Disclosed is a planar inductor which has spiral conductor coil means sandwiched between ferromagnetic layers with insulating layers interposed therebetween. The spiral conductor coil means is formed of two spiral conductor coils of the same shape arranged flush with and close to each other. Moreover,...http://www.google.fr/patents/US4959631?utm_source=gb-gplus-shareBrevet US4959631 - Planar inductor
