Beam Distortion in Generalized Joined Coupler Matrices: Analysis and Resolution

The Generalized Joined Coupler (GJC) matrix that can generate independently scannable multibeams emerges as a promising candidate for the next-generation wireless communications.However, when beams overlap, severe beam distortion occurs, significantly degrading system performance and limiting practical deployment.This paper examines the root cause of this critical issue and proposes to use reconfigurable directions couplers to address it.Two methods, including the scanning multibeam optimization (SMO) and its enhanced version, improved SMO (ISMO), are developed.The SMO method optimizes couplers to effectively suppress beam distortion in Blass-like GJC.To deal with Nolen-like GJC matrices, ISMO introduces an iterative coupler and phase optimization (ICPO) strategy for enhanced and efficient optimization.Numerical results demonstrate that SMO and ISMO effectively correct mainlobe distortion, ensuring continuous multibeam scanning.These improvements greatly enhance the capabilities of GJC matrices, paving the way for advancements of analogue multibeams in the 5G and beyond communications.