含椭球纳米颗粒复合介质的等效介电常数

利用S参数反演与MG(Maxwell-Garnett)有效介质理论计算了含椭球纳米颗粒复合介质的等效介电常数,考虑椭球体积分数和长宽比的影响,分析了两种等效模型的适用性。结果发现S参数反演对掺杂颗粒的形状和体积分数变化适应性较好,在所考虑的体积分数和长宽比下都能完美适用；而MG有效介质理论受体积分数和长宽比的影响较大,当椭球的长宽比为2、3或4时,其适用的最高体积分数分别为8%、4%或2%,因此随着椭球逐渐变扁,MG有效介质理论的适用范围会不断降低。 

Effective dielectric constant of composite medium containing ellipsoid nanoparticles

The S-parameter retrieval and MG (Maxwell-Garnett) effective medium theory were employed to calculate the effective dielectric constant of composite medium containing ellipsoid nanoparticles. Two influential factors, including volume fraction and aspect ratio of ellipsoid, were considered to analyze the applicability of the two effective models. Results showed that S-parameter retrieval had better adaptability to changes in shape and volume fraction of doped nanoparticles. In the considered volume fractions and aspect ratios, the S-parameter retrieval was well applicable. However, the MG effective medium theory was easily affected by the volume fraction and aspect ratio. When the aspect ratio of ellipsoid was 2, 3 or 4, the maximum volume fraction under applicable MG effective medium theory was 8%, 4% or 2%. Therefore, as the ellipsoid becomes flattened, the applicable range of MG effective medium theory will continue to decrease.