Compact Filtering Phase Shifter With High-Frequency Selectivity and Wide Stopband

In this research paper, a compact filtering phase shifter (FPS) featuring high-frequency selectivity and a wide stopband is introduced. Through the utilization of the proposed dual-mode ring resonator (DMRR) structure in both the reference and main branch, a filtering passband with high-frequency selectivity and a wide stopband can be achieved. Simultaneously, by delicately incorporating the delay line and bandwidth in the main branch, a constant phase difference within the passband is acquired. For verification, a prototype of the FPS is designed, fabricated, and measured using printed circuit board (PCB) technology. The measured results are found to be in good agreement with the simulated ones.