A $64\mathrm{x}64$-way Two-dimensional Beam-switching Butler Matrix for Multi-beam Massive MIMO

Abstract

This paper presents a $64\mathrm{x}64$-way one-body two-dimensional beam-switching Butler matrix for multi-beam massive MIMO transmission that eliminates channel state information estimation with constant modules algorithm in the digital part. The one-body two-dimensional switching matrix is realized by introducing the waveguide 2-plane couplers as hybrid and cross junctions. The 64 beams can cover 39.5% hemisphere by 0.65-wavelength aperture spacing in simulation. The measured beam coverage is almost the same to the simulated one. The effectiveness of the multi-beam massive MIMO using measured 8 by 8 beam patterns with the planar array is also clarified.