The use of a FARADAY chamber avoids the propagation of the Electromagnetic field in the vicinity.

Therefore, the apparatus outside of the chamber is not affected. Unfortunately, reflections from the FARADAY chamber walls lead to stationary waves. Consequently, the field within the FARADAY chamber is not uniform.

Absorbers are used to avoid all reflections in the FARADAY chamber, which is then called an "Anechoic chamber".