3D Printed Wideband Microwave Absorbers using Composite Graphite/PLA Filament

Fused Deposition Modelling 3D printing of microwave absorbers using composite graphite / PLA (G/PLA) filament is explored. The permittivity and loss tangent of a slab of G/PLA is carefully measured for proper modelling. With a loss tangent of 1.6 and permittivity of 23 at 3 GHz, this lossy material is a promising candidate for low cost absorbers easily manufactured in arbitrary 3D shapes. Two wideband G/PLA absorber designs are presented. A truncated pyramidal absorber is manufactured and measured in a waveguide. Also a Frequency Selective Surface (FSS) designed for 6-8.5 GHz UWB radar is characterized in free space. Both designs have wideband absorbing properties and the measured results match full wave simulations. With these results we have shown that 3D printing with G/PLA is a promising technology for realization of fully functional microwave parts. 3D printing offers design flexibility giving fast, low-cost and simple production for light-weight parts appreciated in miniaturized and portable applications.