHz at 1.7 mm. Synchronously enhancing relaxation loss and constructing impedance matching are challenges for microwave applications. For addressing this issue, multi-interface nanocomposites are prepared and their microstructure is that carbon nanorod with tiny Fe 2 O 3 nanoparticles are covered by Al 2 O 3 layer, in which FeNi nanoparticles encapsulated by Al 2 O 3 layer locates on carbon nanorod. Multi-interfaces of Al 2 O 3 -carbon, Fe 2 O 3 -carbon, FeNi-carbon, FeNi-Al 2 O 3 are constructed. Proper impedance matching, large attenuation constant and good dielectric loss capacity are realized through multi-interface structure. These merits ensure that composites possess absorption ratio of 72.7%, reflection loss of −14.18 GHz at 1.5 mm, effective absorbing bandwidth of 4.88 GHz at 1.7 mm.