Doherty amplifier
AssigneeSumitomo Electric Device Innovations, Inc.
InventorsAndrey Grebennikov, James Wong, Naoki Watanabe
Life of this patent
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Abstract
An inverted symmetrical four-stage Doherty amplifier is disclosed. The Doherty amplifier includes a carrier amplifier and a plurality of peak amplifiers. Outputs of the carrier amplifier and the peak amplifiers are provided to the combining unit through the offset unit including offset transmission lines each connected with the carrier amplifier and the peak amplifiers. The offset transmission lines have characteristic impedance and electrical lengths equal to each other such that the impedance seeing the amplifiers at the ends of the offset transmission lines become substantially short-circuited.
Claims6
A Doherty amplifier including a carrier amplifier and a plurality of peak amplifiers, comprising:
- an input splitter that evenly distributes an input radio frequency (RF) signal to the carrier amplifier and the plurality of peak amplifiers;
- an amplifying unit that includes the carrier amplifier and the plurality of peak amplifiers;
- an offset unit that includes a plurality of offset transmission lines each connected with the carrier amplifier and the peak amplifiers;
- and
- an output combiner that combines outputs of the carrier amplifier and the peak amplifiers each provided through the offset transmission lines;
- wherein the offset transmission lines have characteristic impedance and electrical lengths substantially equal to each other, the offset transmission lines convert output impedance of the peak amplifiers into a short-circuit when the peak amplifiers are turned off.
Dependencies are inferred from the claim text.