A 39-GHz 64-Element Phased-Array Transceiver with Built-In Phase and Amplitude Calibrations for Large-Array 5G NR in 65-nm CMOS

Abstract

This article presents the first 39-GHz phased-array transceiver (TRX) chipset for fifth-generation new radio (5G NR). The proposed transceiver chipset consists of 4 sub-array TRX elements with local-oscillator (LO) phase-shifting architecture and built-in calibration on phase and amplitude. The calibration scheme is proposed to alleviate phase and amplitude mismatch between each sub-array TRX element, especially for a large-array transceiver system in the base station (BS). Based on LO phase-shifting architecture, the transceiver has a 0.04-dB maximum gain variation over the 360° full tuning range, allowing constant-gain characteristic during phase calibration. A phase-to-digital converter (PDC) and a high-resolution phase-detection mechanism are proposed for highly accurate phase calibration. The built-in calibration has a measured accuracy of 0.08° rms phase error and 0.01-dB rms amplitude error. Moreover, a pseudo-single-balanced mixer is proposed for LO-feedthrough (LOFT) cancellation and sub-array TRX LO-to-LO isolation. The transceiver is fabricated in standard 65-nm CMOS technology with flip-chip packaging. The 8TX-8RX phased-array transceiver module 1-m OTA measurement supports 5G NR 400-MHz 256-QAM OFDMA modulation with -30.0-dB EVM. The 64-element transceiver has a EIRPMAX of 53 dBm. The four-element chip consumes a power of 1.5 W in the TX mode and 0.5 W in the RX mode.