  We have studied the effective response of composites of spherical particles
with a dielectric profile which varies along the radius of the particles. We
developed a differential effective dipole theory to compute the dipole moment
of individual spherical particle and hence the effective dielectric response of
a dilute suspension. The theory has been applied to two model dielectric
profiles. Moreover, we compare the approximate results with the exact results
of the power-law profile and the agreement is excellent.
