Multibeam Characteristics of an Array Antenna for 5G Mobile Base Station

Abstract

The fifth-generation (5G) mobile communication system requires the multibeam base station antennas to cater to the increasing demand for higher data rates. To clarify the realization of a multibeam array antenna in the millimeter wave band, a feeding network of a Butler matrix circuit was designed at 28 GHz. In this paper, multibeam radiation characteristics using an 8 × 8 Butler matrix with antenna spacing of 0.6λ to 0.8λ are studied to control the multibeam coverage area. The simulated results of main beam direction agree very well with the calculated results of main beam direction. The appearances of grating lobe are observed when the antenna spacing is more than 0.7λ. The gain reductions and radiation pattern deformations are observed.