Anechoic Chambers Information

Anechoic chambers are specialized chambers designed for electromagnetic or sound waves. They have specialized walls to absorb and reflect waves of electromagnetic radiation. Acoustic anechoic chambers are soundproof and used for testing applications. They are usually constructed with cement or brick walls to keep outside sound from entering the chamber. Inside, the chamber is lined with fiberglass wedges to absorb the sound waves. Anechoic chambers that are used to study or test electromagnetic interference (EMI) are lined with an absorbent material, such as carbon-impregnated foam shaped into pyramids. The pyramidal shape acts to resist and dissipate the electromagnetic waves. EMI testing is done in anechoic chambers to analyze the properties of antennas and other electronics that are susceptible to radio or microwave interference.

Anechoic chambers range from small compartments to chambers as large as aircraft hangars. The size of an anechoic chamber depends on the size of the objects to be tested and the frequency range of the radio or microwave signals used. Radio frequency interference (RFI) is the unwanted reception of radio signals and can be problematic to the other electronic equipment onboard aircraft and other vehicles. Radio frequency interference sources include lightning, electrical equipment, fluorescent lighting, cell phones, and transmitting equipment from radio stations. RFI testing helps determine which frequencies affect particular electronic systems and provide clues to mitigating the risks to communication devices or developing measures to counter the interference.

Electromagnetic compatibility (EMC) measures the ability of an electronic device or system to function in its intended electromagnetic environment to work efficiently without error. Electromagnetic compatibility (EMC) issues include interference to radios produced by power lines, or the interference fluorescent lighting produces in computer monitors. Anechoic chambers used to conduct EMC testing monitor a device’s electromagnetic emissions and their potential interference to other devices, as well as the tested devices immunity or susceptibility to stray radio or microwave signals.