volume | PIER Journals

Abstract

Planar gigahertz (GHz) inductors were fabricated based on high crystalline-anisotropy Zn_0.13Co_0.04Ni_0.63Fe_2.2O₄ (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.

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Dr. Jaejin Lee

Prof. Yang-Ki Hong

Dr. Changhan Yun

Dr. Woncheol Lee

Dr. Ji-Hoon Park

Dr. Soek Bae