研究了具有相同磁导率，但由于石墨层厚度不同而导致不同介电常数的Ni/C纳米胶囊的电磁波吸收。最佳的工作频率可以出现在S波段和C波段，并实现很强的电磁波吸收。对于最佳性能的Ni/C纳米胶囊，在2.6-8.2 GHz频率实现超过-20 dB的反射损耗，在3GHz有极大值-40 dB。电磁波吸收性能的改进归因于最佳的电磁配匹和随壳层厚度增加而增强的偶极极化。

Frequency dependence of microwave reflection loss (RL). (a-c) RL of S1, S2 and S3 with different d values. (d) the dependence of the RL peak value and RL peak frequency on t_shell for d = 5.4 mm, 4.4 mm and 3.8 mm.

Enhancement of complex permittivity due to the thickening of the graphite shell. The inset shows an equivalency between core/shell structure (with complex permittivity ε₁ and ε₂) and uniform structure (with an equivalent complex permittivity γε₁). An agreement between experimental and theoretical ε_effeff(t_shell) is obtained.