Controlling the Permittivities and Permeabilities of Epoxy/Silver Nanocomposites

The electromagnetic properties of materials are generally frequency-dependent. Controlling the permittivities and the permeabilities of composites are commonly achieved in a narrow frequency range. This work characterizes the electromagnetic properties of the epoxy/silver nanocomposites using transmission/reflection method. The silver nanoparticles serving as electric dipoles enhance the permittivity as the volume fraction increases. On the other hand, the rapidly changing magnetic field induces current on the conducting silver particles resulting in a negative polarizability. The macroscopic magnetic susceptivities are negative under the long-wavelength limit. The electromagnetic properties are controllable and just slightly change over a very broad frequency range from 8 GHz to 110 GHz.