Open AccessEfficiency and linearity enhancement of a two‐stage X‐band PA through simultaneous gate and drain supply modulation
Author(s) -
Duffy Maxwell R.,
Lasser Gregor,
Cappello Tommaso,
Popović Zoya
Publication year - 2020
Publication title -
iet microwaves, antennas and propagation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.555
H-Index - 69
eISSN - 1751-8733
pISSN - 1751-8725
DOI - 10.1049/iet-map.2019.0970
Subject(s) - linearity , amplifier , modulation (music) , materials science , power (physics) , electrical efficiency , electronic engineering , gallium nitride , optoelectronics , electrical engineering , cmos , physics , engineering , acoustics , layer (electronics) , quantum mechanics , composite material
This study addresses an analogue method for mitigating the non‐linearities introduced by discrete supply modulation of a high‐efficiency power amplifier (PA). A 10 W two‐stage X‐band gallium–nitride monolithic microwave integrated circuit (PA with a peak power‐added efficiency of 55%, is tested with drain supply modulation from 10 to 20 V with an increase in efficiency and substantial degradation in linearity. In this work, the authors characterise the two‐stage PA dynamically to develop shaping functions for both gate bias voltages. They demonstrate that gate modulation can improve back‐off gain and linearity, specifically when gate biases of the two stages of a PA are independently modulated. Simultaneous gate and drain modulation results in 15 percentage point improvement in efficiency over a static supply, and a consistent improvement in noise power ratio over a static supply, for a 20 MHz noise‐like signal. Results with a 20 MHz long‐term evolution signal show comparable improvement in efficiency while maintaining adjacent channel power ratio near the level of the PA with a static supply.