本篇論文採用平面波展開法 ( plane wave expansion ) 計算外加磁場後,電磁波在色散性介質光子晶體的能帶結構 ( band structure )。對於未加磁場的介電質,我們使用Drude modol 形式的色散型介電係數 ( permittivity )。本論文主要探討外加磁場對於色散性光子晶體能帶結構圖的影響,並討論利用能帶結構改變後所出現的光子能隙 ( photonic band gap ) 來控制電磁波在色散性光子晶體內部傳播狀態的可能性,以設計可操控光傳播的可調式光子晶體元件。;In this thesis, we use plane wave expansion (PWE) method to calculate the band structures of two-dimentional dispersive and magnetized dielectric photonic crystals consisting of periodically arranged cylinders whose permittivity has the Drude model type dispersion before applying the magnetic field. My research is mainly about the effects on the band structure when the external magnetic field is applied to the dispersive photonic crystals. Based on the band structure characteristics we also discuss the possibility of designing tunable photonic component to control the propagation of light by tuning the photonic band gap via changing the intensity of the applied external magnetic field.