Using Ferrite Beads as an SGEMP Reduction Tool

Recent studies of SGEMP circuit hardening techniques indicate that the ferrite bead is an ideal component for these purposes. However, to many designers, its ability to introduce high-frequency losses into a circuit is still widely misunderstood. In this paper, the basic attenuation properties of ferrite shielding beads are discussed in detail, as well as other important parameters and environmental considerations which might affect their usefulness in a SGEMP reduction application. Analytical techniques to predict insertion loss ratios in circuitry with beads are developed, and the effects of gapping and dc bias on the effective impedance levels presented by ferrite beads are examined.