Abstract: A magnetodielectric composition is made of flakes of magnetic material dispersed in a binder at a concentration of about 30 to 60%. The flakes consist of a thin film of magnetic material or alternating thin film layers of magnetic material and insulating material. The flakes do not include a substrate. Consequently, the effective volume concentration of magnetic material in the composition is far greater than with other magnetodielectric materials. The binder is selected to provide a fluent composition for application like paint or a setable composition for formation of sheets and molded structural elements. In use, the composition is effective to reduce the size, weight and volume of electrical devices such as antennas, delay lines, phase shifters and other devices requiring interaction with and/or magnetic response to high frequency radiation.

Abstract: An article (22) is coated with a cermet coating (20) by first roughening and oxidizing the surface to be coated. A mixture is formed of a metallic powder having a mean particle size of less than about 5 micrometers, and a ceramic powder having at least some of the particle of a size less than the mean particle size of the metallic powder. The mixture of the metallic powder and the ceramic powder desirably has a coating coefficient of thermal expansion of about that of the article coefficient of thermal expansion after firing. The mixture of metallic and ceramic powders is slurried and applied to the prepared surface (24) of the article (22), preferably by spraying. The coated article is heated to an intermediate temperature to vaporize the carrier liquid, and thereafter to high temperature to sinter the coating.

Abstract: A method and apparatus for providing a switchable electromagnetic interference (EMI) barrier. The method protects an object against electromagnetic radiation, through the steps of: providing an object to be protected from electromagnetic radiation; placing a barrier sheet adjacent to the object, the sheet being opaque to radiation when exposed to light; directing the light against the sheet when a barrier to the radiation is desired; and extinguishing the light when passage of the radiation through the sheet is desired. One embodiment is a switchable electromagnetic radiation barrier system that includes a photoresistive sheet interposed between a source of electromagnetic radiation and an object to be protected from the radiation. This sheet is opaque to the radiation when exposed to light of a selected visible intensity range. A light source adjacent to this sheet directs the light against the sheet.