Design of 28 GHz Switched Beemforming Antenna System Based on 4×4 Butler Matrix for 5G Applications

In this paper, a switched beamforming antenna system operating at 28 GHz frequency band is designed for the 5th generation wireless communications applications. The Butler matrix is used as a beamforming system and it produces linear spaced phase difference at its four output ports. The array antenna is designed in order to be steered into four different desired directions at 28 GHz frequency band. The design details of the Butler matrix, mainly its couplers, phase shifters and crossovers, are provided. The antenna system is based on Rogers RT5880 substrate, (εr=2.2, h=0.25mm, tanδ = 0.001). The proposed design offers good performances and the obtained results are very promising.