应用平面波展开法研究了二维复合介质柱光子晶体中引入缺陷和改变其折射率对传输特性的影响，得到了不同尺寸和介电常数下的透射谱，并与无复合介质柱光子晶体的结果进行了比较。结果表明:复合柱越细，禁带越宽，中心频率越高，变化关系与无复合柱的结果相反；复合柱折射率越大，禁带越窄，中心频率越低，与无复合柱的结果相同。

For twodimensional photonic crystal(PC) with composite medium triangular rods, the effects of defects and refractive index on its transmission properties were investigated using the plane wave expansion（PWM）method. The transmission spectrum with different size and refractive index is obtained and is compared with the results of the PC without composite medium rods. It is shown that the thinner the composite medium rod is, the wider the band gaps is, and the higher the central frequency is, which is reversed to the results of PC without composite medium rods. The higher the composite refractive index is, the lower is the band gap and the central frequency, which is similar to the case without the composite medium rods.