A Two-dimensional Multibeam Antenna Array Based on SIW Butler Matrices

In this paper, a wideband two-dimensional (2-D) 16×16 Butler matrix based multibeam antenna array in the range from 24GHz to 28GHz is presented for 5G millimeter wave (mmWave) applications. The 16 beams are controlled by two stages of substrate integrated waveguide (SIW) Butler matrices placed orthogonally. Each output port of the first-stage Butler matrices stacked vertically is twisted 90 degrees and connected to the corresponding input port of the second-stage Butler matrices stacked horizontally. The novel 2-D interconnection method is implemented based on the flexibility of the SIW without any connectors, cables and soldering operations, and then possesses the advantages of low cost, extensible and integrated easily in the mmWave bands.