| 摘要 |
PURPOSE: Application of the doherty amplifier as a predistortion circuit for linearizing microwave amplifiers is provided, which uses Doherty amplifier to precompensate for gain compression and phase expansion as the input power level is increased while simultaneously reducing the intermodulation(IM) distortion. CONSTITUTION: The microwave power amplifier(20) includes a carrier amplifier(22) and a peak amplifier(24). Both the carrier amplifier(22) and the peak amplifier are formed from heterojunction bipolar transistors(HBT)(22) and in particular as a prematched 1.5x 30£mu|m x four finger InP DHBT device with a total emitter area of 180£mu|m.
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