Alexandre Mallet

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This paper presents a method for the optimization of the power-added efficiency (PAE), as well as the error-vector measurement (EVM) of a 20-GHz power amplifier (PA) applied in this case to the M quadrature and amplitude modulations. A first key point lies in that both input and output biasing voltages of the solid-state power amplifiers (SSPAs) are(More)
Earth observation image-understanding methodologies may be hindered by the assumed data models and the estimated parameters on which they are often heavily dependent. First, the definition of the parameters may negatively affect the quality of the analysis. The parameters could not be captured in all aspects, and those resulting superfluous or not(More)
In this paper, we are interested in estimating parameters entering nonlinear mixed effects models using a likelihood maximization approach. As the accuracy of the likelihood approximation is likely to govern the quality of the derived estimates of both the distribution of the random effects and the fixed parameters, we propose a methodological approach(More)
Images may contain blemishes or artificial structures which come from the processing or directly from the sensors, that decrease the quality of the images and can lead to analysis and interpretation problems. We are interested in detecting these defects automatically. The aim of our method will be to look for artifacts as too regular or too irregular image(More)
Model-order reduction techniques of RF and microwave linear and weakly nonlinear time-varying circuits are presented. The reduced models capture the memory and linear or weakly nonlinear input-output behavior of the circuit, as well as the matching conditions at the model ports. The reported techniques serve to reduce models of a number of RF and microwave(More)
This paper presents a novel and non quasi static behavioral ( black box ) model of power amplifiers. It takes into account nonlinear memory effects for an accurate prediction of signal distortions and power budget in communication systems. The model topology and the model extraction procedure are described. The model proposed in this paper can be derived(More)
This paper discusses the suitability of using a multiport amplifier (MPA) for a power section of space telecommunication payloads with power flexibility requirements. The performances of an MPA-based architecture are compared to those of a classical amplification architecture having one power amplifier per beam. This study is based on a 4 times 4 Ka-band(More)
Characterization of the nonlinear microwave power devices has been considerably enhanced during the last decades. CW stimuli enable to provide valuable and very useful information for the validation of transistor nonlinear models for CAD. They provide also experimental confirmations of the optimum operating conditions of active cells in terms of power, gain(More)