Microwave absorber materials characterization: bulk absorbing and electrical/magnetic parameters

Microwave absorber materials are used extensively in anechoic chambers for antenna measurement, to emulate free-space conditions. They are also used to suppress unintended radiations in consumer electronic products (so that they present conformity to existing regulations) and other applications. Their characterization usually shows the amount of damping in a certain frequency range, and it depends on the materials used in the mixture and its overall geometry. This article deals with Brazilian and international manufactured, low cost absorbing materials, characterized in both bulk format (damping) as well as its material parameters (electrical permittivity and magnetic permeability).