IEEE 299 Testing Standard

IEEE 299 Testing Standard

The IEEE 299 standard was developed to measure the effectiveness of enclosures to provide shielding effects from electromagnetic waves ranging from 9kHz to 18GHz. The enclosure is required to have all dimensions greater than 2 meters. The enclosure can be single-shielded or double-shielded. It can be made of steel, aluminum, copper, shielding fabric, hardware cloth, or metal foils. Its construction can be of bolted, integral, demountable type, or an integral part of any building. 

A parent structure is constructed to house the shielding enclosure. An emitter is placed near the shielding enclosure to irradiate it with EM energy only on a localized surface and a transmitter is placed on the opposite side to receive the signals. Attenuation levels of the enclosure are measured prior to the test. A dynamic range of frequencies are tested and the performance evaluation is compared with the prior results. The ratio of the signal received by the transmitter without shield, to the signal received by the transmitter on placing of the shield is called Shielding Effectiveness (SE). A good shielding enclosure is required to reduce transmission of electric and magnetic fields from outside to inside and vice versa. 

Common Uses of IEEE 299

• To identify efficiency of a shielding material in blocking electric and magnetic fields from entering or leaving any enclosure.

Advantages of IEEE 299:

• Testing is possible for a specific frequency.
• Provides a standard for Electromagnetic Shielding (ES) enclosures.
• EM and RF interference can be avoided using EM testing.

Limitations of IEEE 299:

• The enclosure to be tested is required to have all dimensions greater than 2 meters.
• Cannot use non-standard frequencies.
• Possibility of RF leak around door area while testing.

Industrial Application of IEEE 299

• Telecommunications (mobile networks, printing machines, PCS system)
• Medical (MRI machines)
• Military
• Nautical
• Aviation