A K/Ka/V Triband Single-Signal-Path Receiver With Variable-Gain Low-Noise Amplifier and Constant-Gain Phase Shifter in 28-nm CMOS

This article presents a single-signal-path tri (K/Ka/V)-band receiver (RX) featuring area/cost-effective support for various millimeter-wave phased-array applications. A triple-coupling transformer (TCT) at the common-gate input stage of the RX low-noise amplifier (LNA) is proposed for triband impedance matching and g
_m
-boosting. By augmenting each low-parasitic pMOS switched inductor load with a pMOS variable resistor in parallel, the variable-gain functionality is merged into this LNA to cover a wide input-signal range in a low-overhead manner. An active single-balanced mixer (SBM) for radio frequency (RF)-intermediate frequency (IF) downconversion is adopted to eliminate a wideband balun. Poor RF-IF and local-oscillator (LO)-IF isolations and low IIP
₂
normally inherited in an SBM are avoided by setting the IF particularly. The wideband response of an on-chip LO buffer is realized through input resistor coupling and output inductor peaking. Furthermore, a constant-gain phase shifter (CGPS) at IF is proposed to benefit the orthogonal gain-and-phase control preferred by beam steering. This CGPS uses an amplitude-only feedback loop to retain the gain without baseband equalization. Fabricated in a 28-nm bulk CMOS technology, this RX exhibits variable power gains of 12.5-33.2 dB (at 24 GHz), 13.4-34.6 dB (at 33 GHz), and 3.1-32 dB (at 50 GHz) with respective minimum noise figures of 4.78, 5.12, and 6.15 dB. The respective RX 3-dB bandwidths are 20-27, 30-34.6, and 42-55.5 GHz. The measured CGPS gain variation at IF (2-4 GHz) is within 0.94 dB. This RX consumes 131 mW and occupies 1.22 mm
²
with pads in a silicon area.