Source: EDN blog
by Kenneth Wyatt, president and principal consultant of Wyatt Technical Services.
The development of stealth aircraft brought about the use of ferrite absorber sheets, which have proven useful for damping cavity resonances at microwave frequencies. Since then, ferrite absorber sheets have become useful at mitigating EMI. Most absorber sheets act as magnetic shields that help “redirect” magnetic fields and become effective at gigahertz frequencies. As my measurements show, some are effective even at much lower frequencies, serving as shielding or absorbers for high-frequency EMI from clock harmonics in the hundreds of megahertz. (more…)