Design and engineering of a large shielded semi-anechoic chamber meeting the volumetric NSA requirements at 3 and 10 m transmission length

A large shielded semianechoic chamber meeting the validation requirements for alternative test sites as specified in ANSI C63.4-1991 (and equivalent CISPR and EN drafts) has been realized at the CESI EMC Laboratory, Milan, Italy. The authors discuss the problems of integration in a preexisting building of the semianechoic performance with all the hardware that makes the site practically useable, such as suitable lighting, large doors, and vehicle-size turntable. Special hollow pyramidal absorbers of 2.5 m thickness were designed to give the required reflection attenuation