| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a Doherty amplifier which is simply adjusted into an optimal condition. Ž<P>SOLUTION: The Doherty amplifier is constituted of: an RF input A to which an RF signal output from a main amplifier is input; an RF input B to which an RF signal output from a peak amplifier is input; a λ/4 line which synthesizes output signals of two high-frequency amplifiers constituting the Doherty amplifier while adding a 90° phase difference; an impedance converter circuit which converts the impedance of the synthesizing part of the λ/4 line to an output load impedance; a power source line connected to the impedance converter circuit; a DC switch A which is inserted between the RF input A and the λ/4 to switch operation to OPEN or SHORT with a control voltage VcontA; a DC switch B which is inserted between the RF input B and the synthesizing part of the λ/4 and the impedance converter circuit to switch operation to OPEN or SHORT with a control voltage VcontB; and a harmonic control circuit which is connected with the power source line and suppresses distortion. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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