2 $\times$ 64-Element Dual-Polarized Dual-Beam Single-Aperture 28-GHz Phased Array With 2 $\times$ 30 Gb/s Links for 5G Polarization MIMO

This article presents a 5G 28-32 GHz 2 × 64-element dual-polarized (DP) dual-beam transmit/receive (TRX) phased array. The array is based on a SiGe 2 × 4 TRX dual-beamformer chip with 6 bits of phase and 25 dB of gain control. The chip delivers 11-12 dBm/channel in the transmit-mode and has a noise figure (NF) of 4.8 dB in the receive-mode. Sixteen chips are employed for the construction of a low-cost printed circuit board (PCB) based 2 × 64-element dual-beam array using flip-chip technology. The phased-array has two 1:16 dual Wilkinson networks and microstrip antennas with rotated feeds for cross-polarization cancellation. The array demonstrates a measured effective isotropic radiated power (EIRP) at Psat of 52 dBm for each beam and is capable of scanning ±50° in azimuth and ±25° in elevation with >28-dB cross-polarization rejection. Simultaneous dual-beam operation is demonstrated with near-ideal patterns for each beam. The array demonstrates independent simultaneously transmitted 2 × 16-quadrature amplitude modulation (QAM) and 2 × 64QAM data streams delivering an aggregate maximum data rate of 2 × 20 and 2 × 30 Gb/s, respectively. Also, measurements done over all scan angles at an EIRP of 41 dBm per polarization and 64-QAM waveforms show a data rate of 2 × 4.8 Gb/s with an EVM ≤ -25 dB. To our knowledge, this is the first demonstration of a dual-polarized dual-beam phased array for 5G polarization-based multiple-input-multiple-output (MIMO) systems with 60-Gb/s maximum data rates.

I. Introduction

Millimeter-wave fifth-generation (5G) new radio (NR) systems currently employ spectrum around 28, 39, and 60 GHz using phased-arrays that can deliver >10 Gb/s of data to each user with low latency [1]–[4]. To further increase the capacity without increasing the modulation order, which comes at the cost of reduced effective isotropic radiated power (EIRP) and very low phase noise requirements, polarization-based multiple-input–multiple-output (MIMO) systems are proposed in the 5G standard. Such systems are also suitable for line-of-sight links with little reflections between the base station and the user.