Toroid microinductors using segmented magnetic cores

A new approach to toroid microinductors with magnetic core is introduced. The core consist of a segmented metal-polymer composite. The investigations aim at fulfilling the demands of small size, high inductance, high operation frequency, and adequate quality factor required for modern mobile communication electronics. A torodial inductor was designed using HFSS and realized in thin-film technology with various core designs to avoid eddy currents and minimize parasitic capacitance. The magnetic core is formed by a segmented multilayer of sputter deposited soft magnetic FeCoBSi, which was deposited in a special way to realize a crossed anisotropy. The terminal impedance Z11 is determined from measured and simulated S11 parameters. Results show the unique properties of the inductors. The simulated and measured parameters are in reasonable agreement.