密度对声子晶体带隙的影响

从弹性波动方程出发，利用平面波展开法计算二维（三维）声子晶体的带结构，研究散射体与基体的密度比对最低带隙的影响，得出了最低带隙宽度和带隙边界随密度比的变化规律.数值计算结果显示随着密度比的增加，带隙下边界的频率降低，而上边界的频率升高，从而增加带隙宽度，且带隙能级不变.

Influence of Density on Bandgap of Phononic Crystal

Starting from elastic wave equation,plane wave expansion method is used to calculate the band structure of two-dimensional(three-dimensional) phononic crystals.The dependence of the lowest bandgap on the density ratio of scatterer to host is discussed.The authors obtain the variation principle of the bandgap’s width and bandgap’s boundary with the variety of the density ratio.Numerical results show that the frequency of the bandgap’s lower boundary becomes small,while the upper boundary becomes big as the density ratio increases.So the width of the lowest bandgap increases，and energy level of the lowest bandgap is invariable.