Hasar, Ugur Cem; Buldu, Gul; Kaya, Yunus; Ozturk, Gokhan

A recursive algorithm is proposed to accurately extract the electromagnetic parameters of isotropic/bianisotropic metamaterial (MM) slabs of inhomogeneous structures. The algorithm is based on the recursive calculations of measured/ simulated forward and backward scattering (S-) parameters from previously extracted wave impedances and refractive indices of each homogeneous layer (except the analyzed intermediate layer) by a suitable retrieval method. There are two main advantages of our proposed method over existing extraction algorithms. First, it could retrieve the electromagnetic parameters of both isotropic and bianisotropic MM slabs. Second, it is applicable for electromagnetic parameter extraction of inhomogeneous structures. For validation of our method and assessing its accuracy over existing extraction methods, we used the simulation results of various inhomogeneous structures constructed by different isotropic/bianisotropic MM slabs (split-ring-resonator (SRR), SRR-wire, omega, and omega-wire). For completeness, the effects of noise present in S-parameters and iterative error (by increasing the value of iteration numbers) are examined to test the robustness of the proposed algorithm.

AtıfScopus43·WoS42·OpenAlex47

İncele

Hasar, Ugur C.; Buldu, Gul; Barroso, Joaquim J.

A retrieval method is proposed for electromagnetic parameter extraction of metamaterial (MM) slabs having electric coupling to magnetic resonance (weak coupling) from waveguide measurements. Underlying expressions of electromagnetic properties in the retrieval process are derived. The method is validated by the simulated and measured waveguide scattering parameters of an MM slab constructed by split-ring-resonators.

AtıfScopus13·WoS13·OpenAlex15

İncele

Hasar, U.C.; Buldu, G.; Bute, M.; Muratoglu, A.

A calibration-free method for extraction of electromagnetic properties of magnetically coupled anisotropic biaxial metamaterial (MM) slabs from waveguide measurements is proposed. It relies on three measurement steps (thru, empty line, and the same line arbitrarily loaded by the MM slab) to extract electromagnetic properties. It is evaluated against another calibration-dependent method for retrieval of electromagnetic properties of a MM slab constructed by C-shaped resonators. From evaluation analysis, we note that our method, as compared to the calibration-dependent method, not only accurately extracts electromagnetic properties without requiring the use of expensive calibration standards but also is reference-invariant.

AtıfScopus10·OpenAlex11

İncele

Hasar, Ugur Cem; Buldu, Gul; Barroso, Joaquim Jose

Metamaterials (MMs) are engineered material with electromagnetic properties not commonly seen by natural materials such as negative refraction and near-zero permittivity. These materials have interesting applications ranging from perfect lens and electromagnetic cloaks to leaky-wave antennas and shifters. For such applications, electromagnetic properties of MMs are needed to be known. In this study, we propose a waveguide method for accurate electromagnetic parameter retrieval of weakly-coupled MM slabs (the wavevector is normal to the plane of the metallic inclusions). To achieve our goal, new expressions for effective permittivity and permeability as well as the magnetoelectric coupling coefficient are derived. For validation of our waveguide method, we used the simulated scattering parameters of a MM slab composed of split-ring-resonator unit cells by using a commercial 3D electromagnetic simulation program.

AtıfScopus1·OpenAlex3

İncele

Hasar, U.C.; Buldu, G.

A microwave method has been proposed for accurate and unique extraction of relative complex permittivity (ϵr) of dielectric materials from 2π phase-ambiguity-free amplitude-only two-port and one-port scattering parameter measurements. Improved accuracy has been shown by the applied uncertainty analysis. For the validation of our method, ϵr of low-loss and lossy samples was extracted.

AtıfScopus2·WoS2·OpenAlex2

İncele