A 24–29.5-GHz Highly Linear Phased-Array Transceiver Front-End in 65-nm CMOS Supporting 800-MHz 64-QAM and 400-MHz 256-QAM for 5G

Abstract

This article presents a four-element phased-array transceiver (TRX) front-end for millimeter-wave (mm-Wave) 5G new radio (NR). The effects of amplitude-to-phase (AM–PM) and amplitude-to-amplitude (AM–AM) distortions on error vec- tor magnitude (EVM) are detailed. A three-stage highly linear wideband class-AB power amplifier (PA) is described, miti- gating AM–PM and AM–AM distortions without degrading other performances. A matching network embedded transmit- ting/receiving (T/R) switch is proposed to support time division duplex (TDD). With the proposed technique, RF switch insertion losses are reduced in both transmitter (TX) and receiving (RX) modes. In each TRX element, phase and gain controls are achieved by a 6-bit vector-modulated phase shifter (VMPS) with a phase tuning range of 360 ◦ and a 6-bit attenuator with a gain tuning range of 31.5 dB, respectively. Fabri- cated in 65-nm bulk CMOS, the proposed packaged TRX demonstrates the measured peak gains of 25.5/14.2 dB with the gain ripples of less than 2.5/1.9 dB across 24–29.5 GHz in the TX/RX mode. The measured peak P 1d B is 17.6 dBm with a power added efficiency (PAE) of 20.4%. The measured minimum noise figure (NF) is 4.3 dB. The TRX achieves an output power of 7.9–8.9 dBm and an EVM of −25 dB with 8 × 100-MHz 5G NR frequency range 2 (FR2) orthogonal frequency division mul- tiplexing (OFDM) 64-quadrature amplitude modulation (QAM) signals across 24–29.5 GHz, covering 3rd generation partnership project (3GPP) 5G NR FR2