Graded-Channel GaN-Based HEMTs for High Linearity Amplifiers at Millimeter-Wave

Abstract

Linearity in low-noise amplifiers is critical for high-performance mm-wave systems. While GaN-based HEMTs offer excellent survivability and noise figure, conventional AlGaN/GaN device designs exhibit only modest linearity. The use of graded-channel structures is promising for increasing the linearity figure of merit, OIP3/PDC, to 20 dB or more. We report simulation studies for further enhancement in linearity performance. By combining non-linear channel compositional grading with the parallel connection of multiple transistors for third-order transconductance cancellation, a further increase of 7 dB in linearity figure of merit beyond that experimentally demonstrated for linearly-graded channel devices is projected.