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An extraction technique is proposed for electromagnetic characterization of metal-backed multilayer metamaterial (MM) structures demonstrating reflection-asymmetric property. It uses recursive scattering parameters for direct and reversed configurations of a multilayer structure. The algorithm was validated by comparing the extracted electromagnetic properties of multilayer structures composed of different MM unit cells with those determined by one-layer-only S-parameter methods. Two-layer and three-layer multilayer structures composed of MM slabs with C-shaped and $\Omega $ -shaped rings and an FR4 material were fabricated and measured for experimental validation. A sensitivity analysis was also conducted to quantitatively evaluate the performance of our method against a small air gap between the multilayer structures and the short-circuit termination and between adjacent MM slabs within these structures. Strong agreement was observed between the resulted obtained using our method and measurements. [ABSTRACT FROM AUTHOR]

An attractive extraction method has been proposed to determine all constitutive parameters of diagonal permittivity and permeability tensors in addition to the coupling term (a total of seven quantities) of omega-type bianisotropic metamaterial (MM) slabs. Noniterative (no need to use any numerical method) and less-requirement (scattering parameters of two modes only) features put our method to the forefront over other similar methods in the literature. A bianisotropic MM slab synthesized by the Drude and Lorentz models and another bianisotropic MM slab constructed by split-ring resonators are considered to validate and examine the accuracy of our method. Finally, additional analyses are performed to test dependencies of our method on incidence angle and the number of cells and to investigate whether it retrieves a unique solution. [ABSTRACT FROM AUTHOR]

A method is proposed for unique and accurate permittivity ( \varepsilon r ) extraction of low-loss thin samples from reference-plane-invariant amplitude-only measurements without resorting to the information of explicit permittivity of a sample holder. Thanks to the amplitude-only measurements, it is possible to bypass the increased phase uncertainty of scattering parameters and retrieve unique \varepsilon r . An uncertainty analysis is followed to investigate improved accuracy attained by our method. Waveguide measurements at the $X$ -band are next conducted to measure \varepsilon r of polyethylene and polyvinyl chloride samples with different lengths (the sample holder is a soda-lime glass) for validation of the method and for comparison its accuracy with other methods. From the comparison, we note that reference-plane-dependent methods necessitate precise knowledge of sample location for accurate \varepsilon r retrieval. Besides, it is observed that while compared reference-plane-invariant techniques either require that the sample holder does not move while positioning the sample over it or produce more than one solution for \varepsilon r measurement of low-loss dielectric samples, our method removes these two problems. [ABSTRACT FROM PUBLISHER]

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. [ABSTRACT FROM AUTHOR]

We present an error correction algorithm for extraction of reflection and transmission scattering (S-) parameters of a two-port device without resorting to a complete two-port calibration. It is shown that S-parameters of thru and nonreflecting line connections in addition to S-parameters of an unknown device (and its reversed orientation) are needed for extracting full S-parameters of the device. For validation, we performed simulations for a chiral metamaterial (transmission asymmetric) and carried out measurements of S-parameters of an asymmetrically loaded waveguide section (reflection asymmetric). [ABSTRACT FROM PUBLISHER]