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Extraction of a Multi-Dimensional Polynomial Device Model for an Improved Distortion Contribution Analysis Technique

Aikio, J A ; Rahkonen, T. R. ; Pedro, J. C.

IEEE Trans. on Microwave Theory and Tech. Vol. 63, Nº 1, pp. 155 - 164, January, 2015.

ISSN (print): 0018-9480
ISSN (online): 0018-9480

Journal Impact Factor: 2,711 (in 2008)

Digital Object Identifier: 10.1109/TMTT.2014.2367530

Abstract
This paper presents a method to characterize a multidimensional
polynomial current and charge source models needed
for a distortion contribution analysis technique that can identify
the dominant nonlinearities and different mixing mechanisms. A
separate model characterization step with carefully chosen test signals
is used to break the inherent input–output correlation that
otherwise complicates the model fitting. The proposed Volterraon-
top-of-harmonic-balance technique and improved polynomial
fitting are then verified through the analysis of a 100-W LDMOS
RF Doherty amplifier, which showed that, in this circuit, the cubic
nonlinearity of the gate capacitance is the main culprit of AM–PM
distortion.