An X-band CMOS low-noise variable-gain amplifier with interstage reflection-type attenuator

摘要

This letter presents a novel low-noise variable-gain amplifier (VGA) with an interstage reflection-type attenuator. The VGA consists of a common-source amplifier in the first stage for noise reduction, and a cascode amplifier in the second stage for gain enhancement. The built-in attenuator and an inductor are inserted between transistors of the cascode configuration. The attenuator is used for gain variation, and the inductor is used for small gain enhancement and noise reduction. The circuit is designed, implemented, and verified in a standard 0.18-m CMOS process. The VGA consumes 18 mW from a supply voltage of 1.8 V, and achieves 3.7-dB NF, 18.4-dB gain, and -23.5-dBm input P-1dB at 9.2 GHz with good input and output return losses. The VGA provides a 9.3-dB gain variation with 3.7-dB NF in the high-gain mode and 4.6-dB NF in the low-gain mode of the VGA. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:196-199, 2016