Re-inventing the microwave absorber models!

Polyurethane absorbers have been the standard material for anechoic chambers for decades. However, while the open-cell foam structure ages, leakage of unwanted black dust is inevitable.
 
Most RF/MW engineers, often working in anechoic chambers, have experienced a layer of fine black dirt inside their chamber and on their clothes and hands. Some engineers have even mentioned keeping an extra set of work clothes for working inside the anechoic chamber because of this issue.
 
So, how did this happen, and how did they solve it? Rik de Groot, the owner of 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 destabilize the absorbers’ RF performance.”
 
After successfully introducing the hybrid EMC absorber in 2011, DMAS aims to re-invent its microwave absorber models. Rik de Groot: “The main goal was altering its shape and enhancing the material composition for optimized RF performance above 20GHz. Since EPS is a closed-cell material, we encapsulate the high-loss dielectric material inside our products, solving the issue of leakage of dust particles. The result is a stable RF performance without degradation 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, 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.”