(Fe, Ni)/C nanocapsules for electromagnetic-wave-absorber in the whole Ku-band

The natural resonance appears at 16 GHz for (Fe, Ni)/C nanocapsules with (Fe, Ni) alloys as cores and graphite as shells. Reflection loss (RL) exceeding −10 dB was obtained in the whole Ku-band (12.4–18 GHz) for an absorber thickness of 2.0 mm, while it exceeds −20 dB over the 13.6–16.6 GHz range. In addition, the bandwidth does not change dramatically for the thicknesses of 1.87–2.1 mm for the RL values exceeding −10 dB. The (Fe, Ni)/C nanocapsules with wide bandwidth absorption can be used as excellent electromagnetic-wave-absorption materials in the whole Ku-band.