Linearization of two-way Doherty amplifier by injection of second and forth order nonlinear signals at the input and output of the carrier cell

Abstract

In this paper two-way Doherty amplifier with the additional circuit for linearization has been realized and measurements of the linearization influence to the third-and fifth-order intermodulation products have been carried out. The linearization approach uses the fundamental signals' second harmonics and fourth-order nonlinear signals that are extracted at the output of the peaking cell, adjusted in amplitude and phase and injected at the input and output of the carrier cell in Doherty amplifier. 

Design of RF amplifier with enhanced performance

“…In recent years, some new linearization methods such as using special predistortion [1,2], compensating pre-postdistortion [3,4], harmonic/intermodulation injection [5,6] and active auxiliary compensation [7][8][9][10] have been reported. Among these new techniques, due to its significant advantages for fully monolithic design, the active auxiliary compensation has received a great deal of attention.…”

High frequency CMOS amplifier with improved linearity

“…It is important and pressing to design monolithic high frequency amplifiers with high gain accuracy, good linearity and wide bandwidth in modern communication circuits and systems. Some new methods have been reported in recent years to achieve different levels of linearity by using special predistortion [1][2][3][4][5][6][7][8], compensating pre-post-distortion effect [9,10] or harmonic/ intermodulation injection [11][12][13][14][15][16]. These methods focus on reducing the distortion at the source end, making them more efficient than the traditional linearisation techniques.…”