Structure of Magnetic Core in the Thin Film Inductor

Thin film inductors with a magnetic strip array core and with a planar core are discussed. The inductance per unit volume is comparable for the two, and increases with increasing magnetic core volume in the low frequency range for both. The inductance and Q at high frequencies are increased by using a planar core. On the other hand, the maximum Q and the frequency at which it occurs both increase with decreasing magnetic core thickness. Low eddy current losses and a large magnetic core volume are needed for high inductance and Q values at high frequencies. Multilayer planar cores in which the thin magnetic layer is laminated with insulators are useful as thin film inductors in high-frequency operation.