A 121/145GHz Dual-Band LNA with Single-Path and Dual-Mode Gain-Boosting Core in 28nm 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 wideband gain-boosting technique is proposed, where the embedding is reused in the CM and 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 multi-stage cascaded architecture, enabling gain enhancement while sharpening the gain selectivity between the LB and 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 and HB, respectively.