A Multi-Band 16–52-GHz Transmit Phased Array Employing 4 × 1 Beamforming IC With 14–15.4-dBm Psat for 5G NR FR2 Operation

This article introduces a millimeter-wave (mm-wave) multi-band transmit (Tx) phased-array design supp- orting the fifth-generation (5G) new radio frequency range 2 (NR FR2) bands. An eight-element phased-array module is presented employing two wideband 16–52 GHz $4{\times }1$ Tx beamformer chips and tapered slot Vivaldi antenna array. The beamformer chips are designed in a SiGe BiCMOS process and flipped on a printed circuit board (PCB). The SiGe integrated circuit (IC) has four differential radio frequency (RF) beamforming channels each consisting of an active balun, analog adder-based phase shifter (PS), variable gain amplifier (VGA), and a two-stage class-AB power amplifier (PA). The RF input signal is distributed to the four channels using a compact Wilkinson network. The measured peak gain is 28.3 dB with 13.5–14.7 dBm output $P_{1{\mathrm {dB}}}$ and 14–15.4 dBm $P_{{\mathrm {sat}}}$ at 20–50 GHz. Each channel dissipates 250 mW from 2 V and 3-V supplies at $P_{1\,{\mathrm{ dB}}}$ . The beamformer chip is tested using 64-QAM waveforms and achieves a data rate of 2.4 Gb/s at 5.2% rms EVM and 9.6-dBm average power. The eight-element phased-array module shows a broadband performance with excellent patterns and ±60° scanning capability and with a peak effective isotropic radiated power (EIRP) of 32–34 dBm at 19.5–51 GHz. At an EIRP of 21–22 dBm, 400-MHz 256-QAM 5G-NR compliant waveforms are transmitted with < 2.98% EVM demonstrating 5G NR FR2 operation. To the author’s knowledge, this work achieves the highest bandwidth phased array with a peak EIRP of 34 dBm enabling the construction of multi-standard/multi-band 5G phased-array systems.

I. Introduction

The pace of millimeter-wave (mm-wave) communication systems development is accelerating and is motivated by the rapid deployment of fifth-generation (5G) networks worldwide to meet the high-data-rate demands. Several mm-wave bands have already been standardized as part of the 5G new radio frequency range 2 (NR FR2), including n257 band (26.5–29.5 GHz), n258 band (24.25–27.50 GHz), n259 (39.5–43.5 GHz), n260 band (37–40 GHz), and n261 band (27.5–28.35 GHz) [23]. Also, several regions globally started or planned auctions in FR2 for 26-, 39-, and 47-GHz bands. This widespread spectrum requires a multi-band/multi-standard solution capable of supporting current and future bands and enabling key features, such as network roaming and interband carrier aggregation.