WG299 - Working Group for Electromagnetic Shielding Enclosures

Maria Sarto

Superseded by IEEE Std 299-2006. Uniform measurement procedures and techniques are provided for determining the effectiveness of electromagnetic shielding enclosures at frequencies from 9 kHz to 18 GHz (extendable to 50 Hz and 100 GHz, respectively) for enclosures having no dimension less than 2.0 m. The types of enclosures covered include, but are not limited to, single-shield or double-shield structures of various construction, such as bolted demountable, welded, or integral with a building; and made of materials such as steel plate, copper or aluminum sheet, screening, hardware cloth, metal foil, or shielding fabrics.

This standard provides uniform measurement procedures for determining the shielding effectiveness of electromagnetic (EM) shielding for a variety of enclosures and boxes having all dimensions between 0.1 m and 2 m in the radio frequency range not addressed by IEEE Std 299(TM)-2006. This standard is divided into two parts: Part I - 0.75 m to 2 m and Part II - physically small (< 0.75 m) but electrically large enclosures. In addition to a number of annexes aiding the measurement of shielding effectiveness of these enclosures, Annex I addresses physically small and electrically small enclosures, and Annex J addresses electrically small enclosures in reverberation chambers. Problems occurring in the testing of small enclosures having linear dimension less than 2 m are very different from determining the shielding effectiveness of large rooms and broad depending on the actual size of the enclosure itself. A number of other annexes are included that address rationale, mathematical formulas, selection of measurement techniques, preliminary measurement and repairs, wall-mounted monopoles, impedance mismatch correction, and using isolated monopoles in outer reverberation chambers.