2D flat Luneburg lens antenna for multibeam scanning application

Abstract

A two-dimensional (2D) flat Luneburg lens antenna (LLA) operating at Ka-band is presented in this Letter. Based on the transformation optics, the 2D conventional Luneburg lens is compressed to the flat form. The proposed flat LLA is composed of six discretised dielectric layers with different permittivity, two metallic parallel plates and an E-shaped microstrip patch antenna array. By switching on/off the array elements, the lens antenna is able to achieve 1D beam-scanning with a scan coverage of ±30° at 28 GHz. The proposed lens antenna has a low profile of 7 mm, a focus-to-diameter ratio of 0.42, and the simulated/measured aperture efficiency for the on-axis beam is 56.8/36% at 28 GHz. The proposed 2D flat LLA is highly suitable for 5G mm-wave wireless communication with the advantages of low profile, wide beam-scanning range, low cost, and easy fabrication.