A 2746-GHz Low-Noise Amplifier With Dual-Resonant Input Matching and a Transformer-Based Broadband Output Network

This letter presents a 27-46-GHz low-noise amplifier (LNA) in a 45-nm CMOS silicon-on-insulator (SOI) process. Two circuit techniques are employed to enhance the LNA bandwidth. First, the intrinsic gate-to-drain parasitic capacitance of the input transistor and the frequency-dependent behavior of the first-stage load impedance are explored to realize dual resonances for S-11, thus extending the input matching bandwidth. Second, a network synthesis methodology is presented to convert a canonical second-order bandpass filter to a transformer-based output network, which realizes broadband power gain while occupying only one inductor footprint. In the measurements, the LNA 3-dB gain bandwidth is from 25.5 to 50 GHz with a peak gain of 21.2 dB at 37.8 GHz. The effective bandwidth of the LNA is limited by the 10-dB return loss bandwidth, which is from 27 to 46 GHz. The minimum noise figure (NF) is 2.4 dB at 27.8 GHz, and the NF remains <4.2 dB within the effective bandwidth. The measured IIP3 is -11.0 dBm at 38 GHz with 25.5-mW dc power consumption.