
Exchanging Fast-stirring and ISO 11451-5 knowledge in Japan
Last week, our consultants, Hanneke van Veen and Dimitrios Barakos, visited seven companies in Japan with our friends from Microwave Factory to help companies implement the closed-loop power control (fast stirring) reverb method as per the ISO11451-5 test standards.
Most RF/MW engineers, who often work in anechoic chambers, have noticed a layer of fine black dust inside their chambers and on their clothes and hands. Some engineers even keep an additional set of work clothes for use within the anechoic chamber due to this issue.
So, how did this happen, and how did they solve it? Rik de Groot, the owner of Dutch Microwave Absorber Solutions (DMAS), explains: “Traditional polyfoam is impregnated with high-loss dielectric material. Over time, depending on the chamber climate conditioning, the absorbers become brittle and leak the fine black particles. These particles are potentially hazardous and a nuisance for the lab working environment, but may also destabilise the absorbers’ RF performance.”
Following the successful introduction of the hybrid EMC absorber in 2011, DMAS aims to reinvent its microwave absorber models.
Rik de Groot: “The main goal was altering its shape and enhancing the material composition for optimised RF performance above 20GHz. Since EPS is a closed-cell material, we encapsulate the high-loss dielectric material within our products, thereby solving the issue of dust particle leakage. The result is a stable RF performance that remains unchanged over time. Other notable USPs are the water-repellent nature of EPS and product rigidity to maintain their shape so that the tips will not sag.”
Our Senior Technical Consultant, Uliana Trucchi, further explains: “This is good for aesthetics because we like our rooms to maintain their appearance from day one, but it’s also excellent for consistent performance. The people at DMAS are so convinced of the quality of these absorbers that they come with a 25-year RF performance warranty. All our anechoic chambers for antenna testing come with these new microwave absorbers. However, if your current chamber has old, open-cell absorbers showing signs of degradation, please consult me for a rapid and safe solution for the next 25+ years.”