Retrieval and validation of the effective constitutive parameters of bianisotropic metamaterials

In this paper we present the exact bianisotropic parameter retrieval procedure for the case of transmission line metamaterials. The procedure assigns two different sets of effective parameters for two directions of propagation, which can be modelled by a bianisotropic medium. The procedure is applied to a microstrip line loaded with asymmetric edge-coupled split-ring resonators with gaps parallel and perpendicular to the line. The standard Nicolson-Ross-Weir procedure based on averaging of the S-parameters is not applicable to this case due to pronounced asymmetry. We also present the reverse procedure, which recovers the original S-parameters using the extracted effective permittivity and permeability, that fully validates the correctness of the proposed retrieval method. (paper)