A 28-/39-GHz Dual-Band CMOS LNA With Shunt-Series Transformer Feedback

This letter presents a concurrent dual-band low-noise amplifier (LNA) operating at 28 and 39 GHz for multiband 5G wireless systems. In order to achieve a wideband input power matching, the LNA adopts a shunt-series feedback structure. Detailed noise analysis of the shunt-series transformer feedback LNA is proposed to guide the noise-optimized design, and a modified input network is proposed to improve the noise matching. The modified method also enhances the transconductance of the input stage, thus suppressing the noise of the subsequent circuit and obtaining a better overall noise figure (NF). Based on this input structure, a dual-band LNA with excellent NF is designed in a 65-nm complimentary metal–oxide–semiconductor (CMOS) process. This dual-band LNA achieves 18.1/18.4-dB gain and 3.1/3.8-dB NF at 28/39 GHz, consuming 10.2 mW from a 1.0-V power supply.