基于电磁超材料的两种等效参数提取算法的比较分析

基于传统反演算法和Kramers-Kronig关系改进算法, 分别提取弱耦合和强耦合超材料渔网结构模型的等效参数, 并对两种算法的有效性及普适性进行了探讨.理论分析及计算结果表明, 传统的反演算法可以准确地反演弱、强耦合情形下电磁超材料结构的等效参数, 但计算复杂度较高;而基于Kramers-Kronig关系的改进算法巧妙地降低了计算的复杂度, 能简单准确地提取弱耦合情形下电磁超材料结构的等效参数, 但对于强耦合情形则不适用, 原因在于强耦合情形破坏了Kramers-Kronig关系的解析且连续性要求. 研究结果拓展了等效媒质理论并可为新的电磁超材料的设计提供理论参考.关键词：超材料反演算法Kramers-Kronig关系等效参数

The comparisons between two retrieve algorithms for metamaterials

Extracting the equivalent parameters of the weak-coupling and strong-coupling fishnet structure metamaterial based on the traditional retrieval algorithm and the improved algorithm of Kramers-Kronig relations are proposed, respectively. A comparative analysis of the effectiveness and applicability of the two algorithms are also included. The theoretical analysis and numerical results show that the traditional retrieval algorithm can retrieve the equivalent parameters of the weak-coupling and strong-coupling cases of electromagnetic metamaterials accurately, but with high computational complexity. While the improved algorithm based on the Kramers-Kronig relations can reduce the computational complexity and extract the equivalent parameters only for the weak-coupling case of electromagnetic metamaterials. However, it is not suitable for the strong-coupling case which may disobey the continuity requirement of the Kramers-Kronig relations. The presented results may extend the equivalent medium theory and provide a theoretical reference for the design of new metamaterials.