The bianisotropic medium model for left-handed metamaterials and numerical calculation of negative electromagnetic parameters

We introduce the bianisotropic medium model into left-handed metamaterials (LHMs). Based on the model, we propose a novel method, which differs from S-parameter retrieval method, to calculate the constitutive parameters of LHMs. Via the numerical calculation of permeability μ and permittivity ε{lunate}, the relation between resonance intensity and geometric parameters for arrays of hexagonal split-ring resonators (SRRs) is acquired. The dendritic structure allows for negative permeability μ in the frequency range of 7.6-9.4 GHz, which is in good agreement with experimental results. The permittivity spectra of arrays of continuous and cut wires reveal the plasmonic and ideal resonant responses, respectively. Moreover, the recovered permittivity ε{lunate} is free from antiresonance, which is consistent with physical laws.