## 1 Introduction
(6) Application Scenarios:  
ABF: ABF is suitable for applications where beam precision is not a major concern, and the system is relatively simple, such as in traditional radar systems, communication systems, etc. DBF: DBF is widely used in modern radar systems, satellite communications, wireless communications, interference suppression, and other fields. It is especially advantageous in LEO satellite systems and high-precision radar systems, where DBF offers greater flexibility and superior performance. Conclusion:  
In summary, the greatest advantage of DBF over ABF lies in its higher flexibility, more precise beam control, and stronger adaptive capabilities. However, it also requires more complex hardware and higher costs. In applications that require high performance and complex beam control, DBF is often the superior choice [4]. Considering the above factors, DBF was chosen for beamforming in this design. In the above process illustrated in Figure 1, digital beamforming (DBF) uses digital phase shifting to compensate for signal delays caused by the physical characteristics of signal transmission in each channel, including delays caused by direction-of-arrival (DOA) or angle-of-arrival (AOA). This ensures phase alignment for incoming signals from a specific direction, achieving coherent superposition and maximizing energy reception in the desired direction [5]. By adjusting beamforming weights, the beam can be steered in different directions to achieve beam scanning. Through parallel multi-channel processing, multiple beams can be formed simultaneously in various directions [6]. In addition, selecting an appropriate window function can reduce the intensity of side lobes. Beamforming corrects the phase of signals to ensure phase consistency across multiple channels, allowing the direct accumulation of multi-channel data to enhance signal power. Antennas employing DBF exhibit excellent self-calibration and low sidelobe performance. These advantages of DBF, which are absent in ABF, have a profound impact on improving receiver performance [7]. Despite its unique capabilities and advantages, DBF technology has garnered significant attention in radar applications but is constrained by beamforming accuracy and gain. As DBF technology continues to evolve, improving its accuracy and gain has become a focal point of research and development worldwide. Below is an overview of the current research status of DBF both internationally and within China. Globally, DBF has been extensively studied and applied across various domains:  
(1) In radar systems, NASA's Goddard Space Flight Center has been at the forefront of developing advanced DBF synthetic aperture radar (SAR) systems in 2016. These systems employ multiple-input and multiple-output (MIMO) architectures characterized by multi-mode operation, software-defined waveform generation, DBF, and configurable polarimetry, enhancing radar performance and opening new capabilities in radar remote sensing [8]. (2) In terms of space applications, [PERSON] and [PERSON] from the National Commission on Space Activities (CONAE) in Argentina have been developing a DBF radar system for technological research, highlighting the global interest in DBF for space applications, most recently in 2024 [9]. (3) In algorithm development, researchers have explored the evolution of beamforming over the past twenty-five years, transitioning from convex to nonconvex optimization and from optimization to learning approaches. This progression has led to significant advancements in signal processing algorithms for various transmit/receive architectures and multidisciplinary applications [10]. In China, DBF research has also made significant strides:  
(1) In adaptive beamforming, [PERSON], [PERSON] et al. have focused on adaptive DBF technologies, proposing system architectures based on super-resolution spatial spectrum estimation to improve performance under non-ideal conditions, as detailed in their study from 2021 [11]. (2) In hybrid beamforming, [PERSON], [PERSON], et al.