A novel series diode linearizer for mobile radio power amplifiers

A Flexible Dual-Inflection Point Rf Predistortion Linearizer for Microwave Power Amplifiers

“…Predistortion linearizers [7][8][9][10][11][12][13][14][15][16] are widely used in linearizing the PAs due to, their wide bandwidth, ease of use and their ability to be appended to existing amplifiers as a separate stand-alone module. The predistortion linearizers, in fact, introduce equal and opposite gain and phase distortion at the input of the PA to correct for the actual encountered distortion in the gain and phase characteristics of the final output.…”

“…A linearizer based on a series diode with a parallel capacitor [10] can overcome the limitations of the linearizer reported in [9]. This is a very simple linearizer and utilizes the nonlinearity of the series resistance of the diode, which produces a characteristic positive gain and negative phase with increasing input power.…”

High performance SiGe HBT power unit-cell for S-Band open collector adaptive bias power amplifier design

“…Most power amplifiers are operated in a linear or weakly nonlinear mode, where PAE is much lower when compared to an amplifier driven into saturation. In order to meet the linearity requirements, several published papers have suggested a variety of linearization techniques such as feedback, feedforward, and predistortion to increase the linearity of PA [4][5][6][7]. When a pure resistor bias feed circuit was adopted in PA, the V BE of the main amplifier (power stage) decreases with the increase of input power and results in early gain compression.…”

A predistortion linearizer using a tunable resonator

“…This results in a more linear output and lower distortion at higher power, thus the ability to operate with higher efficiency [2]. Several compact PDs have been proposed using schottky diodes [3], [4] or FETs [5], [6] as the nonlinear device to produce the needed transfer function.…”