Theory Analysis and Realization of Single-/Dual-Port Excitation in Beam-Forming Network

In this communication, rigorous analysis of dual-port excitation in beam-forming network (such as Butler matrix and Rotman lens) is presented. The strategies for selecting two input ports of beam-forming network in dual-port excitation and choosing the phase differences between two input ports are both given. A simple reconfigurable network is presented for realization of the single-/dual-port excitation, which can be easily extended for more input ports in beam-forming network. For verification, a 4 × 4 Butler matrix with the reconfigurable network and four-element array is designed and fabricated. The measured results show a good agreement with the theoretical analysis.