Maxwellian material based absorbing boundary conditions

Absorbing boundary conditions (ABCs) for the finite-difference time-domain (FDTD) method are introduced which arise from surrounding the simulation sp ace with lossy Maxwellian material layers. Generalizations of the standard Lorentz dispersion material model, the time-derivative and two-time-derivat ive Lorentz material models, are developed for this purpose. The advantages of this approach include the close connection of the ABCs with the actual absorber physics associated with Maxwell's equations, the avoidance of the field-equation splitting required by the Berenger PML layers, and reduced m emory and operation counts. Several multi-dimensional cases are presented t o quantify the efficacy of this Maxwellian material-based approach. (C) 199 9 Elsevier Science S.A. All rights reserved.