28 GHz Compact LNAs With 1.9 dB Minimum NF Using Folded Three-Coil Transformer and Dual-Feedforward Techniques for Phased Array Systems

This article presents two Ka-band low-noise amplifiers (LNA) for millimeter-wave (mm-wave) phased-arrays. The folded three-coil transformer and electrical-magnetic (EM) dual-feedforward techniques are proposed to improve the LNA's noise performance and reduce the chip area. Design procedures targeting compact chip area, low noise, and high gain are provided. 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 power consumption. The second LNA employs the current-reuse topology based on the first LNA, which reduces the power consumption to 3.6 mW at the cost of 0.6 dB NF degradation. The proposed LNAs have been fabricated in 65 nm CMOS process. The two LNAs have the same 200 $\mu $ m $\times$ 300 $\mu $ m core chip area. To the best of our knowledge, the first LNA shows the lowest NF and smallest core area at 28 GHz compared with the published CMOS works in a similar frequency range.