Multimaterial 3-D Printed Compressed Luneburg Lens for mm-Wave Beam Steering

Conformal, steerable lens antennas are of particular interest for millimeter-wave (mm-wave) antenna designers, as they enable low cost solutions for applications such as 5G mobile communications, radio-wave imaging, and satellite communications. Recent advances in additive manufacturing technology have opened up new possibilities for realizing graded-dielectric electromagnetic devices. In this letter, a compressed Luneburg lens fabricated from multimaterial 3-D printing is presented. Such a device has a steep dielectric gradient and cannot be easily realized using an effective medium approach that has become typical of 3-D printed graded-index devices. Instead, five different dielectric filaments were used to print the lens with a 100% filament fill-factor. The lens is excited by a WR-10 open-ended waveguide probe across the 75–110 GHz band, and achieves a bore sight gain of 22 dBi, and
$-$
3 dBi scan angle of 25
$^\circ$
at 84 GHz.