Enhancement of complex permittivity and attenuation properties of activated carbon derived from oil palm fruit fiber for microwave application

Abstract

This study aimed to synthesize activated carbon (AC) from empty oil palm fruit bunch (OPEFB) fiber to enhance its complex permittivity properties by modifying the particle size and surface area via physical activation. Sample characterizations of complex permittivity were conducted using open-ended coaxial technique and a vector network analyzer. The absorption properties were analyzed using the finite element method (FEM) simulations of the transmission coefficients and the distribution of electric fields via the microstrip models. Simulations and measurements were all carried out within the range 8–12 GHz. The initial surface area of the unactivated sample was 4.02, after 700, 750, and 800 °C activation, 730.40, 814.00, and 927.01 m2/g was obtained respectively. With increased surface area, the dielectric constant and loss factor values increased and attained maximum values of 6.13 and 0.83 at 8 GHz, respectively from initial values of 3.63 and 0.52, as the surface area increased from 4.02 to 927.01 m2/g. The improved absorption properties displayed by the AC in the simulations demonstrated their capacity to attenuate X-band microwaves.