在红外微纳结构吸收材料的研究中，对其等效光学常数的估计有助于理解材料的吸收、反射及辐射特性。常用的方法是依据等效介质理论将微纳结构等效为匀质材料，采用Smith于2002年提出的S参数法进行估计,而该方法没有直接反映微纳结构材料特性及几何结构与等效光学常数之间的关系。采用Drude-Lorentz模型描述红外微纳结构材料吸收性能的色散关系，根据有效电子数浓度理论和等效电路理论，以矩形结构吸收材料为代表，建立了红外微纳结构吸收材料的几何结构参数与Drude-Lorentz模型参数之间的函数关系。该模型建立了微纳材料的结构、材料参数与其光学常数之间的量化关系，为红外微纳结构吸收材料的设计提供了理论依据。

The estimation of equivalent optical parameters of the nanostructure absorber materials will help to understand its absorption, reflection and radiation characteristics. The effective optical parameters of the metamaterials are estimated by the S-parameters proposed by Smith in 2002, which assumes the nanostructure metamaterials to be homogeneous bulk material, without reflecting the relationship between the equivalent optical parament, the geometrical structure and material characteristics. Here an analytical theory in which the Drude-Lorentz model is adopted to describe the dispersion relations of metamaterials′ absorptive characteristics in infrared (IR) is presented. Based on the effective electron density and the equivalent circuit analysis, a functional description between the geometrical parameters and its Drude-Lorentz model parameters has been built. This analysis on periodic arrangements of rectangular structures array is performed. The model establishes the quantitative relationship between structure parameters, material parameters and its optical constants. It offers an accurate prediction for their dispersive behavior at near-IR wavelengths.