ECCOSORB^® SFU is a series of thin Refers to the medium of air (or vacuum) in which radio waves may travel. This is in contrast to waves traveling on transmission lines such as coax or waveguide, or through a medium, such as an Free Space Absorber (Specular Absorber)free space resonant absorbers.  These magnetically loaded narrowbanded absorbers reflect 1% or less of normally incident energy (at least 20 The portion of incident energy which is reflected from a surface. A flat metal surface reflects all incident radiation. Measured in dB which is a logarithmic measure of the portion of energy reflected as compared to that reflected from a flat metal plate of the same area. A metal plate has a reflectivity of 0 dB down. A material which reflects half of the incident energy is 3 dB down or has a reflectivity of -3 dB. A material which reflects one tenth of the incident energy has a reflectivity of -10 dB Reflectivity (%) dB down. For flat sheet absorbers, 20 dB down is generally the best possible and desired performance.dB down) at design frequencies when intimately backed to a metal surface.

ECCOSORB^® SFU has increased abrasion and fuel resistance than its silicone counterpart, ECCOSORB^® SF with only a slight loss of flexibility.  In order to function properly, ECCOSORB^® SFU should be attached to a metal surface.  If required an integral reflective backing (ML) can be provided as well as a Pressure Sensitive Adhesive (PSA) for easy attachment.

Applications include lining radar nacelles (particularly where high power is present), lining of cavity backed and shrouded telecommunication antennas, lining metal surfaces to attenuate surface currents, and for lining magnetron housings to prevent detuning.