Aplicação da técnica LOD em métodos no domínio do tempo e freqüência para modelagem de meios convencionais e metamateriais / Application of LOD technique in time and frequency domain methods for modelling conventional and metamaterial media

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

This work focuses on developing efficient numerical methods, both in time and frequency domains, for modeling wave propagation in structures that present conventional media and/or metamaterial media combinations, particularly the metamaterials where both permeability and permittivity are simultaneously negative. In some cases, the simulation of such structures represent a great challenge, due to the great computational requirements. An efficient way of solving this problem is the usage of operator splitting techniques, specifically the alternate direction implicit (ADI) technique, already explored both in time and frequency domains, and recently the locally one-dimensional (LOD) . This work dedicates special attention to the LOD technique, where, for the first time, this one was applied in a finite difference frequency domain wide-angle propagation method, which was denominated LOD FD-BPM. The next step was to extend its application to the time domain, the first approach was used in a finite difference time domain wave propagation method, denominated LOD TD-WPM. Next, the LOD technique was applied to the FDTD method, resulting in an implicit formalism, denominated LOD-FDTD, which presents a better computational efficiency than the traditional ADI-FDTD. These approaches present an excellent computational efficiency, due to the possibility of using greater time steps than those permitted by the Courant-Friedrich-Levy (CFL) stability condition, being unconditionally stable as a consequence of applying the Crank-Nicolson (CN) scheme as well. The LOD-FDTD method restriction, referring to its first order accuracy in time, was circumvented by using the operator division scheme known as Strang splitting (SS), resulting in a second order time method LOD-FDTD-SS. The FDTD, ADI-FDTD, LOD-FDTD and LOD-FDTD-SS methods were also implemented with a lossy Drude model, making, this way, possible an adequate metamaterial media modeling. Another important contribution of this work was the implementation of the split PML contour condition in the LOD-FDTD formalism for the simulation of open electromagnetic problems.

ASSUNTO(S)

lod fd-bpm lod fd-bpm lod-fdtd and metamarerial lod td-wpm lod-fdtd e metamarerial lod td-wpm

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