Synthesis and On-chip Design of Three-Port Phase Reconfigurable Filtering Network Based on Modified Coupling Matrix

This letter has proposed a synthesis method of three-port phase reconfigurable filtering network by modifying the coupling matrix. Through utilizing a cascaded triplet (CT) structure topology, a bandpass filtering response with an out-of-band transmission zero is achieved, enhancing frequency selectivity. The coupling relationships between components in the coupling matrix are leveraged to realize the reconfigurable phase-shifting function of the circuit. In pursuit of device integration and miniaturization, Integrated Passive Device (IPD) based on GaAs substrate technology is utilized. For validation purposes, the hybrid coupling topology is adopted and an on-chip balun filter with a center frequency of 9.68 GHz is designed. The experimental results demonstrate good agreement with the simulation outcomes, confirming the effectiveness of the proposed design method.