Synthesis and Design of Shunt Resonator-Based Phase Shifters With Reduced Phase Error and In-Band Magnitude Ripple

Hanjun Zhao, Hui Chu, Xiaohua Zhu, Yongxin Guo

Abstract: This paper presents a new design method for phase shifters that, for the first time, manipulates out-of-band transmission zeros (TZs) generated by shunt resonators to achieve the phase reconfiguration. Compared with conventional designs, the proposed out-of-band reconfiguration approach minimizes the impact on in-band performance during the reconfiguration, thereby substantially reducing in-band phase errors and magnitude ripples. With a derived closed-form phase slope formula, theoretical analysis is given to guide the unit design. Meanwhile, also based on this formula, the phase slope alignment is achieved for the entire phase shifter by utilizing the Particle Swarm Optimization (PSO) algorithm to optimize each individual resonator. To validate the proposed design method, two $C$ -band prototypes with different circuit topologies are designed, fabricated and measured. Both prototypes demonstrate a low phase error (±15.6° and ±5.0°) and magnitude ripple (0.7 dB and 0.6 dB), across a 360° phase tuning range, surpassing most existing phase shifters. This work is expected to be a good candidate for modern industrial applications including phased array radars, high precision phase modulators and other intelligent communication or sensing systems.