A planar wideband 2-D beam-forming network for multibeam application

This article presents a wideband 2-D beam-forming network (BFN) utilizing a three-layer strip-line structure, which has 16 input ports and 16 output ports. The BFN, composed of multiple 2-D couplers, crossovers, and phase shifter groups, can provide an equal power signal distribution with +/- 45 degrees or +/- 135 degrees phase differences between the adjacent output ports, hence achieving 2-D beam scanning in both azimuth and elevation planes. To validate the concept, a prototype operating in the frequency range of 2.25-3.75 GHz is fabricated, measured, and discussed. The measurement results coincide well with the simulation ones.