A simple method of approximating frequency characteristics of composites in a form convenient for time-domain numerical modeling is proposed. The frequency characteristics can be obtained from experiment or calculations based on the Maxwell Garnett mixing formalism. The resultant frequency characteristic might be of a complex shape corresponding to a combination of a number of absorption peaks. The approximation is made by a series of Debye-like terms using a genetic algorithm (GA). This leads to the necessity of taking a number of terms in the approximating series. Every term corresponds to its pole, i.e., the frequency where the maximum loss occurs. Some numerical examples are represented.

Meeting Name

IEEE International Symposium on Electromagnetic Compatibility (2004: Aug. 9-13, Santa Clara, CA)


Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory

Keywords and Phrases

Debye-Like Terms; FDTD Modeling; Maxwell Garnett Mixing Formalism; Absorption Peaks; Approximating Series; Approximation Theory; Composites; Finite Difference Time-Domain Analysis; Frequency Characteristics; Genetic Algorithm; Genetic Algorithms; Inhomogeneous Media; Multiphase Dielectric Mixtures; Permittivity; Permittivity Representation; Pole; Poles and Zeros; Time-Domain Numerical Modeling; Dielectric Mixtures; Computational Complexity; Electric Network Analysis; Electromagnetic Waves; Finite Difference Method; Mathematical Models; Microscopic Examination; Natural Frequencies; Numerical Methods; Parameter Estimation; Time Domain Analysis; Transmission Electron Microscopy; Dielectric Materials

International Standard Book Number (ISBN)


International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version

Final Version

File Type





© 2004 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.