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MATERIAUX MAGNETO-DIELECTRIQUES A BASE DE NANOFERRITES POUR LA MINIATURISATION D'ANTENNES IMPRIMEES

Actes de la Conférence JCMM 2010 03/2010;
Source: OAI

ABSTRACT Les travaux de recherche pour la miniaturisation d'antennes, utilisant de nouveaux matériaux, se sont intensifiés ces dernières années, et notamment avec l'utilisation de matériaux possédant des propriétés magnétiques. La miniaturisation des antennes imprimées est rendue possible en chargeant le volume de l'antenne avec des matériaux à haute permittivité [ ], ferroélectriques [ ], ferromagnétiques [ ], magnéto-diélectriques [ , , ], etc. Plus traditionnellement, les diélectriques présentant une permittivité élevée ont été employés pour diminuer les dimensions physiques de l'élément rayonnant [ ]. Les problèmes souvent rencontrés avec les substrats de haute permittivité sont, par exemple, la dégradation de la bande passante et du gain et donc l'efficacité de l'antenne. L'utilisation de matériaux magnétiques serait une solution intéressante pour la miniaturisation d'antennes sans dégrader les performances grâce à la valeur importante de la perméabilité. Or à ce jour, malgré les progrès technologiques importants réalisés sur les matériaux ferrites doux, ceux-ci sont utilisés principalement en basse fréquence pour la réalisation de dispositifs non réciproques (circulateurs, isolateurs) ou de circuits accordables (filtres, déphaseurs...). Dans la bande UHF, leurs pertes élevées, liées à une contribution des déplacements de parois séparant les domaines magnétiques, excluent leur utilisation comme substrat d'antennes imprimées. Dans ce travail, nous développons un nouveau matériau magnéto-diélectrique pour l'application antennaire. Ses performances sont comparées à celles d'un matériau disponible dans le commerce.

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