Anechoic chambers are rooms designed to absorb reflections from sound and electromagnetic waves. This is made possible through the rooms' use of specialized absorbent lining. This lining allows wave sources placed inside the chamber to be isolated from external wave sources and interference. Compact anechoic chamber systems are modern, portable, and flexible alternatives to full-scale anechoic rooms. These versatile chambers are used for many purposes and in many industries, including consumer electronics, scientific, medical, automotive, aerospace, telecommunications, and more.
There are two primary types of anechoic chamber systems: acoustic anechoic chambers and radio-frequency chambers. Each type is designed to absorb the corresponding type of wave through differing applications of advanced technologies. If you're considering using anechoic chambers in your own projects, read on below to find out more about the 2 most common types of compact anechoic chamber systems.
Compact Acoustic Anechoic Chambers
Compact acoustic anechoic chambers are used to create free field conditions. Free field means that an environment is echoless and completely isolates the initial sound source. This environment is ideal for experiments and research that require extremely precise acoustic measurements. The inside of compact acoustic anechoic chamber systems can be as quiet as -20 decibels. For an ordinary human, this is effectively a completely silent environment. Anything below 0 decibels is inaudible.
To produce this effect, walls are lined with wedges made of acoustically absorbent materials like fiberglass. Sound waves are bounced back and forth between the wedges while simultaneously being absorbed due to the acoustically absorbent wedge material. After enough bounces, the acoustic energy is neutralized, eliminating any audible trace of the sound.
Compact Radio-Frequency (EMC/EMI) Chambers
Compact radio-frequency chambers, also known as electromagnetic compatibility (EMC) or electromagnetic interference (EMI) chambers, are used to isolate radio waves for precise measurement. The inside of compact radio-frequency chambers can measure frequencies as low as 10 kilohertz but typically only offer absorption for frequencies as low as 30 megahertz. The complete isolation of the chamber allows researchers and quality assurance teams to perform detailed testing, measurement, and analysis. To produce this effect, instead of being lined with wedges, radio-frequency chambers are lined with pyramids. These pyramids are typically made of radiation absorbent materials like ferrite tile and carbonized polyurethane foam. Ferrite tile has poor absorption at frequencies below 1.5 gigahertz, while carbonized polyurethane foam is best for lower frequencies. However, polyurethane foam pyramids must be made significantly larger to produce the desired level of absorption. For example, a carbonized polyurethane foam pyramid must be 2.4 meters long to absorb frequencies as low as 30 megahertz.
Conclusion
As you can see, compact anechoic chambers are an essential tool for precise sound and radio-frequency measurement. Now you know how anechoic chamber systems can be beneficial for your next project.