A 3D-Printed Multi-Material GRIN Lens with an Integrated Matching Layer at 20 GHz

The design, fabrication, and experimental validation of a gradient-index (GRIN) lens operating at 20 GHz is presented. Different realizations with and without matching layers at the input and output interfaces are compared. The lens design employs a semi-analytical approach to compute the desired permittivity distribution, which is realized using a periodic dielectric structure with a spatially modulated volumetric infill. The lens is manufactured via a multi-tool 3D printer utilizing two different dielectric materials for the core and matching layers, respectively. The lens design with and without the matching layer is experimentally verified. The comparison highlights the critical role of impedance matching at the interfaces, with the lens exhibiting superior performance when matching layers are incorporated. This work demonstrates the potential of multi-dielectric 3D printing for producing mmWave components, suggesting its applicability in future high-performance antenna systems.