Dual-Beam Multiplexing Under an Equal Magnitude Constraint Based on a Hybrid Beamforming Structure

By adjusting the adjacent antenna spacing in terms of the relationship between the two required directions, previous techniques can multiplex two beams by changing the phase of different antennas. In this work, to maintain the adjacent antenna spacing as a fixed value and reduce the implementation complexity, one novel design with an equal magnitude constraint for all antennas, together with the inter-subarray coding scheme is proposed, which can achieve dual-beam multiplexing for arbitrary directions to serve two users via merely changing the analogue phase shift of each antenna. Following a most recent development in this area, the idea can be easily extended to multiple beams. Designed examples are provided to demonstrate the effectiveness of the proposed method.