RF shielded structures against A - EMP /electromagnetic pulse/, B - Interference to frequencies up to 40 GHz

Shielding structures to protect against nuclear EM pulse and RF interference up to 40 GHz are described; attention is given to shielding modifications for existing buildings, welded metallic liners, and prefabricated structural systems. The prefabricated structural systems will not degrade over the lifetime of a building in which they are installed, and will provide 120 dB attenuation up to 10 GHz and 100 dB attenuation above 10 GHz. Design of structural joints and waveguide vents to ensure protection against interference up to 40 GHz is also discussed.