A 60 GHz Cascode Variable-Gain Low-Noise Amplifier With Phase Compensation in a 0.13 μ m CMOS Technology

A 60 GHz variable-gain low-noise amplifier (LNA) with varactor-based phase compensation is developed using a 0.13 CMOS process. Based on the analysis of the phase variation during the gain control in the cascode-FET unit cell, a simple varactor-based phase compensation method is proposed. A linear bias control scheme for the gate of the common-source FET and the cathode of nMOS varactor at the gate of common-gate FET results in the phase compensation between the two FET's in the cascode cell. The gain control range is also expanded with the proposed approach. The fabricated variable-gain LNA (VG-LNA) shows a small phase variation of 5 ^ over a gain control range of 13 dB.