Parameter Retrieval of Chiral Metamaterials Based on the Causality Principle

摘要

The parameter retrieval method based on the causality principle and Kramers-Kronig relations, which has been proposed for extracting effective parameters of metamaterials (MTMs) is extended to extract effective parameters of chiral metamaterials (CMMs) as well. Using Kramers-Kroning relations, the branch selecting problem which is the challenge of effective media parameters retrieval methods could be simply removed. To demonstrate the validity of the method, first, the constitutive parameters of a homogeneous chiral media are retrieved in the excellent agreement with the supposed parameters. Second validation is achieved by extracting the effective parameters of two well-known CMM structures whose effective parameters have been reported in the literature. The results are in excellent agreement with the reports of the previous works. Finally, a new type of CMMs called windmill structure is suggested, and its effective parameters are then extracted using the proposed method.