A 0.25–1.7-GHz, 3.9–13.7-mW Power-Scalable, −10-dBm Harmonic Blocker-Tolerant Mixer-First RF-to-Digital Receiver for Massive MIMO Applications

To be cost-effective and energy-efficient, massive multiple-input multiple-output (MIMO) arrays must be constructed from radio elements with low power and high linearity, but can tolerate higher noise than conventional stand-alone radios. This letter presents a low-power 0.25–1.7-GHz power- and resolution-scalable mixer-first receiver tailored for variable-element massive MIMO systems with digital beamforming. The receiver includes tunable mixer size and harmonic recombination, dissipates 3.0–12.1 mW (at 1 GHz) with 13.6–19-dB noise figure (NF) while tolerating −10 dBm nearby/harmonic blockers. Two scalable 0.4–0.8-mW, 7.0–9.1-ENOB, 80-MS/s SAR analog-to-digital converters complete the RF-to-digital receiver. When used in large arrays, this configurable receiver can utilize array-level noise averaging to maintain nearly constant array-level power consumption and NF even as the array size grows by a factor of four from 16 to 64 elements, while maintaining good linearity.