Investigation on additive manufacturing with conductive PLA filament for realisation of low-loss suspended microstrip microwave circuits

摘要

In this paper we investigate the applicability of additive manufacturing with conductive Polylactic Acid (PLA) based filament for realization of low-loss suspended microstrip microwave circuits. Filament is used to 3D print case which serve three major functions: provides mechanical enclosure and support for the circuit, provides appropriate elevation of the thin laminate with circuit mosaic over the ground plane and can potentially serve as the ground plane. The influence of the bulk conductivity of the utilized filament on total losses within the structure has been studied. Moreover, an exemplary transmission line hosted in Fused Deposition Modelling (FDM) 3D printed case has been manufactured and measured. Graphene-enhanced PLA material having volume conductivity of ≈ 166 S/m has been used yielding total loss of ≈ 0.14 dB/cm/GHz while reference case with copper foil ground plane yields total loss of ≈ 0.04 dB/cm/GHz.