This paper considers the case of a wide-band Lorentzian (WBL) algorithm in the finite-difference time-domain (FDTD) modeling of dispersive media. It is shown herein that the WBL model is a physically meaningful and practically useful case of the frequency behavior of materials along with the Debye and narrow-band Lorentzian (NBL). The recursive convolution algorithms for the finite-differencé time-domain technique for NBL and WBL models differ. The Debye model, which is suitable for comparatively low-frequency dispersive materials, may not have sufficient number of parameters for describing the wide-band material, especially if this material exhibits pronounced absorption at higher frequencies. It is shown that the Debye model can be used, if the Q-factor of the linear circuit analog corresponding to the Lorentzian model of the material is less than approximately 0.8. If the quality factor is in the limits of about 0.8 < Q < 1, then the WBL model is appropriate. For Q > 1, the NBL model must be applied. The NBL model is suitable for dielectrics exhibiting resonance effects in the microwave frequency range. The WBL model is typical for composites filled with conducting fibers.
M. Koledintseva et al., "Wide-Band Lorentzian Media in the FDTD Algorithm," IEEE Transactions Electromagnetic Compatability, Institute of Electrical and Electronics Engineers (IEEE), May 2005.
The definitive version is available at http://dx.doi.org/10.1109/TEMC.2005.847406
Electrical and Computer Engineering
Keywords and Phrases
Debye Model; Lorentzian Model; Dispersive Media; Finite-Difference Time-Domain (FDTD) Technique; Recursive Convolution
Article - Journal
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