A novel additive-manufactured multiple-infill ultra-lightweight cavity-backed slot antenna for UWB applications

A rectangular ultra-wide band (UWB) cavity-backed slot antenna manufactured by combining 3D printing and ink-jet printing technology is introduced in this paper. The antenna substrate is made of polylactic acid (PLA) and is fabricated by using fusion deposition modeling (FDM). Two different infills are used for the slot area and for the area corresponding to the microstrip ground plane to reduce waste and dielectric loss. Thanks to 3D printing versatility, a cavity with slant sides, providing high gain, has been designed. This shape is aimed at increasing the antenna impedance bandwidth and directivity. The rectangular-like proximity-coupled feeding line of the antenna is fabricated by depositing silver nano-particle ink on a layer of SU8. The prototype has been tested and measurements confirmed the satisfactory antenna operation over the whole band of interest, from 3.1 to 10.6 GHz.