An analytical model based on an equivalent capacitance circuit for expressing a static effective permittivity of a composite dielectric with complex-shaped inclusions is presented. The dielectric constant of 0-3 composites is investigated using this model. The geometry of the capacitor containing a composite dielectric is discretized into partial parallel-plate capacitor elements, and the effective permittivity of the composite is obtained from the equivalent capacitance of the structure. First, an individual cell diphasic dielectric (a high-permittivity spherical inclusion enclosed in a lower permittivity parallelepiped) is considered. The capacitance of this cell is modeled as a function of an inclusion radius/volume fraction. The proposed approach is extended over a periodic three-dimensional structure comprised of multiple individual cells. The results of modeling are compared with results obtained using different effective medium theories, including Maxwell Garnett, logarithmic, Bruggeman, series, and parallel mixing rules. It is found that the model predictions are in good agreement with the experimental data. The equivalent capacitance model may be applied to composites containing inclusions of any geometry and size. Although the method presented is at static electric field, it can be easily generalized for prediction of frequency-dependent effective permittivity.
S. K. Patil et al., "Prediction of Effective Permittivity of Diphasic Dielectrics Using an Equivalent Capacitance Model," Journal of Applied Physics, American Institute of Physics (AIP), Oct 2008.
The definitive version is available at http://dx.doi.org/10.1063/1.2976173
Electrical and Computer Engineering
Materials Science and Engineering
United States. Office of Naval Research
Keywords and Phrases
Cells (Electric); Permittivity; Capacitors; Composite materials
Article - Journal
© 2008 American Institute of Physics (AIP), All rights reserved.