title: Microwave axial dielectric properties of carbon fiber.
abstract: Randomly distributed carbon fibers (CFs) reinforced epoxy resin composites are prepared by the pouring method, the dielectric properties of CF composites with different fiber content and length have been performed in the frequency range from 8.2 to 12.4 GHz. The complex permittivity of the composite increases with the fiber length, which is attributed to the decrease of depolarization field, and increases with the volume fraction, which is attributed to the increase of polarization. A formula, based on the theory of Reynolds-Hugh, is proposed to calculate the effective permittivity of CF composites, and validated by the experiments. The proposed formula is further applied to derive the axial permittivity of CF and analyze the effect of fiber length on the axial permittivity.
authors.affiliation: State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Hong
authors.affiliation: State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China.
authors.forename: Heng
authors.initials: H
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China.
authors.forename: Zhuan
authors.initials: Z
authors.lastname: Li