Calculation of dielectric constant and loss of two-phase composites

The field distribution, dielectric constant, and loss in a two-phase composite, in which phase A is distributed inside a square matrix of phase B, have been calculated using the finite-element method (FEM). The calculation was carried out by taking into account different shapes for phase A, such as circles, triangles, and rings with different sizes. The modeling by FEM in the dielectric composite indicates that the shape for phase A has an influence on the electric-field distribution. In the case of the triangular shape of phase A, the electric flux condensed on the sharp angles of phase A. In a particular case of a ring for phase A, the electric-field distribution in the composite was quite different from that of circles/triangles due to the shielding effect of flux, and hence the dielectric constant and loss are greatly changed. The calculated values are analyzed and compared with that from the empirical Licktenecher relation. The results indicate that the FEM method can reflect the change in the shape and size of the particles of a composite and provide more reasonable results than that from the empirical Licktenecher relation. (C) 2003 American Institute of Physics.