Abstract: A method for effectively decreasing electromagnetic radiation by means of active absorbing material in a broad frequency band, preferably from 100 MHz-10 GHz, is provided wherein the material combines the desired shielding properties with the heat insulating properties of a porous material in addition to providing a favourable ratio between density and resistance. The method includes use of an absorber granulate which consists of a highly porous glass and/or ceramic granulate which is coated or filled with ferrite and/or an electrically conductive material.