The influence of addition of a low-loss linear dielectric material to a tunable ferroelectric material has been investigated in terms of the electrostatic consideration. The calculations of the dielectric loss and dielectric non-linearity of ferroelectric-dielectric composites have been performed by using three different models. On the basis of results obtained, the figure of merit of the composite material has been evaluated. No improvement of the figure of merit of composite material compared to the pure ferroelectric has been observed for the considered models. (C) 2003 Elsevier Ltd. All rights reserved.