This paper presents the new design of simple one layer ultrathin metamaterial microwave absorber using coconut coir fibre as the substrate. The metamaterial microwave absorber is composed of a periodic array of square loops and patches with circle cut out printed on a dielectric material which is coconut coir fibre backed by PEC. CST Microwave Studio software is used for the design and simulation over frequency range of X-Band and Ku-Band (8.2-18 GHz). From the simulation result, 90% absorption was achieved in the frequency range of 8.94 - 10.0 GHz (X-Band) with highest absorption of 99.7% at 9.37 GHz. Furthermore, the metamaterial microwave absorber has a total thickness of 1.6 mm which is only approximately 0.04λ at lowest frequency. The result shows that coconut coir fibre from the agricultural waste has a great potential to be developed further in electromagnetic wave applications particularly microwave absorber.
