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Integration of High‐Frequency M‐Type Hexagonal Ferrite Inductors in LTCC Multilayer Modules
Author(s) -
Bierlich Silvia,
Reimann Timmy,
Barth Stefan,
Capraro Beate,
Bartsch Heike,
Müller Jens,
Töpfer Jörg
Publication year - 2015
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/ijac.12512
Subject(s) - materials science , ferrite (magnet) , ceramic , microstructure , inductor , crystallite , hexagonal crystal system , composite material , optoelectronics , metallurgy , electrical engineering , crystallography , chemistry , voltage , engineering
Monolithic hexagonal BaCo 1,3 Ti 1,3 Fe 9,4 O 19 ferrite multilayers sintered at 900°C exhibit a fine‐grained microstructure with permeability of μ′ = 16 and a resonance frequency f r ≥ 1 GH z. Co‐firing of hetero‐laminates of ferrite with CT 700 glass–ceramic LTCC tapes and with polycrystalline zinc titanate ( ZT ) LTCC tapes was studied. Co‐firing at 900°C of ferrite/ CT 700 leads to multilayers with cracks caused by substantial thermal expansion mismatch. Co‐fired ferrite/ ZT multilayer laminates exhibit a permeability of μ′ = 16 and do not show any defects. Hexagonal ferrite multilayer inductor elements were integrated into ZT ‐based multilayer LTCC modules and co‐fired at 900°C with Ag metallization.