A Wideband 1×3 Filtering Beamforming Network Featuring Input-Reflectionless and Extended Phase Reconfigurability

In the paper, a wideband 1×3 filtering beamforming network (BFN) with extended phase reconfigurability and input-reflectionless feature is presented for the first time by employing three-way reflectionless power divider, switched 0°/180° phase shifter (PS), and multiway polyphase filtering differential phase shifter (D-PS). The three-way power divider and D-PS provide wideband filtering with high frequency selectivity while ensuring an input-reflectionless characteristic across the entire frequency range. Six distinct output phase differences (PDs) can be realized using only three groups of D-PSs in combination with the switched 0°/180° PSs, enabling extended beam directions without additional phase-shifting components added. The designs of the three-way power divider and D-PS are presented, with the D-PS accompanied by derivation of equations and parametric analysis for clarification. To verify, a prototype is fabricated and measured. Measurements verify six differential PDs of –120°, –90°, –30°, 60°, 90°, and 150°. For all six states, the prototype achieves a 3-dB passband bandwidth exceeding 70% with |S11| below -10dB across the entire frequency range. In addition, the fractional bandwidth corresponding to a ±7° PD error reaches 40%. Keywords: Beamforming network, filtering, input reflectionless, phase reconfigurability, multiway polyphase phase shifter