Microwave-Absorption Properties of Three Kinds of Structured Cu/C Composites

The microwave-absorption properties of three kinds of (core-shell, uniform-mixing and double-layer structured) Cu/C composites are investigated in the 2-18 GHz frequency range. The results show that the Cu/C composites with core-shell structure are favorable to obtain higher relative permittivity and better microwave-absorption properties in comparison with other Cu/C composites. The reflection loss (RL) values exceeding -10 dB are obtained in 13.0-17.2 GHz at the absorber thickness of 1.6 mm for the core-shell structured Cu/C nanoparticles, which cover most of Ku-band (12-18 GHz). The excellent microwave-absorption properties may result from synergetic effects induced by the tightly-connected core-shell interfaces. The synergetic effects are explained by a simulated physical model, wherein both the interfacial polarizations and interfacial multiple reflections are responsible to the excellent microwave-absorption performances.