Experimental Verification of 3D Printed Low-Conductivity Graphene-Enhanced PLA Absorbers for Back Lobe Suppression in Aperture-Coupled Antennas

In this paper, the application of 3D printed, Iow-conductivity material absorbers is experimentally verified for back lobe suppression in aperture-coupled patch antennas. Various shapes and thicknesses of absorbers such as flat slab and array of pyramids were tested for maximum suppression of the aperture radiation. Moreover, different suspension height below the feeding network have been tested for the influence on the antenna's impedance match. A reference aperture-coupled broadband suspended patch antenna operating at center frequency of 5.6 GHz along with absorbers printed using Fused Deposition Modelling (FDM) type 3D printer out of graphene- enhanced Polyactic acid (PLA) filament were used for verification of the proposed technique. The obtained results show as much as 7 dB lower back lobe level compared to the case of a reference antenna.