The Finite Difference Time Domain Method for Sinusoidal Electromagnetic Fields

Md. Osman GONI  Masao KODAMA  

IEICE TRANSACTIONS on Electronics   Vol.E85-C   No.3   pp.823-830
Publication Date: 2002/03/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electromagnetic Theory
finite difference time domain (FDTD) method,  sinusoidal field,  surface impedance,  Q-factor of resonator,  

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The FDTD method needs Fourier analysis to obtain the fields of a single frequency. Furthermore, the frequency spectra of the fields used in the FDTD method ordinarily have wide bands, and all the fields in FDTD are treated as real numbers. Therefore, if the permittivity ε and the permeability µ of the medium depend on frequency, or if the surface impedance used for the surface impedance boundary condition (SIBC) depends on the frequency, the FDTD method becomes very complicated because of convolution integral. In the electromagnetic theory, we usually assume that the fields oscillate sinusoidally, and that the fields and ε and µ are complex numbers. The benefit of introduction of the complex numbers is very extensive. As we do in the usual electromagnetic theory, the authors assume that the fields in FDTD oscillate sinusoidally. In the proposed FDTD, the fields, ε, µ and the surface impedances for SIBC are all treated as the complex numbers. The proposed FDTD method can remove the above-mentioned weak points of the conventional FDTD method.