A Low-Complexity Beamforming Network with Simplified Coupler Configuration for Precise Beam Steering and Sidelobe Control

This paper presents a novel beamforming network (BFN) design that utilizes a single type of coupler to achieve precise beamforming performance. The proposed BFN is constructed using a unique coupler topology based on Substrate Integrated Suspended Line (SISL) technology, which enables direct integration with the antenna array while minimizing losses and phase errors. By employing optimization algorithms such as Particle Swarm Optimization (PSO), the parameters of the couplers and phase shifters are determined, ensuring accurate amplitude and phase excitation across the array. The beamforming performance is validated through a 12GHz 3×8 BFN feeding a 1×8 dipole antenna array, which generates well-defined beam patterns steered at -30°, 0°, and 30°. The results demonstrate that the simplified coupler configuration achieves excellent beamforming capabilities, including high gain, low sidelobes, and accurate beam steering, while significantly reducing design complexity. This work highlights the potential of the proposed BFN for applications in advanced wireless communication systems, such as 5G and beyond.