Abstract

The electromagnetic wave absorption characteristics of composite cement-based building material have attracted much interest in recent times. Researchers have mainly focused on the 2 GHz to 12 GHz frequency range while the authors have investigated the mobile and WiFi frequency bands. The determination of characteristics such as reflection loss, absorption, attenuation and shielding effectiveness are crucial in the evaluation and development of these materials for the building industry. The authors have determined the characteristics by measuring the S₁₁ and S₂₁ parameters of the composite cement-based material in the Global System for Mobile (GSM) and WiFi frequency bands. MnZn-ferrite and electrolytic manganese dioxide in powder form is used as absorber material to increase the permeability of the cement-based material to improve absorption and attenuation capabilities to create a cost-effective practical electromagnetic wave absorber. The results achieved show the uniqueness of electrolytic manganese dioxide as filler in composite cement based material for electromagnetic wave shielding effectiveness improvement. Shielding of 8 dB in the GSM850 and GSM900 frequency bands and 5 dB in the GSM1800 and GSM1900 frequency bands were measured.

Key words: Electromagnetic wave absorption measurement, attenuation, magnetic composites in building material, reflection loss, shielding effectiveness, transmission loss