The Maxwell Garnett equation only describes the optical properties of a collection of perfectely spherical nanoparticles. However, the optical properties of nanocomposites are sensitive to the nanoparticles shape distribution. To overcome this limit, Y. Battie et al. have developed the shape distributed effective medium theory (SDEMT). This effective medium theory enables to calculate the effective dielectric function of a nanocomposite which consists in a collection of ellipsoïdal nanoparticles distributed in shape.
with 
The depolarization factors () only depend on the shape of nanoparticles.  is the distribution of depolarization factors.f is the volume fraction of the nanoparticles.
The SDEMT theory was used to extract the shape distribution of nanoparticles from absorption  or ellipsometric spectra.