Investigations on the Efficiency of Array Fed Coherently Radiating Periodic Structure Beam Forming Networks

The concept of coherently radiating periodic structure beam forming network (C-BFN) has been introduced recently in the literature as a possible mean to feed linear or planar arrays. Losses are expected in such a structure as it produces non-orthogonal excitation laws, motivating the investigations on C-BFN efficiency presented in this paper to guide antenna designers. Mono- and multi-beam applications are considered, including also beam steering capability. These investigations help define some useful design rules depending on the application. Some evolutions are also proposed that may overcome some limitations of the original concept. All the presented results are supported by both simulations and measurements of various prototypes designed on printed technology at 6 GHz.