The number of stirrer positions vs power

Testing time is valuable, so this post provides tips on optimising the number of stirrer positions in your reverberation chamber to fit your budget and test requirements. “There is a delicate balance between the number of stirrer positions and the amplifier power for a given reverberation chamber,” explains our R&D Consultant, Dimitrios Barakos. By collaborating with EMC test solution provider Rohde & Schwarz, we aim to find the most efficient solution for our clients. “

Dimitrios: “The lowest frequency of operation dictates the chamber size and should be considered during initial design. The amplifier power required to generate a particular field level for the chosen size of the chamber can be reduced by increasing the number of stirrer steps. However, a minimum number of stirrer steps is required to achieve a certain field uniformity. Therefore, we prefer to design a chamber with the lowest usable frequency in mind that can accommodate more stirrer steps than required, with the possibility of reducing the stirrer steps in the future. This approach will help reduce test time but will require larger amplifier power. Upgrading the amplifier is easier than upgrading the chamber size. Building and calibrating a new chamber takes a lot of time; as you know, time is money.”

Rohde & Schwarz’s EMC Solution Specialist for the Nordics, Martin Randrup Villadsen, advises, “The balance of amplifier power and stirrer steps can impact investment cost and test time. A good compromise can be to allocate a budget for an amplifier upgrade if needed. Rohde & Schwarz’s family of configurable broadband amplifiers with scalable frequency and power levels make this easy.”

We know a perfect solution might sound complicated. So, to help, you can always contact one of our technical consultants, Vincent van de Vrie, Hanneke Mertens – van Veen, Uliana Trucchi, or Marc Le Roy, to explore a sustainable solution for your needs.

In the video: the LUF200 reverberation chamber with a dual-stirrer setup for close-loop testing (fast-stirring) as per ISO-11451-5  at the Rohde & Schwarz Asia-Pacific hub in Singapore.

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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.

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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.

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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.

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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.