IEEE 299-2006: Measuring The Effectiveness Of Electromagnetic Shielding Enclosures

IEEE 299-2006 is a standard for evaluating the shielding effectiveness of materials used in the construction of electronic and electrical equipment. The standard provides a methodology for conducting shielding effectiveness tests and evaluating the results to determine the ability of the materials to reduce the amount of electromagnetic interference (EMI) that enters or leaves electronic devices.

IEEE 299-2006 is a standard for shielding effectiveness testing that was established by the Institute of Electrical and Electronics Engineers (IEEE). This standard outlines the procedures for evaluating the effectiveness of electrical shielding materials and systems. It is used to determine the level of protection provided by the shielding material against electromagnetic interference (EMI).

Summary of IEEE 299 Shielding Effectiveness Testing

IEEE 299-2006 provides guidelines for performing shielding effectiveness testing for both single and multi-layer shielding systems. The standard specifies the frequency range, test method, and measurement procedures for evaluating the shielding effectiveness of various materials, including conductive elastomers, metal screens, metal foils, and metal fabrics.

In addition to the testing procedures, IEEE 299-2006 also provides guidelines for the interpretation of the test results and recommendations for the reporting of the shielding effectiveness data. The standard also includes a procedure for evaluating the reliability of the test results, including the measurement uncertainty of the testing equipment and the repeatability of the test procedures.

The use of IEEE 299-2006 is mandatory for evaluating the shielding effectiveness of products used in military and aerospace applications, and is widely used in other industries, including telecommunications, medical equipment, and computer electronics. The standard is reviewed and updated regularly to ensure that it remains relevant and up-to-date with the latest developments in shielding technology.

It is important to note that IEEE 299-2006 testing must be conducted in a controlled environment and using properly calibrated test equipment. The equipment must be able to accurately measure the levels of EMI present in the test environment and the results of the testing must be recorded and analyzed in accordance with the procedures specified in the standard.

Scope of IEEE 299 Regulatory Compliance Testing

IEEE 299-2006 is an essential tool for anyone involved in the design, manufacture, or evaluation of electronic equipment and systems. By providing a standardized methodology for evaluating the shielding effectiveness of materials, the standard helps ensure that electronic devices are protected from EMI and operate reliably in the presence of electromagnetic interference.

Testing to IEEE 299 requires placing transmitting and receiving loops approximately 0.3 m from the respective shielding barrier. The generator output is maintained at the level used during the reference measurement and is applied at each frequency and location.

During all low-frequency measurements, one loop remains in a fixed position and the second loop is repositioned and displaced to seek a worst-case measurement. The maximum indication of the detector reading shall be used for determining the shielding effectiveness.

IEEE 299 Test Procedures

Similar to other shielding effectiveness standards, the IEEE 299-2006 standard is specifically for enclosures. Any classification of the enclosure may apply. However, the enclosure must serve a purpose to shield from exterior electric or magnetic fields or protect the environment around itself from the effect of an interior electric or magnetic field.

The testing process outlined in IEEE 299-2006 involves several steps, including:

  1. Preparation of the shielding material: A representative sample of the shielding material is selected and its physical characteristics are measured. A test setup is also created to allow the material to be evaluated in a controlled environment.
  2. Conducted emissions testing: This test measures the amount of EMI that is conducted through the shielding material and into the electronic device. It involves applying an EMI source to the material and measuring the level of interference that enters the device.
  3. Radiated emissions testing: This test measures the amount of EMI that is emitted from the electronic device and passes through the shielding material. It involves applying an EMI source to the device and measuring the level of interference that passes through the material.
  4. Immunity testing: This test measures the ability of the shielding material to protect the electronic device from external sources of EMI. It involves applying an external EMI source to the material and measuring the level of interference that enters the device.
  5. Evaluation of results: The results from the conducted emissions, radiated emissions, and immunity testing are evaluated and compared to the acceptance criteria specified in IEEE 299-2006. The overall shielding effectiveness of the material is also assessed.

The enclosure is generally constructed of metal with guidelines for continuous electrical contact between joining panels (i.e., doors). Examples for specific enclosures include single-shield or double-shield structures of various construction (i.e., bolted demountable, welded, or integral with a building) made of materials (e.g., steel plates, copper/aluminum sheets, screening, hardware cloth, metal foil, or shielding fabrics).

The required frequency range for the shielding effectiveness test must include the span from 9 kHz to 18 GHz. Nonetheless, this can be extended to cover frequencies down to 50 Hz and up to the maximum up to 100 GHz.

The testing procedures specified in IEEE 299-2006 are based on a transfer impedance measurement method. This method involves applying a voltage signal to the shielding material and measuring the current that flows through the material. The shielding effectiveness of the material is then calculated from the ratio of the applied voltage to the resulting current.

Expert IEEE Shielding Effectiveness Testing

Keystone Compliance has the capabilities to test any size of enclosure to IEEE-299. We have tested large items such as entire on-site installation buildings and small items that can be easily transported to our lab. In addition to IEEE 299 testing, Keystone Compliance has an extensive test scope including IP code, vibration, wireless, and packaging.

Are you ready to partner with Keystone Compliance to determine the shielding effectiveness of your product when tested to the requirements of IEEE 299-2006? Let’s get started!

Diagram of IEEE-299 Testing

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