28 GHz Compact LNAs with 1.9 dB NF Using Folded Three-Coil Transformer and Dual-Feedforward Techniques in 65nm CMOS

This article presents two Ka-band low-noise amplifiers (LNA) for millimeter-wave (mm-wave) phased-arrays. The folded three-coil transformer and EM dual-feedforward techniques are proposed to improve the LNA's noise performance and reduce the chip area. The first two-stage single-ended LNA, consisting of a common-gate (CG) input stage and a common-source (CS) output stage, achieves 1.9 dB minimum noise figure (NF), 16.7 dB peak gain, 4.3 GHz 3-dB bandwidth (BW) from 25.6 to 29.9 GHz, and -12 dBm input 1-dB gain-compression-point (IP1dB) with 13.2 mW Pdc. The second LNA employs the current-reuse topology, which reduces the power consumption to 3.6 mW at the cost of a 0.6 dB NF degradation. The proposed LNAs have been fabricated in 65nm CMOS process. The two LNAs have the same 200 µm × 300 µm core chip area.