CISPR25 Edition 5 & partial absorber lining

What are the design criteria for CISPR25 towards absorber lining as per the latest standard version? CISPR 25 was initially published in 1995. The 5th edition, published in 2021, significantly expanded the category of receivers by including new technologies such as Wi-Fi, V2X, navigation, and more.

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.

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Upgrading an EMC chamber with new absorbers on old tiles

Can you upgrade an EMC chamber and keep the old, glued ferrite tiles? “It’s possible”, says Uliana Trucchi, one of our technical consultants. “Say you want to replace your old absorbers because you need to meet performances over 1GHz, and you wish to keep the ferrite tiles because they are glued to the chamber’s walls and ceiling. That is exactly what the people from Nemko in Germany asked us for the chamber upgrade in the photo.”

Our services include maintenance and validated testing. We recommend that both are executed by authorized personnel only. Our expert teams can perform preventive maintenance on RF-shielded doors, mode-stirrer systems, and positioning equipment such as turntables. We also offer validation services to see if your EMC test chamber or RF-shielded room still functions within its intended limits and avoiding unexpected down-time or product recalls at the same time.

Our services include maintenance and validated testing. We recommend that both are executed by authorized personnel only. Our expert teams can perform preventive maintenance on RF-shielded doors, mode-stirrer systems, and positioning equipment such as turntables. We also offer validation services to see if your EMC test chamber or RF-shielded room still functions within its intended limits and avoiding unexpected down-time or product recalls at the same time.

A shielded room can perform conducted emission and immunity EMC measurements, eliminating harmful external influences, leading to more accurate and consistent test results. Being a Faraday cage, a shielded room will not only improve test results but will also form an excellent aid in protecting information and essential hardware. Comtest can assist governments, the military, financial institutions, and large corporations in protecting what matters most in critical situations. We offer the highest quality, sensitivity, and security before, during and after working with you.

A shielded room can perform conducted emission and immunity EMC measurements, eliminating harmful external influences, leading to more accurate and consistent test results. Being a Faraday cage, a shielded room will not only improve test results but will also form an excellent aid in protecting information and essential hardware. Comtest can assist governments, the military, financial institutions, and large corporations in protecting what matters most in critical situations. We offer the highest quality, sensitivity, and security before, during and after working with you.

Comtest has been building high-quality antenna test ranges for more than 20 years. We are dedicated to putting our experience to work for you, turning any problem you might have into a customized test solution. As for researching and developing your products, we know speed and return on investment are very important. That’s why we ensure your project is delivered on schedule, on budget and exactly as ordered.

Comtest has been building high-quality antenna test ranges for more than 20 years. We are dedicated to putting our experience to work for you, turning any problem you might have into a customized test solution. As for researching and developing your products, we know speed and return on investment are very important. That’s why we ensure your project is delivered on schedule, on budget and exactly as ordered.

Comtest offers semi and full anechoic chambers that shield almost 100% of ambient emissions and reflect minimal internal radiation. We deliver or build your custom test chamber at your location, depending on what size chamber you need. If you tell us your challenges, we’ll offer a tailored turnkey solution from design to installation, including upgrades and yearly certifications.

We are committed to helping you achieve the best EMC testing possible. 

Comtest offers semi and full anechoic chambers that shield almost 100% of ambient emissions and reflect minimal internal radiation. We deliver or build your custom test chamber at your location, depending on what size chamber you need. If you tell us your challenges, we’ll offer a tailored turnkey solution from design to installation, including upgrades and yearly certifications.

We are committed to helping you achieve the best EMC testing possible.