The solid, geometrically tapered microwave absorbers are preferred due to their better performance. The goal of this study is to design absorbers that can reduce the electromagnetic reflections to less than −10 dB. Two waste materials of sugarcane bagasse and rubber tire dust in the powder form were used to fabricate independent samples in the pyramidal form. This paper presents the complex permittivity measurements of sugarcane bagasse and rubber tire dust materials. These two materials are found to be potential absorbing materials in microwave frequency to allow absorption of microwave EMI energy. The materials were combined and fabricated in the composite structure. A measurement system using open- ended coaxial probe method was used for characterizing the dielectric properties of the materials in the range of 1 to 18 GHz microwave frequencies. The dielectric property was used to compare the propagation constants of the material. Comparison of the results proved that these two materials have industrial potential to be fabricated as solid absorbers.
