Prediction of Effective Permittivity of Diphasic Dielectrics as a Function of Frequency

• Published in: IEEE transactions on dielectrics and electrical insulation Vol. 16; no. 3; pp. 793 - 808
• Main Authors: Koledintseva, M.Y., Patil, S.K., Schwartz, R.W., Huebner, W., Rozanov, K.N., Jianxiang Shen, Ji Chen
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.06.2009; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Analytical models; Capacitance; Capacitors; Circuits; Dielectric composites; Dielectric constant; Dielectrics; effective permittivity; Electric fields; Electric resistance; Electrical insulation; Equivalence; equivalent impedance; Frequency; Geometry; Impedance; Inclusions; Mathematical models; Permittivity
• ISSN: 1070-9878; 1558-4135
• DOI: 10.1109/TDEI.2009.5128520

An analytical model based on an equivalent impedance circuit for effective permittivity of a composite dielectric as a function of frequency with complex-shaped inclusions is presented. The geometry of the capacitor containing this composite dielectric is discretized into partial impedance elements, the total equivalent impedance is calculated, and the effective permittivity of the composite dielectric is obtained from this equivalent impedance. An example application using this method is given for an individual cell of a diphasic dielectric consisting of a high-permittivity spherical inclusion enclosed in a low-permittivity parallelepiped. The capacitance and resistance for individual discretized elements in the composite cell are modeled as a function of an inclusion radius. The proposed approach is then extended to a periodic three-dimensional structure comprised of multiple individual cells. The equivalent impedance model is valid for both static and alternating applied electric fields, over the entire range of volume fraction of inclusions. The equivalent impedance model has a few advantages over existing effective medium theories, including no limitations on the shape of inclusions or their separation distance.