一种提取介质结构等效电磁参量的改进方法

An Improved Effective Electromagnetic Parameters Retrieval Method

基于对提取人工电磁材料等效结构电磁参量的传统S参数提取法的研究,提出一种新的既适用于异向介质也适用于传统介质简单明确的改进方法。改进方法具有3个优势:1)采用反正弦函数提取等效折射率n,无需使用附加限制条件n′′≥0和z′≥0便可直接得出n的正负属性,避免了传统S参数提取法应用上述限制条件可能引起的误差;2)明确给出一种多值反正弦函数的取值方案,解决了传统S参数提取法中多值反三角函数的取值困扰问题;3)改进方法对厚度较小或厚度较大的介质结构都能适用,克服了传统S参数提取法仅适用于介质厚度足够小的限制。通过对均匀异向介质板、均匀传统介质板以及典型的SRR-Rods异向介质结构等效特性参量的提取,证实了此方法的正确性、有效性和优越性。

This paper presents a novel improved method to retrieve the effective constitutive electromagnetic parameters of metamaterials based on the investigation of traditional S-parameter retrieval method.This method can be applied to both left-handed metamaterials（LHM） and traditional right-handed metamaterials.The improved method possesses three advantages.1） The improved method employs inverse sine function to retrieve effective refractive index n.It can obtain the correct sign of n naturally without the additional constraint conditions n′′≥ 0and z′≥ 0.It can avoid the potential errors of judgment induced by using the above two conditions.2） It gives a very clear and definite solution to select the correct branches of the multi-value inverse sine function,which solves the well-known ＂branch＂ problem of traditional S-parameter retrieval.3） The proposed method can be used to both thin and thick metamaterials.It overcomes the limit that the traditional S-parameter retrieval works well only for thin slabs.The proposed method is applied to homogeneous double-negative and double-positive slabs,as well as the typical SRR-rods LHM.The successful retrieval results prove the correctness and effectiveness of the proposed method.