A 2.2–3 GHz Non-Quadrature Vector-Sum Phase Shifter With Low-Phase Error and Based on Coarse-Fine Tuning

Abstract

This letter presents the design and implementation of a novel analog phase shifter architecture based on generating and synthesizing non-quadrature vector signals. The phase shift is achieved through coarse and fine-tuning. The coarse tuning is executed by the path selectors of the generated phase vectors, whereas tunable passive attenuators do the fine-tuning. The proposed phase shifter was implemented on a commercial PCB and tested at 2.6 GHz center frequency. The fabricated protocol generates a 360° continuous phase shift from 2.2 to 3 GHz with an RMS gain imbalance of 1.1 dB at the center frequency. Moreover, the measured RMS phase error is 0.115° at the center frequency and less than 2° within the bandwidth, which is ultra-low for an RF phase shifter. With a size of 1.2 ${\lambda }_g$ × 0.8 ${\lambda }_g$, the fabricated phase shifter consumes a small DC power of about 6.2 mW, which is smaller than the power consumed by most vector modulators.