Development of Metamaterial Using Waste Materials for Microwave Absorption

The present study focuses on the use of waste materials to generate cost-effective microwave absorption composites. Rice husk (agricultural waste) and exhausted activated charcoal (water filter cartridge waste) were used as waste materials for microwave absorption. Both were blended in different proportions using a planetary ball mill to prepare samples. The XRF and particle size studies were carried out for element and particle size analysis, and for dielectric properties measurement, a vector network analyzer was used. The findings reveal the microwave absorption in the frequency range of 2 to 18 GHz by the blended composites. Sample RHC-11 with 20% exhausted activated charcoal showed a maximum reflection loss of − 38.3 dB at 12 GHz. For further improvement in microwave absorption, the dielectric characteristics of the composites were utilized to develop a layered metamaterial-based microwave absorber. The layered metamaterial is a unique and simple patch design that displays good microwave absorption > 90% and absorbs 99.34% of microwave energy at 16 GHz frequency. The developed metamaterial-based microwave absorber shows an absorption bandwidth of 6.60 GHz with a thickness of 2.3 mm. In addition, the proposed structure is independent of the oblique incidence angle and polarization angle.