| 摘要 |
PROBLEM TO BE SOLVED: To provide an amplifier capable of obtaining high power efficiency and excellent characteristics by easily accomplishing, in simple circuit arrangement, a Doherty amplifier including a plurality of peak amplifier circuits, although there is the problem that it is conventionally difficult to manufacture the Doherty amplifier including the plurality of peak amplifier circuits because of its complicated circuit configuration. SOLUTION: A Doherty amplifier comprises a carrier amplifier circuit 4 and a plurality of peak amplifier circuits 5a, 5b and combines out outputs from these amplifier circuits at a node 7, wherein an impedance converter 6 is provided on an output stage of the carrier amplifier circuit 4 to optimize characteristics of the carrier amplifier circuit, transmission lines 11a, 11b of which the electric length becomes (λ/2)×(n) ((n) is an integer of≥1) are provided on output stages of the peak amplifier circuits 5a, 5b to simplify circuit arrangement, and phase shifters 12a, 12b are provided on input stages of the peak amplifier circuits 5a, 5b to precisely adjust phases of signals on respective routes at a combination point. COPYRIGHT: (C)2009,JPO&INPIT
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