Effect of structure parameters on the bandgap of two dimensional Archimedes A7 photonic crystals
结构参数对二维Archimedes A7晶格光子晶体禁带的影响

Plane wave expansion method is introduced to simulate the band structures of two-dimensional photonic crystals made of Archimedes A7 lattice of circular and square dielectric rod in air. The bandgaps of Archimedes A7 lattice with dielectric rods is also discussed as the refractive index, filling fraction and rotation angle change. The results show that the complete bandgap can be obtained when the refractive index is greater than 2.40, the width of complete bandgap reaches the maximum when the dielectric refractive index of the circular rod is equal to 2.60. For the Archimedes A7 lattice of square dielectric rod, the complete bandgap reaches the maximum when the dielectric refractive index equals 3.80, and the maximum complete bandgap changes in a narrow range as the refractive index increases. When the rotation angle of square dielectric rods changes, the maximum bandgaps can be attained steadily as the refractive index is a constant, the filling fraction scope where the complete bandgap appears significantly expanded.