Abstract: In this paper, the dispersion characteristics in 2-D dielectric PBG structure are analyzed by using FDTD method. The computed κ-ω curves show that under the same ratio of dielectric occupancy in the period cell and in the case of a single dielectric cylinder only, the dispersion curves are not sensitive to the geometry of this cylinder. However, in the case of multiple separat-ed cylinders, the central frequency of TM band-gap rises with the increased number of cylinders, and its relative bandwidth is almost constant.

Key words: dispersion characteristics, PBG structure, finite difference time-domain