A K-Band Dual-Mode Common Gate Cross-Summing VG-LNA With Low Phase Variation

Abstract

This brief presents a variable-gain low-noise amplifier (VG-LNA) with a common gate (CG) cross-summing configuration, which is fabricated using a 65-nm RF CMOS process. It has a wide gain control range as well as a high input 1 dB gain compression point (IP1dB) at high-gain by introducing a split common-gate transistor (SCGT) technique. In addition, output phase compensation is achieved by adopting a tuning capacitor at the cascode node. This LNA is designed as 2-stage cascode, and the area excluding the pad is 0.2 mm(2). It consumes 25.2 mW with a 1.2-V power supply. It shows a gain of 25 dB and a noise figure of 3.4 dB at 22 GHz. The measured minimum IP1dB is -27.5 dBm, and the root-mean-square phase error is 0.34 degrees over the gain control range of 14 dB at 22 GHz.