Yu et al. Figure 3. System architecture of a phase shifting-based MBPAA. (a) Passive type. (b) Active type. DIGITAL BEAMFORMING DBF [1], [14], [15] is a spatial filtering method that uses an application-specific integrated circuit (ASIC) or a field-programmable gate array to perform weighted summation operations on baseband signals to form multiple beams, which is MARCH 2023 produced by the combination ofmodern digital signal processing technology and array antenna technology. These weights are known as beamforming coefficients. The most significant advantage of DBF is its ability to generate a large number ofbeams, which overcomes the limitation of the number of beams formed due to the package IEEE A&E SYSTEMS MAGAZINE 31