US 2010/0060353 A1Published application

Power amplifier linearization using RF feedback

AssigneeAlcatel Lucent

InventorsAndrei Grebennikov, Florian Pivit

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Abstract

The power amplifier mainly includes a main amplifier, two splitters, one combiner, one subtracter, two phase shifters, one attenuator and one error amplifier. The splitters, subtracter and combiner are designed in the form of 90-degree or quadrature hybrid couplers. A quadrature hybrid can be implemented with any lumped or transmission-line elements and has an important advantage compared to the in-phase splitter that at equal values of reflection coefficients from loads connected to the in phase and 90° phase shift terminals, the reflection wave is lacking at the main input terminal and, consequently, the input voltage standing wave ratio of a quadrature hybrid does not depend on the equal load mismatch level.

Claims7

Dependent claims

A power amplifier having an input connected to a main port of a quadrature hybrid splitter, said quadrature hybrid splitter having an in-phase port coupled to an output of said power amplifier through a main amplifier and another quadrature hybrid, said

quadrature hybrid splitter further having a 90° phase shift port also coupled of said other quadrature hybrid,
wherein said power amplifier further comprises a quadrature hybrid combiner having a main port connected to the in-phase port of said quadrature hybrid splitter and a 90° phase shift
port connected to an input of said main amplifier, an output of said main amplifier being connected to an in-phase port of said other quadrature hybrid,
wherein the 90° phase shift port of said quadrature hybrid splitter is connected to a first input of a subtracter of which an output
is coupled to an isolated port of said quadrature hybrid combiner via a first phase shifter,
wherein said other quadrature hybrid further has a 90° phase shift port coupled to a second input of said subtracter via a second phase shifter,
wherein said other quadrature hybrid further has a main port connected to the output of said power amplifier.

4 more elements

Dependencies are inferred from the claim text.