A 27–46 GHz Low Noise Amplifier With Dual-Resonant Input Matching and A Transformer-Based Broadband Output Network

This paper presents a 27–46GHz LNA. Two circuit innovations are proposed 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 the input matching, and thus extend the input matching bandwidth. Second, a network synthesis methodology is adopted to convert canonical second-order bandpass filter into a on-chip transformer to achieve broadband power gain. In the measurements, the 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 is limited by the 10-dB return loss bandwidth, which is from 27 to 46 GHz. The minimum NF is 2.4 dB at 27.8 GHz, and the NF is < 4.2 dB within the bandwidth. The IIP3 is -11.0 dBm at 38 GHz with a dc power consumption of 25.5 mW.