Effective Constitutive Parameters Retrieval Method for Bianisotropic Metamaterials Using Waveguide Measurements

An effective method for extraction of electromagnetic properties of bianisotropic biaxial omega-type metamaterial (MM) slabs from waveguide measurements is presented. The method relies on measurements of S-parameters of two MM slab configurations (transverse and longitudinal) to extract electromagnetic properties endowed with strong bianisotropic coupling. An uncertainty analysis is performed for examining the effect of geometrical parameters of the longitudinal configuration on its resonance characteristic. For verification of the proposed method, constitutive parameters of a polyethylene sample are extracted at the X-band (8.2-12.4 GHz). Then, the method is applied for extraction of electromagnetic properties of an MM slab (square split-ring resonators over FR4 substrate) using simulated and measured S-parameters for the two configurations at the X-band. It is noted that extracted electromagnetic properties obtained from measured S-parameters are in good agreement with those obtained from simulated S-parameters except for a small frequency shift and magnitude change, which could arise from fabrication tolerances, air gaps present between MM cells, and local irregular surface of the longitudinal configuration. For completeness, it is analyzed whether extracted properties satisfy the locality conditions.