Effective dielectric response of a composite with aligned spheroidal inclusions

The effective dielectric response ${\mathrm{\epsilon }}_{\mathit{M}}$ of a composite with aligned spherodial inclusions is calculated. Using the dipolar and the mean-field approximation (MFA) an analytical expression for ${\mathrm{\epsilon }}_{\mathit{M}}$ as a functional of the two-particle distribution function ${\mathrm{\rho }}^{\mathrm{}\left(2\right)\mathrm{}}$ is obtained. It is shown that previous expressions reported in the literature correspond to different choices of ${\mathrm{\rho }}^{\mathrm{}\left(2\right)\mathrm{}}$, thus, clarifying the origin of their discrepancies. The theory is further extended beyond the MFA by including the dipolar fluctuations through a renormalization of the polarizability tensor of the inclusions. The absorption peaks are diminished and broadened by the spatial disorder, which also yields an easily identified coupling among electromagnetic modes with perpendicular polarizations.