A Terahertz Wide-Angle Beam-Steering 3D-Printed Dual-Polarized GRIN Lens With Planar Focal Surface

A terahertz gradient-index (GRIN) dual-polarized lens with wide-angle beam-steering is designed in this article. A novel GRIN distribution is designed by superimposing the refractive index of the Luneburg lens and the Gutman lens to expand the beam-steering angle. The effects of the superposition ratio of Luneburg lens and Gutman lens <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\bm{\ }}$</tex-math></inline-formula> on the scanning performance of GRIN lens are studied. The novel GRIN distribution is provided for two different purposes. The lens has good scanning performance with a planar feed, and dual polarization can be achieved. High-precision 3-D printing technology is utilized to fabricate the proposed lens to verify the proposed GRIN distribution. A GRIN lens with an aperture size of 8 mm × 8 mm and a thickness of 6.4 mm was manufactured. The proposed lens is measured to validate the implementation method at 220 GHz. The results show that the proposed GRIN lens has a wide beam scanning angle of ±39° and ±38° in vertical polarization and horizontal polarization, respectively. The lens has a peak gain of 19.2 dBi. The scanning losses of the lens are 0.5 dB for vertical polarization and 0.7 for horizontal polarization, respectively.