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A linearization technique that uses the injection of the

In this article, a single‐stage power amplifier and two‐way Doherty amplifier are linearized by the technique that uses second harmonics and fourth‐order nonlinear signals. Measurements of the linearization effects on the third‐ and fifth‐order intermodulation products have been carried out. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:425–430, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27294

Verification of two linearization methods, applied on asymmetrical two-way microstrip Doherty amplifier in experiment and on symmetrical two-way Doherty amplifier in simulation, is performed in this paper. The laboratory set-ups are formed to generate the baseband nonlinear linearization signals of the second-order. After being tuned in magnitude and phase in the digital domain the linearization signals modulate the second harmonics of fundamental carrier. In the first method, adequately processed signals are then inserted at the input and output of the main Doherty amplifier transistor, whereas in the second method, they are injected at the outputs of the Doherty main and auxiliary amplifier transistors. The experimental results are obtained for 64QAM digitally modulated signals. As a proof of concept, the linearization methods are also verified in simulation, for Doherty amplifier designed to work in 5G band below 6 GHz, utilizing 20 MHz LTE signal.

A simple procedure for extraction the intrinsic noise wave temperatures in the wave representations of microwave transistors is presented in this paper. A set of equation describing the noise parameters as the function of three equivalent noise temperatures is implemented within the circuit simulator Libra. After that, the wave noise model is defined as new user-defined element of program Libra library. Good agreement between modeled and measured noise parameters is observed.

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The linearization effects on two-way Doherty amplifiers are presented in this paper. Symmetrical Doherty amplifier with the additional circuit for linearization has been realized and measurements of the linearization influence on the third- and fifth-order intermodulation products have been carried out. Asymmetrical Doherty amplifier has been designed and effects of the applied linearization technique have been considered through the simulation process. 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. [Projekat Ministarstva nauke Republike Srbije, br. TR-32052]

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