Domain integral representation vs. homogenization methods for the analysisof photonic band gaps and absorbers

The reflectivity of two-dimensional pyramidal absorbers and the transmittan ce of photonic crystals made of dielectric fibers is analyzed by means of t wo approaches. In the first one an integral representation of the scattered field is used and the absorbers are modeled by a stack of gratings of infi nite extent. In the second approach, the absorbers and the crystal are repl aced by an equivalent multilayered medium obtained by means of two homogeni zation methods. We assess the efficiency of these methods with respect to p arameters such as the density of the gratings, their relative permittivity and the polarization of the incident wave.