Inductance Evaluation of CPW with Co-Zr-Nb Film Using Magnetic Circuit Analysis

Inductance of an on-chip transmission line with a magnetic film-type noise suppressor is quantitatively evaluated based on magnetic circuit analysis to develop design guidelines. A Co85Zr3Nb12(Co-Zr-Nb) film with uniaxial anisotropy deposited on a coplanar waveguide (CPW) was used as a test bench, and a magnetic circuit model was developed with cross-sectional size and material parameters. The magnetic circuit analysis included the ferromagnetic resonance (FMR) frequency shift caused by an additional demagnetizing field due to the presence of the narrow CPW. The inductance calculated using the reluctance around the signal line was almost the same as measured values. Results of this study indicated that the frequency characteristics of the inductance were mostly affected by the real part of the complex permeability considering the demagnetizing field.