FDTD modeling of an artificially-synthesized absorbing medium

Special attention has been previously given to the study of periodic materials and wave propagation in periodic structures. Of particular interest is the possibility of using these periodic materials to achieve low reflection over a broad frequency band. We present a novel infinite periodic structure comprised of lossy dielectric and magnetic materials in a checkerboard-type configuration. The search for an artificial structure that exhibits a good match to free space was motivated by the fact that, to date, it has not been possible to find a real material which satisfies the criterion /spl epsiv/\´/sub r/=/spl mu/\´/sub r/ and /spl epsiv/"/sub r/=/spl mu/"/sub r/-or similar ones that present a perfect match to the free space-as does the well-known PML medium widely used for the finite difference time domain (FDTD) mesh truncation. The FDTD technique is applied in conjunction with a periodic boundary condition to calculate the scattered field from the periodic structure for normally-incident plane waves. Because the computation is carried out in the time domain, only one FDTD simulation is required to calculate the scattering parameters in the frequency range of interest.