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Highly oriented W-type hexaferrites SrNi 2 Sc x Fe 16-x O 27 (SrW, x = 0.70, 0.75, 0.80 and 0.85) are fabricated via ceramic process and magnetic orientation to meet design requirements of self-biased circulators. The orientation degree reaches 0.81 when Sc3+ substitution content x is 0.75. The XRD refinement results in consideration of orientation illustrate the strong c -axis anisotropy texture of SrW. SEM images show significant uniformity in grain growth with c -axis stays vertical to sample plane. Consequently, the corresponding remanence ratio M r /M s reaches as high as 0.92, which is indispensable to reduce low field loss (LFL) as much as possible in the design of self-biased circulators. According to simulation results, the self-biased microstrip circulator based on this SrW material (x = 0.75) realizes ideal functions in circular transmission operating at Ku band. [ABSTRACT FROM AUTHOR]

The grains of oriented W-type hexaferrite BaNi 2 Gd x Fe 16-x O 27 (BaW) where x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5 grew uniformly along their c -axis perpendicular to the sample plane, which meant high remanence ratio of BaW. When Gd3+ substitution content was x = 0.0, the corresponding remanence ratio reached as high as 0.90. When x = 0.2, the oriented BaW simultaneously possessed high saturation magnetization (M s = 58.36 emu/g), high coercivity (H c = 1527 Oe), high remanence ratio (M r /M s = 0.85), relatively low magnetocrystalline anisotropy field (H a = 10,253 Oe) and low ferromagnetic resonance linewidth (Δ H = 624 Oe). These characteristics indicated the material was suitable for the design of self-biased circulator operated at K band. Based on the BaW material, self-biased double Y-junction microstrip circulator was designed and realized well circulatory function at K band. [ABSTRACT FROM AUTHOR]