Wideband Beam Squint Analysis for Antenna Array-Equipped Satellite Communication Systems

Wideband (WB) satellite communication (SatCom) systems, which utilize millimeter-wave (mmWave), sub-THz, and THz frequencies, are expected to be key enablers for 6G technology. However, employing beamforming transmission with an antenna array over these high-frequency WB is facing a significant challenge relating to the beam squint (BSq) effect. This phenomenon causes frequency-dependent variations in antenna radiation patterns, leading to misalignment of beam steering and degraded signal strength at off-center frequencies. This paper provides an in-depth analysis of the BSq effect and its impact on antenna gain across frequency and spatial domains in WB SatCom systems. Various compensation techniques are studied to mitigate BSq, including delay-based methods, hybrid beamforming (BF), and codebook-based BF, and antenna spacing-based design. Our findings demonstrate that the delay-based methods and hybrid BF are the most effective solutions for mitigating BSq when sufficient hardware resources are available. Additionally, the proposed low-complexity codebook-based BF and antenna spacing-based design demonstrate their effectiveness in enhancing BF gain and reducing the BSq effect, which are critical for the future of WB communication systems.