US Patent 7612138 - Carbon nano-onion EMI shielding

http://www.freepatentsonline.com/7612138.html

One of the earliest proposed applications of fullerene (and later carbon nanotube) composites was in the formation of lightweight electromagnetic shielding. This patent from the International Technology Center teaches another variety of nanocomposite EMI shielding based on onion-like carbon particles. Claim 1 reads:

1. An electromagnetic radiation attenuating material for attenuation of electromagnetic radiation in at least a portion of the frequency range of approximately 500MHz to 30 THz, comprising:

a binding matrix; and

an operative quantity of electromagnetic radiation attenuating nano-particles suspended in the binding matrix, wherein, the electromagnetic radiation attenuating nano-particles comprise onion-like-carbon (OLC) particles.