Lam Research Corporation
Ferrite cage RF isolator for power circuitry

Abstract:

RF isolation for power circuitry includes one or more ferrite cages surrounding a pair of coils, one coil connected to power input, and the other coil connected to a load such as a heater. The ferrite cage provides universal isolation for the coils, avoiding the necessity of specially tuned filters or more complicated coil arrangements. A pair of dielectric discs support respective coils. In one aspect, the ferrite cage is constituted by ferrite pieces which fan out from a central portion of the dielectric discs and are connected at an outer periphery of the dielectric discs, and at the central portion of the dielectric discs. In one aspect, the fanned-out ferrite pieces comprises either manganese-zinc or magnesium-zinc ferrites, and the ferrite pieces connecting the fanned-out ferrite pieces comprise nickel-zinc ferrites.