A novel linearization technique for RF power amplifiers is presented in this paper. The proposed technique uses the modified baseband signal that modulates the fundamental carrier second harmonic. This additional signal processed for linearization is then injected, together with the fundamental useful signal, at the input of the amplifier transistor. Also, a prepared signal for linearization is inserted at the amplifier transistor output. In-phase and quadrature-phase components of the modified baseband signal are formed as the products of the second order nonlinearity of a nonlinear system fed by the useful baseband signal. The effects of the proposed linearization method are considered on a single stage power amplifier for quadrature amplitude modulated signals at different input power levels going up to 1dB below saturation region, as well as for WCDMA digitally modulated signal.

No abstract

No abstract

The linearization of a broadband two-way microstrip Doherty amplifier designed for application in the frequency range 0.9-1.0 GHz is considered in this paper. The amplifier characterized by the maximum output power 8 W is designed in microstrip technique for broadband applications. For linearization purposes, the second-and fourth-order nonlinear signals are extracted at the output of the peaking cell, adjusted in amplitude and phase and fed at the input and output of the carrier transistor over the microstrip hairpin band-pass filters. The effects of the linearization are considered through the simulation for two sinusoidal signals with different frequency interval between them setting on from 5 MHz and going up to30 MHz at different input power levels up to saturation, as well as for an Orthogonal frequency division multiplexing (OFDM) digitally modulated signal.

No abstract