The effects on band gaps for the cross section’s Shape of the medium column in 2-D photonic crystals

Due to three types of conventional 2D photonic crystals with medium columnpsilas cross sectionspsila shapes of hexagon, rectangular and circular, the symmetry of the structures are decreased through changing the length proportion in X and Y directions of cross sections and central rotary angle in Cartesian coordinate system, with simulation using planar wave expansion method and comparisons, the conclusion is made that photonic crystal with this structure has the largest absolute PBG when the length proportion p in X and Y directions is about p=2, and the central rotary angle is about 60deg ~ 70deg or 110deg ~ 120deg for rectangle lattice structures and about 0deg or 180deg for triangle lattice structures.