Filters

Settings

Now showing1 - 2 of 2
  • Some of the metrics are blocked by your 
    consent settings
    Item type:Publication, Access status: without files ,
    Hexagonal ferrites for self-biasing circulators integrated in LTCC microwave modules
    (Elsevier, 2024-10-01)
    Heidenreich, Manuel
    ;
    Schur, Johannes
    ;
    Müller, Jens
    ;
    Gitzel, Wanja Mario
    ;
    Jacob, Arne
    Next-generation microwave LTCC modules for satellite communication systems require the integration of passive components including circulators to manipulate electromagnetic signals at high frequency. Substituted M-type hexagonal ferrites (Ba/Sr)ScxFe12−xO19 are applied as self-biasing microwave magnetic materials at frequencies of about 30 GHz. The ferrites are integrated into LTCC multilayer devices as sintered drop-in bulk samples. Sintered ferrites with preferential orientation of grains were fabricated by compaction of powders in a magnetic field and sintering at 1300 °C. Alternatively, screen-printed ferrite films were dried in an external magnetic field, and cofired at 900 °C. The magnetic texture of the ferrites is characterized using XRD, EBSD, and magnetic measurements. Integrated Y-type circulators were tested and exhibit non-reciprocal behavior. This indicates that hexagonal ferrites are promising candidates for self-biasing circulators embedded in LTCC microwave modules operating at Ka-band frequencies at around 30 GHz.
    Publicationtype: Journal Article
      56
  • Some of the metrics are blocked by your 
    consent settings
    Item type:Publication, Access status: without files ,
    Low-temperature sintering and magnetic properties of Sc- and In-substituted M-type hexagonal barium ferrites for microwave applications
    (Elsevier, 2017-02-01)
    Bierlich, Silvia
    ;
    Gellersen, Frauke K. H.
    ;
    Jacob, Arne
    ;
    Töpfer, Jörg
    Partial substitution of Fe3+ by Sc3+ or In3+ in M-type ferrite is an effective method to tailor their anisotropy field and resonance frequency. BaMexFe12-xO19 with Me = Sc and In (0 ≤ x ≤ 2) was synthesized by the mixed-oxide route. XRD revealed a continuous increase of the hexagonal lattice parameters with substitution rate x. Both, the saturation magnetization and coercivity at room temperature are reduced with x. The ferromagnetic resonance frequency decreases from 48 GHz at x = 0 to 30 GHz at x = 0.5 for Sc-substituted ferrites. For In-substitution, a smaller reduction of the resonance frequency with x is observed, e.g. to 37 GHz at x = 0.5. Addition of BBSZ glass allows sintering at 900 °C. Low-temperature fired samples exhibit ferromagnetic resonance at the same frequencies and represent promising materials for self-biased microwave components for integration into LTCC multilayer modules.
    Publicationtype: Journal Article
      74