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Ferrite Magnetic-Anisotropy Field Effects on Inductance and Quality Factor of Planar GHz Inductors

By Jaejin Lee, Yang-Ki Hong, Changhan Yun, Woncheol Lee, Ji-Hoon Park, and Soek Bae
Progress In Electromagnetics Research, Vol. 156, 25-35, 2016


Planar gigahertz (GHz) inductors were fabricated based on high crystalline-anisotropy Zn0.13Co0.04Ni0.63Fe2.2O4 (Zn-Co-Ni ferrite) and Ba3Co2Fe24O41 (Co2Z hexaferrite) and characterized for inductance (L) and quality (Q) factor. The planar ferrite inductors show an L of 4.5 nH (Zn-Co-Ni), 5.6 nH (Zn-Co-Ni + low Hk and fFMR Co2Z:), and 4.8 nH (Zn-Co-Ni + high Hk and fFMR Co2Z:) at 2 GHz. The corresponding L-densities are 18.0, 22.4, and 19.2 nH/mm2, which are greater than 16.8 nH/mm2 of the air-core inductor. With respect to the Q factor, the air-core and ferrite inductors exhibit Q factors of 6.7 (air-core), 4.8 (Zn-Co-Ni), 2.8 (Zn-Co-Ni + low Hk Co2Z), and 4.0 (Zn-Co-Ni + high Hk Co2Z) at 2 GHz. The tan δμ of the ferrites caused a reduction in the Q factor. Nevertheless, the high Hk and fFMR Co2Z ferrite inductor demonstrates a higher Q factor than that of the low Hk and fFMR Co2Z inductor. It is, therefore, suggested that high-resistivity, -anisotropy, -magnetization ferrite can produce large L-density and Q-factor GHz inductors.


Jaejin Lee, Yang-Ki Hong, Changhan Yun, Woncheol Lee, Ji-Hoon Park, and Soek Bae, "Ferrite Magnetic-Anisotropy Field Effects on Inductance and Quality Factor of Planar GHz Inductors," Progress In Electromagnetics Research, Vol. 156, 25-35, 2016.


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