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Caractérisation et application de matériaux composites nanostructurés à la réalisation de dispositifs hyperfréquences non réciproques

Abstract : Anisotropic properties of magnetized ferrites are commonly at the basis of nonreciprocity in microwave devices, e.g., circulators and isolators. However, ferrites are not the best suited materials for such applications, due to their moderate saturation magnetization and high-sintering temperature needed during their manufacturing process. Consequently, research laboratories tend to propose substitute materials. To achieve an optimized performances-nonreciprocal device based on such a magnetized material, the exact knowledge of its tensorial permeability is required over a broad-frequency range. The originality of this work is twofold. At first, a measurement technique enabling the noniterative and broad-band (up to 6-7 GHz) determination of the permeability tensor components (µ, k) of magnetized or demagnetized magnetic materials has been developed. The measurement cell used is composed of a nonreciprocal strip transmission line. The major advantage of this new technique is to permit to study the material behavior in the same environment as microwave devices (« in-situ » characterization method). Then, the measurement capability has been employed to demonstrate the field-induced anisotropy of nanocomposite samples. Based on a comparison with a standard ferrite, this original magnetic anisotropy of magnetized nanophases has been exploited to investigate the design of an optimum an low-cost resonance microwave isolator.
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https://tel.archives-ouvertes.fr/tel-00004319
Contributor : Stéphane Mallégol <>
Submitted on : Monday, January 26, 2004 - 3:15:24 PM
Last modification on : Wednesday, October 14, 2020 - 3:52:14 AM
Long-term archiving on: : Friday, April 2, 2010 - 8:04:52 PM

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  • HAL Id : tel-00004319, version 1

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Stéphane Mallégol. Caractérisation et application de matériaux composites nanostructurés à la réalisation de dispositifs hyperfréquences non réciproques. Autre. Université de Bretagne occidentale - Brest, 2003. Français. ⟨tel-00004319⟩

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