Characteristics of Inner-Coil-Type Thin-Film Inductors with no Insulation between Magnetic Films and Conductors

This paper deals with the maximum quality factor in relation to the dimensions of an inner-coil type thin-film inductor with a closed magnetic circuit. We used an equivalent circuit, taking into account of flux distribution and eddy currents in the magnetic film as well as stray capacitances. The proposed inductor yields the maximum quality factor Qmax=32 at f=20 MHz. The quality factor is mainly determined by the iron loss in the magnetic film.