A 28GHz Area-Efficient CMOS Vector-Summing Phase Shifter Utilizing Phase-Inverting Type-I Poly-Phase Filter for 5G New Radio

Abstract

A 28GHz CMOS passive vector-summing phase shifter is demonstrated in this paper. The proposed design consists of a phase-inverting type-I poly-phase filter and a 45° switch-type phase shifter. By adopting the phase-inverting poly-phase filter for I/Q generation, I/Q weight assignment and summation, the proposed design can realize ± 22.5° phase tuning with fine resolution in each phase quadrant. Together with the 45° phase shifting provided by the switch-type phase shifter, the proposed design can achieve a 360° phase coverage in a compact area of 0.1mm2. Transformers are utilized for the inter-stage and output matching, which shrink the area compared with transmission lines. In measurement, the fabricated passive vector-summing phase shifter realizes a root mean square (RMS) phase error smaller than 1.77° from 26.5GHz to 29.5GHz and reaches 0.06° at 28GHz with the help of the fine-tuning in phase-inverting polyphase filter. The measured RMS gain error of the design is smaller than 0.27dB in the desired frequency range.