Wideband Dynamic Array-of-Subarrays Architecture for Extremely Large-Scale Antenna Array Systems

Recently, wideband beamforming using extremely large-scale antenna array (ELAA) systems have gained much interest as a means to boost throughput in next generation (xG) networks. However, conventional phase shifter (PS)-based beamforming methods face challenges in wideband ELAA systems due to the beam squint effect, where beams at different frequencies become misaligned. Although the use of true time delay (TTD) can address this by creating frequency-dependent beamforming vectors, traditional TTD-based methods still experience considerable sidelobe leakage due to the mismatch between intended and generated beams. In this paper, we introduce a novel wideband beamforming architecture that dynamically configures connections between TTDs and PS subarrays using a switching network. By jointly optimizing subarray connections, TTD time delays, and PS phase shifts, wideband dynamic array-of-subarrays (WDAoSA) minimizes sidelobe gain and maximizes array gain in wideband ELAA systems. Numerical results show significant improvements in both array gain and data rate compared to conventional TTD-based methods.