I have recently wandered into the rather vague world of ferrite beads and EMI/EMC suppression. I was advised to find out more about 'coupled ferrite beads' as that apparently happens to better than regular ferrite beads (The person who suggested this doesn't have any resources that could help me). I did a decent amount of surfing around the web as well as in a few journals, but I couldn't find much useful information. If anyone has more information about this matter, any material/paper/articles etc. or any other resources I could make effective use of, could you please share it?