ECCOSORB VHY is a solid, pyramidal shaped, carbon-loaded hybrid absorber which has been designed for use in EMC test chambers. It consists of a thin lightweight matching layer and a pyramidal shaped resistive top part. It is meant to be used on top of ferrites and provides an adequate wideband performance for EMC test chamber applications in the frequency range from below 30 MHz to over 30 GHz when combined with the correct ferrite. Frequently it is the only possible absorber choice if there are severe space constraints. For large EMC facilities (TL = 10 meters and large EUT), ECCOSORB HX (see Technical Bulletin EB-125) is usually the most cost-efficient absorber solution.  For antenna or RCS test chambers, ECCOSORB VHP (see Technical Bulletin EB-100) are usually the preferred solutions because of better performance at microwave frequencies.  Whereas the ferrite part is non-combustible, the matching and pyramidal parts are fire-retardant according to the U.S. Naval Research Laboratory (NRL) 8093 Specification.

Application:

Typically ECCOSORB VHY-12 and VHY-18 are used in fully compliant 3 m chambers whereas ECCOSORB VHY-30 and VHY-40 are used in fully compliant 10 m chambers. However, the optimal lay-out depends on the precise chamber dimensions and test confi guration. It can only be determined by numerical simulation of the performance of the proposed anechoic chamber.