A Doherty power amplifier (DPA) is an effective structure born in 1936 which, after a scarce revival around year 2000), had been strengthened from 2005 because its capability to combine linear amplification with power efficiency. Despite the conceptual simplicity of its basic operation, a lot of practical drawbacks shrink the theoretical behavior, thus leading a significant number of research w...

In modern transmitting devices the digital predistortion technique is widely used for linearizing the power amplifier. There are many algorithms realizing predistortion technique with a different complexity and a stability of results. The several methods are described and compared. The orthogonal polynomials with memory were has proved to be simple enough with suitable results, so it was chosen...

A novel approach is proposed for automated dimension estimation in memory polynomial based power amplifiers/transmitters behavioral models. This method consists of successively identifying the static nonlinearity order and memory depth of the model in accordance with a predefined performance criterion. The proposed method is validated using a 3G Doherty power amplifier driven by various WCDMA s...

Presently there exists a great demand for wireless systems that achieve high data transmission rates while using as little power and bandwidth as possible. Maximum data transfer for a given channel width demands sophisticated modulation techniques, the best of which require a linear power amplifier (PA). The strong tradeoff between linearity and power efficiency in PA’s has motivated research i...

In this paper we present measured inand output data of a power amplifier (PA). We compare this data with an AM-AM and AM-PM model. We conclude that a more sophisticated PA model is needed to cope with severe memory effects. We suggest to use memory polynomials and introduce two approaches to deduce the polynomial coefficients from the measured data: the Least-Squares and Crosscorrelation approa...

The objective of this research was to design a 2.4 GHz class AB Power Amplifier (PA), with 0.18um Semiconductor Manufacturing International Corporation (SMIC) CMOS technology by using Cadence software, for health care applications. The ultimate goal for such application is to minimize the trade-offs between performance and cost, and between performance and low power consumption design. This pap...

Optical communication links are usually made with erbium-doped fiber amplifiers, which amplify the signal waves in a phase-insensitive (PI) manner. They can also be made with parametric fiber amplifiers, in which the signal waves interact with idler waves. If information is transmitted using only the signals, parametric amplifiers are PI and their noise figures are comparable to those of erbium...

This paper is focused on a model for the power amplifier considering the memory effects in short terms, this work was developed for periodic signals through Matlab software and was implemented in Simulink. This model for the power amplifier implements a Memory-Polynomial models. Memorypolynomials prove to be both accurate and easy to implement and was compared with Ghorbani and Saleh quasi-memo...

This paper presents results of investigation on the effects of technology on the performance of the class E power amplifier circuit. A typical class E circuit has been designed and simulated, for a typical UMTS Tx frequency (1.95 GHz) and output power ( 27dBm). Three different technologies have been used (silicon BJT, CMOS and GaAs HBT) and several important parameters (output efficiency, power...

The Cartesian feedback technique is an extended solution for reducing the distortions generated by the nonlinearities of power RF amplifiers, being its restrictions of use related to the stability margins of the lineariser loop. Here, considerations are given to its use in the Ka-band, where the small wavelengths lead to critical times and phase unbalances which produce misadjustments of the fe...