Microwave properties of diluted composites made of magnetic wires with giant magneto-impedance effect

Acher, O.; Ledieu, M.; Adenot, A.-L.; Reynet, Olivier

doi:10.1109/tmag.2003.816011

Cited by 13 publications

(11 citation statements)

References 27 publications

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“…The dielectric spectra of composites under study are more complicated than that of the samples with impermeable wires [13]. The spectra are similar to that of effective permittivity obtained for a single wire stretched across the section of a coaxial line [15] and consist of two separate absorption peaks affected by magnetic bias. The formation of two peaks of absorption is explained by the interference of the resonance of a wire dipole and of the current-induced ferromagnetic resonance (FMR) of circumferential permeability and is validated numerically.…”

Section: Introductionmentioning

confidence: 51%

“…6 resembles the spectra for a FeCoSiB microwire stretched across a coaxial line [15], although the magnetocapacitance effect is much stronger in the case under study. The reason is that in [15] the frequency of dielectric resonance (∼ 1 GHz) is lower than the FMR frequency (there are no data on the wire permeability in [15], but we suppose from the permittivity spectra that the peak of magnetic loss takes place at ∼ 2 GHz). Therefore, the step of wire impedance takes place at a shoulder of absorption curve, where its effect on the permittivity is small.…”

Section: Computation Of Permittivity As the Function Of Frequency Andmentioning

confidence: 68%

“…5). Therefore, at the resonance frequency the composite with wire sections behaves like a resistive substance, where its equivalent resistance increases with bias, or like a composite similar to one described in [15], where the wire sections are interconnected into a continuous lattice.…”

Section: Comparison Of the Attenuation Range For Particular Screen Stmentioning

confidence: 99%

“…Particularly we consider the absorbing screen of a diluted polymer-bound mixture filled with glasscoated fibers of permeable metal, study the effect of magnetic bias on permittivity spectrum and estimate the range of transparency and reflectivity control by magnetic bias. Contrary to studies on response of a single wire [15][16][17], or lattice of thin continuous wires [15,18] we consider the practicable composites, namely the mats filled with wire sections. The absorption region of the composite is limited by the wire length within approximately 2 ÷ 30 GHz range as the long wires intertwine, while the properties of short ones are unstable [8,18].…”

Section: Introductionmentioning

confidence: 99%

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Microwave Screen With Magnetically Controlled Attenuation

Starostenko¹,

Rozanov²

2009

PIER

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Abstract-The effect of magnetic bias on dielectric spectra of composite sheets filled with Fe or Co-based microwires is studied experimentally and via simulation. The permittivity is measured using a free-space technique within the frequency band from 6 to 12 GHz. The bias is applied either parallel or perpendicular to the microwave electric field; the bias strength varies from 0 to 2.5 kOe. The composites with Fe-based wires reveal a single region of bias dependent permittivity under bias about 800-1000 Oe. The composites with Cobased wires reveal two such regions: the high-field region is close to that of composites with Fe wires, and the low-field region corresponds to the coercive field of Co wires (2-3 Oe). The high-field effect is related to the dependence of ferromagnetic resonance (FMR) parameters on bias; the low-field effect is related to the rearrangement of the domain structure of Co-based wires. The interference of magnetoimpedance and dipole resonance is analyzed, revealing the effects off wire length, diameter, parameters of magnetic resonance and composite structure. The results are considered in view of application to the problem of controlled microwave attenuation. Simulation shows that the narrower is the FMR spectrum and the higher is the admissible loss of a sheet in a transparent state, the wider is the dynamic range of attenuation control. The attenuation range of a lattice of continuous wires is smaller than that of a screen with identical wire sections, where the magnetoimpedance effect is amplified resonantly. At 15 GHz frequency the strength of the bias switching opaque sheet with Fe-based wires to the transparent state is about 2000 Oe. For 3 dB admissible loss, the range of attenuation control about 10 dB is feasible in a composite with aligned wire sections. If the aligned sections are distributed regularly, the loss in a transparent state is about 1 dB lower.

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Section: Introductionmentioning

confidence: 51%

Section: Computation Of Permittivity As the Function Of Frequency Andmentioning

confidence: 68%

Section: Comparison Of the Attenuation Range For Particular Screen Stmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Microwave Screen With Magnetically Controlled Attenuation

Starostenko¹,

Rozanov²

2009

PIER

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“…Hence, we will assume E V E loc in our analysis. For the diluted plasma, the average value of electric displacement D V is obtained as [21,22]:…”

Section: Formulation Of the Problemmentioning

confidence: 99%

A Novel DNG Medium Formed by Ferromagnetic Microwire Grid

Kumar¹,

Kalyansundaram²

2017

PIER B

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Abstract-Effective permittivity and permeability of a medium consisting of an infinite number of ferromagnetic microwires are evaluated in this paper. Analysis is carried out with the help of local and average fields inside a unit cell. In the literature, effective permittivity of the microwire grid is obtained by assuming the grid as an impedance loaded surface. The analysis is applicable only for the case of T M z polarized normally incident wave. Proposed analysis enable us to evaluate all the three diagonal components of effective permittivity and permeability for arbitrarily incident uniform plane wave having arbitrary polarization angle. Numerical results are obtained through MATLAB, and a comparison is done with the results available in the literature for validation. Numerical results have shown a DNG like behaviour of the medium for a T M z polarized incident wave.

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