ESorb Broadband Foam Absorbers

ESorb Broadband absorbers find their way typically in free space applications where the absorber material provides a high level of insertion loss and a high reduction of the applications reflectivity level. ESorb absorber materials are developed for a broad frequency range from UHF up to the EHF. Broadband absorbers are made from different base materials flexible and rigid polyurethane foam.

Typical broadband applications are metal structures and masts to reduce their reflectivity level, cross talk reduction between antenna systems, modification of RCS or improvement of stealth applications. Special solutions for customer specific requirements are also possible.

The most common broadband absorbers are presented below.


ESorb-MLA is a range of flat sheet, lightweight carbon loaded foam absorbers. The flat sheet absorber is a multilayer structure which consists of individually tuned absorbing layers each with their specific dielectric gradient to obtain its best possible matching with the impedance of air. The absorber sheets have a controlled dielectric loading which is impregnated with a binder system and fire retardant additives. This absorber material is available in 6 different thicknesses where each type is related to its operating frequency. Typical reflectivity level of the absorber is -17dB at normal incident energy.

ESorb-MLA is a typical broadband absorber which find its use in free space and cavity applications. For specific applications where the absorber is used in a harsh environment we can supply the absorber material equipped with protection like, vinyl, tissue or coating.


ESorb-OFA is a range of light weight open cell (reticulated) microwave foam absorbers. The single layer reticulated polyurethane foam material is coated with a dielectric carbon solution with fire retardant properties. Due to its open cell structure and a specific production process the absorber material obtains a dielectric conductive gradient to meet an excellent RF performance level. To meet customers mechanical and RF requirements different thicknesses are produced, typical thicknesses are 5, 10, 15 and 25mm. Typical frequency of operation is above 3 GHz, the thickest material is used in the low frequency range.

When a reflectivity performance is required the material can be supplied with an integrated metal backing. Similar as with our other polyurethane based absorber also ESorb-OFA can be supplied equipped with a protective tissue, typical a vinyl fabric is used.


ESorb-CFA is a range of high performance electrically taper shaped microwave absorber. The absorber is made from a light weight polyurethane foam material which is impregnated with a dielectric carbon and fire retardant solution. ESorb-CFA has its typical convoluted front face shape the material provides an ideal impedance taper which gives the absorber a superior RF performance at higher frequencies. Due to its specific shape the absorber material remains at his high performance level independent the angle of incident energy or the signal polarization.

Three different heights are produced : 3, 4 and 6 inch height. Typical frequency of operation is above 1 GHz.


ESorb-SLA  is a range of flat sheet flexible microwave absorbers produced from a polyurethane foam material by impregnation with a dielectric carbon loading. Different dielectric grades and thicknesses are available, the material is typically characterized by its level of insertion loss at a given frequency. By adjusting its thickness and losses one can tune insertion loss properties to optimize the required attenuation. Lossy foam sheet absorbers are a low cost solution to absorber unwanted RF signals above 1 GHz. The absorber is a carbon foam based material if needed the material can have an additional treatment by impregnation of a coating to avoid dust release.

Furthermore if needed we can supply the absorber material equipped with protection like, vinyl, tissue or coating. The absorber material can also be used for the isolation of antennas by insertion loss properties. ESorb-SLA is often supplied with a self-adhesive backing, the material can easily be cut with a knife.

An overview of our Broadband Foam Absorbers incl. data sheets can be found here.

We will be happy to help you with the selection or advise you which material makes the most sense in your case. Please feel free to contact our team directly here!