ABSTRACT
Multibeam systems have been used in many applications, such as communication systems, multiple target radars, etc. In the millimeter-wave frequency band, the power budget is usually costly and difficult to meet the requirement for long-distance applications. Therefore, high-gain, high-efficiency, and potentially multibeam schemes are necessary for millimeter-wave systems. In view of the rapid development of multi beam antenna systems, the beamforming network (BFN) has become a hotspot of research in recent years [187-189].
