A PCB‐stacked air‐filled Luneburg reflector lens antenna for 5G millimeter wave applications

Abstract

A wideband Luneburg reflector lens antenna with multi‐beam scanning performance is proposed for 5G millimeter wave (MM‐wave) applications. The proposed lens antenna consists of two groups of PCBs, four feed antennas, and a reflector. Holes are drilled with various radius in each layer of PCB (except the top and the bottom layers), so the air spacing between the two groups of PCBs changes discretely, which realizes the graded refractive index (GRIN) of the Luneburg lens. Owing to the utilization of the reflector, the size of the proposed lens is reduced by half compared to the conventional cylinder Luneburg lens, and the aperture efficiency is enhanced since the radiation aperture is reduced. The measured −10 dB impedance bandwidth covers 32–38 GHz with isolations better than 19 dB. The radiation beams demonstrate an azimuthal scanning range of 20–66 deg. It is a good candidate for 5G MM‐wave applications.