Three-dimensional (3D) Printed Dielectric Lens and Support Structure Mounted on an Open-Ended W-Band Waveguide

Abstract

A dielectric lens and support structure is designed and fabricated using three-dimensional printing. The lens is mounted onto an open-ended WR-10 waveguide and directly radiates into free space. The lens body has a relative permittivity that is lower than the polylactic acid (PLA) used to print the lens by lowering the infill fraction of the lens in the printer slicing software (PrusaSlicer version 2.5.0). A printed dielectric feed wedge is used to improve the radiating structure's return loss, resulting in an input reflection better than À10 dB across the entirety of WR-10 band from 75 GHz to 110 GHz. The lens exhibits a measured peak gain of 19.5 dBi at 100 GHz, with a maximum gain variation of 1.3 dB from 75 GHz to 110 GHz and uniform radiation characteristics in both the Ẽ plane and H plane. The lens provides a reduction in Ẽ-plane sidelobe levels (SLLs) compared with a standard gain WR-10 horn by approximately 10 dB across the band. Further reduction in the SLLs below 100 GHz is achieved by painting the base of the lens with a conductive RF shielding paint.