Two-dimensional square lattice elliptical dielectric rods photonic crystal bandgap characteristics

The characteristics of complete bandgap in Two-dimensional square lattice elliptical column photonic crystal (PC) are investigated using a plane wave expansion method. In order to obtain the maximal bandgap width, one of the ellipse axes is fixed to 0.3a (a is the lattice constant), varying the other axis from 0.1a to 0.5a with a step length of 0.01a. For each geometric shape, the absolute complete bandgap as while as the relative complete bandgap are calculated. Then change the relative dielectric constant, a similar process is undergone. The data shown in this paper are good guide to the design of larger bandgap of PC structure.