An antenna for switch beam, multi-beam millimetre-wave cellular systems

Abstract

This paper presents the design and implementation of a compact, two-dimensional antenna with broadband performance capable of increasing system capacity for next generation 5G base stations. This simple low profile, parallel plate Luneburg lens can be exploited to ensure high energy efficiency, higher data rates, spectral efficiency, and extended coverage leading to a reduction in the number of physical base station antennas, and towers. Inserted between the parallel plates are two identical machined dielectric lens profiles each with a smooth dielectric permittivity gradient, varying from 2 at the center to 1 at the edge corresponding to Luneburg lens design specification. The lens is fed by ultra-low loss open-ended waveguides with probe launchers to inject multiple independent beams at the lens surface and between the plates. The broadband lens has a 3-dB beamwidth of 40° × 5.3° in the E and H plane and an average radiation efficiency greater than 70%. Cross-polarization and port isolation is greater than 30 dB, allowing for the effective co-existence of multiple input beams. The switch beam antenna implementation was optimized to operate in the Ku-band but can be scaled to any suitable mm-wave frequency.