Numerical examination on effective permittivity of periodic structure by the FDTD method

摘要

The effective permittivity of the one-dimensional periodic structure is examined using the reflectance and transmissivity obtained by the FDTD method. By using the reflectance and transmissivity by the FDTD method, the effective permittivity of the dielectric slab, which has the same reflectance and transmissivity with that of periodic structure, is obtained by using the transcendental equation. Also, the effective permittivity is calculated by Rytov approximation, and the range of application and the validity of the effective permittivity are shown by comparing the Rytov approximation with the approximation obtained by the FDTD method.