Novel staircase array antenna configuration using stacked Butler matrix for low profile base station

Massive MIMO is a promising wireless communication technology that realizes large capacity. However, it has the problem that circuit mounting becomes difficult due to the narrow antenna spacing and increased loss and phase deviation of connectors and wiring, especially in the millimeter-wave band. To solve these problems, we propose a novel Massive MIMO device configuration using a stacked Butler matrix and a staircase array antenna. From the simulation results, the radiation patterns are the same between the proposed and conventional antenna at stairs up to about 0.1 lambda.