A new planar inductor with ring-connected magnetic core

A planar inductor employing a ring-connected magnetic core has been devised. By connecting small planar ring cores in a matrix array, the magnetoresistance of the magnetic circuits in the core is reduced, and high inductance, which is about 1.5 times that of the conventional ring-core inductance, is achieved. By exciting the core with two coils arranged orthogonally, the stray capacitance, which restricts the upper limit of the useful frequency band, is decreased. The inductor is suitable for a microinductor operating at high frequency. The ring-connected core can be also used as a transformer with high coupling coefficient and low stray capacitance