Nano-particles made of onion-like-carbon (OLC) particles are useful for electromagnetic radiation attenuation in the range of about 500 MHz to about 30 THz say inventors Vladimir Kuznetsov Lvovich and Olga Alexander Shenderova. International Technology Center (Raleigh, NC) received U.S. Patent 7,612,138 for the nano-onions which can be blended into a polymer matrix, paints, polytetrafluoroethelyne, resins, polycarbonate, polystyrene, polyurethane, polyimide, acrylics, epoxies, methacrylic, phenolic, silicone, polyester, polystyrene, polyurethane foam (PUF), conducting polymers, vinyl polymers, and many other materials. Nano-diamonds are used to form the OLC which may also encapsulate magnetic nano-particles when desirable.
Electromagnetic (EM) radiation attenuating technology is useful for a wide variety of military and civilian applications ranging from minimizing the Radar signature of a target to EM shielding in consumer electronics. EMI (Electromagnetic Interference) shielding of electronic systems to decrease susceptibility to, and radiation from, EM sources is increasingly important in both civilian and military applications--perhaps particularly at the radio to microwave wavelengths. The usual shielding techniques focus on the use of metals and their composites. Such materials provide shielding due to their conductivity, but they have the disadvantages of heavy weight, limited flexibility and difficulty of matching attenuation requirements with packaging constraints.
The nano-onions can be used as RAM (Radar Absorbing Materials) which is a class of EMAM (ElectroMagnetic Absorbing Material) that is utilized for absorbing Radar signals to hide or disguise a Radar signature. Manufacturing of RAM basically involves the use of compounds causing dielectric or magnetic loss when impinged by electromagnetic waves.