Group Theory Based Design of Isotropic Negative Refractive Index Metamaterials

Wongkasem, Nantakan; Akyurtlu, Alkim; Marx, and Kenneth

doi:10.2528/pier06062103

Cited by 34 publications

(20 citation statements)

References 24 publications

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“…The conductivity greatly influences the dielectric [3][4][5][6][7] and magnetic behavior of ferrites [8,9]. This created considerable interest in many research workers for the development and potential applications of ferrites in the electronic industry [10][11][12]. Now a days the study of ferrites has occupied an important place in the electronics technology [13].…”

Section: Introductionmentioning

confidence: 99%

INFLUENCE OF TIME AND TEMPERATURE ON RESISTIVITY AND MICROSTRUCTURE OF Cux Co1-x Fe2 O4 MIXED FERRITES

Bammannavar¹,

Naik²,

Pujar³

et al. 2008

PIER Letters

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Abstract-Copper-cobalt ferrites with general chemical formula Cu x Co 1−x Fe 2 O 4 (with x = 0.0, 0.4, 0.6 & 1.0) were prepared by ceramic method. The solid state reaction was confirmed by XRD patterns. DC conductivity was measured by two probe method. Electrical resistivity is found to increase on lowering of sintering temperature and time. At x = 1.0, the conduction is mainly due to hopping of electrons leading to n-type conductivity while at x = 0.0, conduction is due to holes leading to P-type conductivity. The lowest conduction at x = 0.4 is attributed to the electron hole compensation. SEM micrographs were obtained from JEOL scanning electron microscope. The micrographs reveal that an average grain size increases with sintering temperature and time as a result of decrease in porosity. This leads to the decrease in resistivity with sintering temperature and time. One of the factors for higher conductivity in ferrites is an increase in average grain size and decrease in pore concentration during the heat treatment.

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Section: Introductionmentioning

confidence: 99%

INFLUENCE OF TIME AND TEMPERATURE ON RESISTIVITY AND MICROSTRUCTURE OF Cux Co1-x Fe2 O4 MIXED FERRITES

Bammannavar¹,

Naik²,

Pujar³

et al. 2008

PIER Letters

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show abstract

“…In recent years, left-handed metamaterial (LHM), which possesses simultaneously negative permittivity and permeability, has attracted much attention because of its exotic electromagnetic properties and the potential applications [1][2][3][4][20][21][22][23][24][25][26][27][28][29][30]. In 2003, the behavior of wave propagation in media of which not all the principal elements of the permeability and permittivity tensors have the same sign is investigated [5].…”

Section: Introductionmentioning

confidence: 99%

Transition Behavior of K-Surface: From Hyperbola to Ellipse

Qiao¹,

Zheng²,

Zhang³

et al. 2008

PIER

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Abstract-The transition behavior of the k-surface of a lossy anisotropic indefinite slab is investigated. It is found that, if the material loss is taken into account, the k-surface does not show a sudden change from hyperbola to the ellipse when one principle element of the permittivity tensor changes from negative to positive. In fact, after introducing a small material loss, the shape of the k-surface can be a combination of a hyperbola and an ellipse, and a selective high directional transmission can be obtained in such a slab.

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“…In this section we make use of the homogenized form of the permeability and the permittivity dyads given by (20) and (21) and numerically evaluate the effective properties at the macro-scale level.…”

Section: Numerical Implementation Of the Homogenized Materials Modelmentioning

confidence: 99%

“…To a broader extent, the mostly intuitive or more recently simulation based design of materials with engineered permeability and permittivity, through carefully designed inclusions and the possible use of electronic components have been expanding through the decade [20][21][22][23][24]. Intuition of the expert designers at present is necessary for developing new devices as theory alone provides only basic designs.…”

Section: Introductionmentioning

confidence: 99%

Inverse Synthesis of Electromagnetic Materials Using Homogenization Based Topology Optimization

El-Kahlout¹,

Kızıltaş²

2011

PIER

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Abstract-Recent studies on artificial materials demonstrate that substantial improvements in electromagnetic response can be attained by combining different materials subject to desired metrics. However, the perfect material combination is unique and extremely difficult to determine without automated synthesis schemes. In this paper, we develop a versatile approach to design the microstructure of periodic materials with prescribed dielectric and magnetic material tensors. The proposed framework is based on a robust material model and generalized inverse synthesis tool relying on topology optimization. The former is derived using homogenization theory and asymptotic expansion applied to Maxwell equations and can characterize the effects of anisotropy and loss of materials with periodic unit cells of arbitrary geometries and multi-phases much smaller than the wavelength. Resulting Partial Differential Equation (PDE) is solved numerically using Finite Element Analysis (FEA) and is validated with results in literature. The material model proves to be fast and numerically stable even with complex inclusions. The topology optimization problem is applied for the first time towards designing the unit cell topology of periodic electromagnetic materials from scratch with desired dielectric and magnetic tensors using offthe-shelf materials, i.e., readily available constituents obtained from El-Kahlout and Kiziltas isotropic ceramic powders. The proposed framework's capability is demonstrated with five design examples. Design with anisotropic permittivity is also fabricated. Results show that the framework is capable of designing, in an automated fashion, non-intuitive material compositions from scratch with desired electromagnetic properties.

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Group Theory Based Design of Isotropic Negative Refractive Index Metamaterials

Cited by 34 publications

References 24 publications

INFLUENCE OF TIME AND TEMPERATURE ON RESISTIVITY AND MICROSTRUCTURE OF Cu<sub>x</sub> Co<sub>1-x</sub> Fe<sub>2</sub> O<sub>4</sub> MIXED FERRITES

INFLUENCE OF TIME AND TEMPERATURE ON RESISTIVITY AND MICROSTRUCTURE OF Cu<sub>x</sub> Co<sub>1-x</sub> Fe<sub>2</sub> O<sub>4</sub> MIXED FERRITES

Transition Behavior of K-Surface: From Hyperbola to Ellipse

Inverse Synthesis of Electromagnetic Materials Using Homogenization Based Topology Optimization

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