Design of a High-Gain Patch Antenna Integrated with a 3D Printed Inverted Pyramidal GRIN Lens for mmWave Communications

Abstract

This paper presents the design and fabrication of an inverted pyramidal graded index (GRIN) lens made from polylactic acid (PLA) material using three-dimensional (3D) printing technology that was integrated with an mmWave-band planar patch antenna. To design a lens structure suitable for the characteristics of the 3D printing process, the lens was divided into 3D cubic voxels. Each voxel utilized the volume ratio of PLA to air to achieve the required effective permittivity, and the lens was designed using refractive index changes according to the effective permittivity. The designed lens had an inverted pyramidal structure and consisted of five vertical layers. The low-cost inverted pyramidal GRIN lens increased the gain of the planar patch antenna operating in the 24∼25 GHz band by 3.8 dBi.