3D-Printed Graded Index Lenses for RF Applications

Authors: Shiyu Zhang, Yiannis Vardaxoglou, Will Whittow, Raj Mittra

Source: FERMAT, Volume 28, Communication 6, Jul.-Aug., 2018

Abstract: A lens is a well‐known antenna component that converts the spherical wavefronts emanating from a feed into planar wavefronts; and therefore, it can be used for antenna application to realise a high directive beam. This work introduces two flat graded‐index (GRIN) lens designs. First of these is a thick lens which was designed and fabricated by using the 3D‐printing technique. Second, a thin Dial‐a‐Dielectric (DaD) lens which uses state‐of‐the‐art artificially engineered dielectric materials for design and will be fabricated in future. Both designs overcome the difficulties faced in finding desired commercial off‐the‐shelf (COTS) materials for 3D‐printing lenses. The lenses comprise of several concentric dielectric rings with bespoke relative permittivities for transforming spherical waves into plane waves and vice versa. The 3D‐printed thick flat lens is low‐cost and light‐weight, but provides broadband and high gain performance. Measurement results show that the realized gain of the thick lens is 16‐24 dBi over the frequency band of 12‐18 GHz. The designed DaD lens has the desirable characteristics of low loss, low reflection and broadband properties.

Index Terms: 3D printed lenses, artificial dielectrics, additive manufacturing, lens antennas, graded‐index lens designs, Dial‐a‐Dielectric Lens

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3D-Printed Graded Index Lenses for RF Applications