Calculation of Electromagnetic Constitutive Parameters of Insulating Magnetic Materials with Conducting Inclusions

1995 ◽  
Vol 408 ◽  
Author(s):  
Drs. Eric Kuster ◽  
Rick Moore ◽  
Lisa Lust ◽  
Paul Kemper
Keyword(s):  
Magnetic Properties ◽  
Correlation Length ◽  
Method Of Moments ◽  
Effective Permittivity ◽  
Frequency Dispersion ◽  
Effective Parameters ◽  
Electromagnetic Model ◽  
Permittivity And Permeability ◽  
The Matrix ◽  
Constitutive Parameters

AbstractA Method of Moments (MoM) electromagnetic model of percolating conducting films was applied to calculate the effective parameters of the composite formed by conducting inclusions placed within a dispersive magnetic but nondispersive dielectric matrix. The MoM calculations demonstrate a coupling between the magnetic properties of the matrix and the effective composite permittivity and frequency dispersion of the composite. The coupling of permittivity and permeability is observed near the percolation threshold of the composite and for high conductivity inclusions. The prediction agrees with physical expectations since near percolation the conduction correlation length dominates the effective permittivity of the composite and this correlation length is determined by both the permittivity and permeability of the composite.

scholarly journals Extension of the Multipole Approach to Random Metamaterials

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
A. Chipouline ◽  
S. Sugavanam ◽  
J. Petschulat ◽  
T. Pertsch
Keyword(s):  
Short Range ◽  
Near Field ◽  
Effective Permittivity ◽  
Effective Parameters ◽  
Static Interaction ◽  
Permeability Changes ◽  
Analytical Results ◽  
Permittivity And Permeability ◽  
Random Variation

Influence of the short-range lateral disorder in the meta-atoms positioning on the effective parameters of the metamaterials is investigated theoretically using the multipole approach. Random variation of the near field quasi-static interaction between metaatoms in form of double wires is shown to be the reason for the effective permittivity and permeability changes. The obtained analytical results are compared with the known experimental ones.

Effective parameters of a metamaterial composed of dielectric coated conducting cylindrical rods

2020 ◽  
Vol 12 (8) ◽  
pp. 797-808
Author(s):  
Z. A. Awan ◽  
Hassan Ullah ◽  
Ahsan Ullah ◽  
Afshan Ashraf
Keyword(s):  
Gallium Arsenide ◽  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Effective Permittivity ◽  
Double Negative ◽  
Two Dimensional ◽  
Effective Parameters ◽  
Barium Strontium ◽  
Electric Conducting ◽  
Permittivity And Permeability

AbstractIn the first part, the scattering characteristics of an isolated dielectric coated conducting rod have been investigated. The types of considered coatings for the scattering analysis are realistic materials including barium strontium titanate, magnetodielectric, gallium arsenide, and silicon carbide. It is found that the gallium arsenide coating can be used to significantly reduce the scattering from a thin perfectly electric conducting cylindrical rod at specific observation angles. In the second part, the effective permittivity and permeability of metamaterials composed of two dimensional periodic arrangements of these dielectric coated conducting cylindrical rods have been studied. An increase in the double negative (DNG) bandwidth of a metamaterial composed of barium strontium titanate coated conducting rods has been observed in contrast to the corresponding bandwidth of a metamaterial composed of only barium strontium titanate material rods. Also an additional plasmonic epsilon negative (ENG) bandwidth has been found in case of a metamaterial composed of barium strontium titanate coated conducting rods. It is further studied that the widest ENG, mu negative, and DNG bandwidths exist for a metamaterial composed of gallium arsenide rods.

scholarly journals Time-Domain Studies of General Dispersive Anisotropic Media by the Complex-Conjugate Pole–Residue Pairs Model

2021 ◽  
Vol 11 (9) ◽  
pp. 3844
Author(s):  
Konstantinos P. Prokopidis ◽  
Dimitrios C. Zografopoulos
Keyword(s):  
Time Domain ◽  
Electromagnetic Wave Propagation ◽  
Frequency Dispersion ◽  
Magnetized Plasma ◽  
Dispersive Media ◽  
Complex Conjugate ◽  
Pole Residue ◽  
Permittivity And Permeability ◽  
Arbitrary Frequency ◽  
Difference Time

A novel finite-difference time-domain formulation for the modeling of general anisotropic dispersive media is introduced in this work. The method accounts for fully anisotropic electric or magnetic materials with all elements of the permittivity and permeability tensors being non-zero. In addition, each element shows an arbitrary frequency dispersion described by the complex-conjugate pole–residue pairs model. The efficiency of the technique is demonstrated in benchmark numerical examples involving electromagnetic wave propagation through magnetized plasma, nematic liquid crystals and ferrites.

Dielectric and Magnetic Properties of BaTiO3/NiFe2O4 Composites

2007 ◽  
Vol 336-338 ◽  
pp. 377-380 ◽  
Author(s):  
Jian Hong Shen ◽  
Ji Zhou ◽  
Xue Min Cui ◽  
Yue Hui Wang
Keyword(s):  
Dielectric Constant ◽  
Magnetic Properties ◽  
Solid State ◽  
Spinel Structure ◽  
Initial Permeability ◽  
Solid State Route ◽  
Permittivity And Permeability ◽  
Xrd Studies ◽  
Two Phases ◽  
Conventional Solid State Route

A series of ferrroelectric-ferromagnetic composites were synthesized from BaTiO3 and NiFe2O4 ferrite by conventional solid-state route. XRD studies indicated that the composites comprised of only two phases, BaTiO3 phase with perovskite structure and NiFe2O4 phase with spinel structure. Frequency dependence of permittivity and permeability were also measured. Experimental results showed that the dielectric constant and initial permeability of these composites could be tunable by varying the composition of composites. Thus, these composites can be used for multilayer chips EMI filters.

scholarly journals The Effect of Aging on Precipitates, Mechanical and Magnetic Properties of Fe-21Cr-15Ni-6Mn-Nb Low Magnetic Stainless Steel

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 819
Author(s):  
Changsheng Li ◽  
Kun Li ◽  
Jingbo Dong ◽  
Jinyi Ren ◽  
Yanlei Song
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Stainless Steel ◽  
Magnetic Properties ◽  
Solution Heat Treatment ◽  
Aging Treatment ◽  
Relative Magnetic Permeability ◽  
Coarsening Behavior ◽  
The Matrix ◽  
Coherent Orientation

The effect of aging on the precipitates, mechanical and magnetic properties of Fe-21Cr-15Ni-6Mn-Nb low magnetic stainless steel were investigated. The steel was aged at 550–750 °C for 2 h after solution heat treatment at 1100 °C for 1 h. During the aging treatment, the (Nb, V)(C, N) particles gradually precipitated in the grain, which were coherent or semi-coherent with the matrix. When the aging temperature was beyond 650 °C, the coarsening rate of (Nb, V)(C, N) particles increase rapidly and the coherent orientation between (Nb, V)(C, N) particles and the matrix was lost gradually. Meanwhile, coarse M23C6 was distributed at the grain boundary with chain shape, which was non-coherent with the matrix. The coarsening behavior of (Nb, V)(C, N) precipitates in the grain was analyzed, and the size of the particles precipitated after aging treatment at 650°C for different time was calculated and studied. After aging treatment at 650 °C for 2 h, the yield strength and tensile strength of the stainless steel was 705.6 MPa and 1002.3 MPa, the elongation and the relative magnetic permeability was 37.8% and 1.0035, respectively.

scholarly journals A Design of Functional Layer with Robust Constitutive Parameters for Multilayer Metamaterials

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Zhijie Gong ◽  
Chao Wu ◽  
Quan Li ◽  
Zeyong Wei ◽  
Hongqiang Li
Keyword(s):  
Dielectric Material ◽  
Symmetric Design ◽  
Effective Parameters ◽  
Layer System ◽  
Functional Layer ◽  
Metallic Structures ◽  
Retrieval Technique ◽  
Effective Models ◽  
Incident Cases ◽  
Constitutive Parameters

We propose a functional layer design with robust effective parameters for multilayer metamaterial. The functional layer is consisting of two identical dielectric material layers and one layer of metallic structures sandwiched in between. The symmetric design ensures that, following standard retrieval technique, effective parameters retrieved for a single functional layer in vacuum can be used to characterize its electromagnetic contribution when stacked in a multilayer system. When applied to the fishnet structures, effective parameters of the symmetric functional layer system show great robustness against the varying of the number of layers. The symmetric functional layer design is also investigated on multilayer metamaterials consisting of several layers of different kinds of metallic structures. Transmission and reflection spectra are obtained for real structures and their effective models by finite-differential-time-domain simulation and transfer matrix method calculation, respectively. It turns out that the effective model shows great equivalency to the real structures, and the effective parameters of symmetric functional layer design are robust at both normal and oblique incident cases. Our work provides a practical approach to design and characterize multilayer metamaterials with the well-known effective parameters retrieval technique.

scholarly journals Эффективная диэлектрическая проницаемость анизотропного композита из сфероидных частиц в диэлектрической матрице

2021 ◽  
Vol 47 (23) ◽  
pp. 22
Author(s):  
Б.А. Беляев ◽  
В.В. Тюрнев ◽  
С.А. Ходенков
Keyword(s):  
Numerical Solution ◽  
Integral Equations ◽  
Electromagnetic Waves ◽  
Effective Permittivity ◽  
Transverse Polarization ◽  
Dielectric Matrix ◽  
Anisotropic Composite ◽  
Concentration Dependences ◽  
The Matrix

The concentration dependences of the effective permittivity of an anisotropic composite containing co-directional particles in the form of oblate or elongated ellipsoids of rotation – spheroids – in the dielectric matrix are obtained. The calculation is made by the numerical solution of a system of coupled quadratic and integral equations obtained by a strict modification of the quasi-static Bruggeman theory. It is shown that the traditional (simplified) modification of the Bruggeman theory, widely used for calculating anisotropic composites, gives errors of different signs for the longitudinal and transverse polarization of electromagnetic waves relative to the axis of spheroids. In this case, the dependences of errors on the concentration of particles are non-monotonic, and the extremes observed on them can exceed 100%. Moreover, the position and magnitude of the extremes strongly depend on the ellipticity of the particles, as well as on the contrast of their permittivity with the matrix.

Fundamental properties of surface waves in lossless stratified structures

2010 ◽  
Vol 466 (2120) ◽  
pp. 2447-2469 ◽  
Author(s):  
Guido Valerio ◽  
David R. Jackson ◽  
Alessandro Galli
Keyword(s):  
Surface Waves ◽  
Dispersion Equation ◽  
High Frequency ◽  
Low Frequency ◽  
Layered Structures ◽  
Graphical Solution ◽  
Fundamental Properties ◽  
The Past ◽  
Permittivity And Permeability ◽  
Constitutive Parameters

This paper is focused on dispersive properties of lossless planar layered structures with media having positive constitutive parameters (permittivity and permeability), possibly uniaxially anisotropic. Some of these properties have been derived in the past with reference to specific simple layered structures, and are here established with more general proofs, valid for arbitrary layered structures with positive parameters. As a first step, a simple application of the Smith chart to the relevant dispersion equation is used to prove that evanescent (or plasmonic-type) waves cannot be supported by layers with positive parameters. The main part of the paper is then focused on a generalization of a common graphical solution of the dispersion equation, in order to derive some general properties about the behaviour of the wavenumbers of surface waves as a function of frequency. The wavenumbers normalized with respect to frequency are shown to be always increasing with frequency, and at high frequency they tend to the highest refractive index in the layers. Moreover, two surface waves with the same polarization cannot have the same wavenumber at a given frequency. The low-frequency behaviours are also briefly addressed. The results are derived by means of a suitable application of Foster’s theorem.

IMPACT OF GEOMETRICAL PARAMETERS ON TRANSMISSION PROPERTIES OF CUT-WIRE PAIR STRUCTURES

2009 ◽  
Vol 18 (03) ◽  
pp. 489-499 ◽  
Author(s):  
N. T. TUNG ◽  
Y. P. LEE ◽  
T. X. HOAI ◽  
V. D. LAM
Keyword(s):  
Transfer Matrix Method ◽  
Matrix Method ◽  
Effective Permittivity ◽  
Geometrical Parameters ◽  
Scattering Parameters ◽  
Integration Technique ◽  
Transmission Properties ◽  
Resonance Frequencies ◽  
Permittivity And Permeability ◽  
Magnetic Resonances

We investigate the transmission properties of a metamagnetic structure, the so-called cut-wire pair (CWP), using the transfer-matrix method and the finite integration technique. The electric and magnetic resonances of the CWP structure are demonstrated by the effective medium analyses. The corresponding effective permittivity and permeability are calculated from the complex scattering parameters using the standard retrieval procedure. Importantly, the dependence of transmission properties and resonance frequencies on the periodicities as well as the shape of CWP are systematically examined.

Susceptibility of Chromium?Based Alloys of Transition Elements

1960 ◽  
Vol 13 (2) ◽  
pp. 451 ◽  
Author(s):  
WM Lomer
Keyword(s):  
Magnetic Properties ◽  
Transition Metals ◽  
Specific Heat ◽  
Room Temperature ◽  
Spin Moment ◽  
Transition Elements ◽  
Dilute Solutions ◽  
Spin Orientation ◽  
Local Moments ◽  
The Matrix

The magnetic properties of chromium�based alloys with the transition metals are very varied. Below room temperature it is believed that chromium is antiferrcmagnetic and in this paper we investigate briefly the nature of the influence of this antiferrcmagnetic matrix on the properties of dilute solutions of atoms carrying weIl�defined local moments of their own. It is shown that various anomalies in the susceptibility-temperature relations can be rationalized in terms of a model involving small spin orientation forces arising from the antiferromagnetism. Alloying with vanadium appears to reduce the spin moment on the chromium atoms, but to introduce no localized spins itself. The temperature.independent contribution of cobalt in solution is interpreted in terms of local spins locked by the antiferromagnetism of the matrix. The :results so far obtained suggest that careful specific heat measurements in the range 0--100 OK may disclose very significant anomalies in many of. these alloys.

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