A V-band variable gain amplifier with low phase variation using 90-nm CMOS technology

A V-band variable gain amplifier (VGA) with wide gain control range, low phase variation, and low return loss variation is designed and implemented on 90-nm CMOS process. Utilizing a phase compensation capacitor at the common gate transistor and a source degeneration inductor at the common source transistor of the cascode configuration, the VGA achieves gain control range of 15.8 dB with only 6.9 degrees transmission phase variation at 60 GHz via simple control mechanism. The maximum small signal gain is 15.8 dB at 60 GHz. In addition, the input/output return losses are insensitivity at different gain state of the VGA. (c) 2014 Wiley Periodicals, Inc.