Numerical analysis, design and two port equivalent circuit models for split ring resonator arrays

Yaşar Örten, Pınar
Split ring resonator (SRR) is a metamaterial structure which displays negative permeability values over a relatively small bandwidth around its magnetic resonance frequency. Unit SRR cells and arrays have been used in various novel applications including the design of miniaturized microwave devices and antennas. When the SRR arrays are combined with the arrays of conducting wires, left handed materials can be constructed with the unusual property of having negative valued effective refractive indices. In this thesis, unit cells and arrays of single-ring multiple-split type SRR structures are numerically analyzed by using Ansoft’s HFSS software that is based on the finite elements method (FEM). Some of these structures are constructed over low-loss dielectric substrates and their complex scattering parameters are measured to verify the numerical simulation results. The major purpose of this study has been to establish equivalent circuit models to estimate the behavior of SRR structures in a simple and computationally efficient manner. For this purpose, individual single ring SRR cells with multiple splits are modeled by appropriate two-port RLC resonant circuits paying special attention to conductor and dielectric loss effects. Results obtained from these models are compared with the results of HFSS simulations which use either PEC/PMC (perfect electric conductor/perfect magnetic conductor) type or perfectly matched layer (PML) type boundary conditions. Interactions between the elements of SRR arrays such as the mutual inductance and capacitance effects as well as additional dielectric losses are also modeled by proper two-port equivalent circuits to describe the overall array behavior and to compute the associated transmission spectrum by simple MATLAB codes. Results of numerical HFSS simulations, equivalent circuit model computations and measurements are shown to be in good agreement.


Distinguishability for Magnetic Resonance-Electric Impedance Tomography (MR-EIT)
Altunel, H.; Eyüboğlu, Behçet Murat; KÖKSAL, ADNAN (2006-09-01)
In magnetic resonance-electrical impedance tomography, magnetic flux density due to current injection is the measured quantity. Different conductivity distributions create different magnetic flux density distributions. Distinguishability for MR-EIT is defined using this fact. The definition is general and valid for 2D as well as 3D structures of any shape. It is not always possible to find an analytic expression for distinguishability. However, when a 2D cylindrical body with concentric inhomogeneity is con...
Practical Realization of Magnetic Resonance Conductivity Tensor Imaging (MRCTI)
DEĞİRMENCİ, EVREN; Eyüboğlu, Behçet Murat (2013-03-01)
Magnetic resonance conductivity tensor imaging (MRCTI) is an emerging modality which reconstructs images of anisotropic conductivity distribution within a volume conductor. Images are reconstructed based on magnetic flux density distribution induced by an externally applied probing current, together with a resultant surface potential value. The induced magnetic flux density distribution is measured using magnetic resonance current density imaging techniques. In this study, MRCTI data acquisition is experime...
Circumferential Traveling Wave Slot Array on Cylindrical Substrate Integrated Waveguide (CSIW)
Bayraktar, Omer; Aydın Çivi, Hatice Özlem (Institute of Electrical and Electronics Engineers (IEEE), 2014-07-01)
Traveling wave slot array on cylindrical substrate integrated waveguide (CSIW) is designed, fabricated and measured at K-band. CSIW is formed by wrapping the substrate integrated waveguide (SIW) around the cylinder in the circumferential direction. 16 element longitudinal slot array on the broad wall of single CSIW is designed by the Elliot's design procedure. The spacings between the slot elements are determined to reduce the half power beam width (HPBW) and to obtain good matching at 25 GHz. A 4 x 16 slot...
Image Reconstruction in Magnetic Resonance Conductivity Tensor Imaging (MRCTI)
DEĞİRMENCİ, EVREN; Eyüboğlu, Behçet Murat (2012-03-01)
Almost all magnetic resonance electrical impedance tomography (MREIT) reconstruction algorithms proposed to date assume isotropic conductivity in order to simplify the image reconstruction. However, it is well known that most of biological tissues have anisotropic conductivity values. In this study, four novel anisotropic conductivity reconstruction algorithms are proposed to reconstruct high resolution conductivity tensor images. Performances of these four algorithms and a previously proposed algorithm are...
Simulations for a novel magnetic resonator with V-shaped structures
Ekmekci, Evren; Sayan, Gönül (2007-01-01)
It is demonstrated in this paper that a novel structure which consists of V-shaped conducting strips may exhibit magnetic resonance effect similar to the split ring resonator structures. The simulations have been done using Ansoft HFSS v9.2. By applying a time varying electric field to the V-shaped structure, the location of the resulting resonant frequency has been determined and furthermore, the dependency of resonance frequency on arm width, arm angle, and dielectric thickness have been investigated.
Citation Formats
P. Yaşar Örten, “Numerical analysis, design and two port equivalent circuit models for split ring resonator arrays,” M.S. - Master of Science, Middle East Technical University, 2010.