The standard has extended to upper frequencies from 2,5 to 5,925 GHz to keep up with technological advancements and improve overall quality. Another critical change in edition 5 is section 4.3.4, which describes that the performance of the absorption material shall be greater than or equal to 6dB from 70MHz – 5,925GHz. This is a significant change compared to edition 4, where the upper frequency was 2.5GHz.

Partial absorber lining
Why is this important? Many automotive component test chambers are built with a so-called partial absorber lining, which means all walls and ceilings are covered with ferrite tiles. Still, roughly half of these surfaces are also covered with hybrid absorbers. The absorbers are typically installed around the test table in a ‘horse-shoe’ layout on the walls and ceiling. Moving the 6dB reflectivity requirement from 2.5 to 5,925 GHz means that surfaces covered with ferrite tiles only, the other half of the chamber, no longer comply with this section of CISPR25 ed.5.

Testing and upgrading
If you already have a chamber, we can upgrade it by installing hybrid absorbers to cover the walls and ceiling completely. Additionally, if you need to have your chamber (also called ALSE) validated according to Annex I (long wire test method), we can perform that test for you. Comtest Engineering has the necessary equipment and skilled test engineers to conduct the test and demonstrate compliance.

One example of this proactive approach was with our client, Marjan Mak, from SIQ Ljubljana in Slovenia – the leading EMC laboratory in the region. “When we purchased a new chamber from Comtest last year, they informed me about the new CISPR25 requirements and offered an alternative design that met all the new requirements. As a top compliant EMC service provider, it is essential to be fully compliant ourselves. Meanwhile, the Comtest team upgraded our existing chamber to make it future-proof and 100% compliant.”

If you’re a professional unsure about the adequacy of your materials, we’re happy to offer a quick consultation and provide you with the necessary CISPR25 validation test via one of our technical consultants, Marc Le Roy, Hanneke Mertens – van Veen or Uliana Trucchi.