Experimental verification of multi-layer coconut shell-derived microwave absorbers

This paper presents experimental results of our study on multi-layer microwave absorbers synthesized using coconut shells as the source of activated carbon. In this investigation, activated carbon with content variation of 0, 10, 15, 20, 25 and 30 wt% were mixed with Flaxane-80 to study the microwave properties of the absorbers. Three- and four-layer microwave absorbers with various carbon contents were fabricated to study their reflection properties. A microwave non-destructive testing (MNDT) set-up was used to evaluate the microwave properties. Samples with 30 wt% carbon composite showed the highest relative permittivity of 17. All the four-layer absorbers fabricated in this work showed excellent performance in absorbing microwave signals, exhibiting respectable wideband performance with bandwidths up to 38%.