A 9-Bit Vector-Sum Digital Phase Shifter Using High Resolution VGAs and Compensated Quadrature Signal Generator

摘要

In this paper, a 90–98 GHz vector-sum digital phase shifter with high phase accuracy and low power consumption is presented for W-band phased-arrays. The proposedphase shifter is based on a quadrature all-pass filter (QAF) and four identical variable gain amplifiers (VGAs) with 7-bit current-digital to analog converters (I-DACs). To eliminate the parasitic loading capacitance influence of the VGAs on the QAF, a inductor-based compensation network is utilized. Then, specific phase shifting could be obtained. Meanwhile, the digital pre-distortion (DPD) technology is used to further improve the phase error performance. To verify the mechanisms mentioned above, a W-band digital phase shifter is implemented and fabricated in a 40-nm CMOS technology with a core size of 0.058 mm². The measured results after DPD exhibit the root mean square (RMS) amplitude error of 0.67-1.23 dB and RMS phase error of 0.60°-0.71° from 90 to 98 GHz. Additionally, the phase shifter features an average gain of -1.29 dB at 92.1 GHz with a power consumption of 14 mW from 1.1 V supply.