A 121/145 GHz Dual-Band LNA with Single-Path and Dual-Mode Gain-Boosting Core in 28 nm CMOS

This paper presents a low-noise amplifier(LNA) that achieves dual-band operation by employing a cascaded single-path and dual-mode gain-boosting amplifier core. The proposed LNA selectively amplifies the low band(LB) under common-mode(CM) excitation and the high band(HB) under differential-mode(DM) excitation. This allows nearly independent tuning per-band and flexible band spacing with a shared signal path and bias condition. To realize this at D-band, a dual-mode gain-boosting technique is introduced, where the embedding is reused in the CM/DM to enhance the gain at the LB and HB, respectively. In addition, a dual-mode inter-stage matching network extends the dual-mode(CM/DM) concept to a cascaded architecture, enabling gain enhancement while sharpening the gain selectivity between the LB/HB. Implemented in a 28 nm CMOS process, the proposed LNA achieves measured peak gains of 19.9/21.9 dB with a 3 dB bandwidth of 19.8/18 GHz in the LB/HB. The measured noise figures are 8.5/8.9 dB for the LB/HB, respectively.