Tunable on-chip inductors up to 5 GHz using patterned permalloy laminations

This paper presents the design criteria, processing techniques, and measurement results for an on-chip inductor that uses a permalloy (Ni
₈₀
Fe
₂₀
) film to achieve a tunable reactance. Eddy currents and ferromagnetic resonance are suppressed in the thin permalloy film using patterning and laminations to enable operation in the RF range. Measurements results show a 40% increase in inductance, a 15% tuning range, and a Q between 5 and 11 up to 5 GHz