Dielectric split-pin unit cell for gradient index lenses implementation by using 3D-printing

This article presents the design and implementation of a dielectric split-pin unit cell for designing graded index (GRIN) lenses using 3D printing technology. The proposed unit cell aims to simplify the fabrication process of GRIN lenses by leveraging the advantages of 3D printing. The design consists of two metallic parallel plates, one with a high-permittivity substrate layer and the other with an array of easily printable dielectric pins of lower permittivity. The variation in the height of these pins allows for the creation of the desired refractive index profiles. Four types of GRIN lenses-Maxwell, Luneburg, Gutman, and Fission lenses-are analyzed and designed to operate at a central frequency of 20 GHz. The study includes a parametric analysis to determine the necessary dimensions of the unit cells to achieve the required refractive indices. The effectiveness of the proposed design is validated through full-wave simulations and measurements of one fabricated lens, demonstrating good agreement with theoretical predictions and confirming the viability of this approach for practical applications in high-frequency devices.