| 摘要 |
PROBLEM TO BE SOLVED: To make a high frequency power amplifier smaller while controlling output of harmonics. SOLUTION: The high frequency power amplifier is provided with a high frequency power transistor(TR) 32, an input matching circuit 35 connected to its control electrode 33, an output matching circuit 36 consisting of a distributed constant line 46 connected to an output electrode 34 of the TR 32 and of a capacitor 47, and a bias circuit consisting of a distributed constant line 48 connected to the output electrode 34, and the output matching circuit 36 and the bias circuit set an output impedance for the third and second harmonics within the range of points A(1.0∠180 deg.), B(0.8∠180 deg.), C(0.8∠225 deg.), D(1.0∠225 deg.) and within the range of points E(1.0∠140 deg.), F(0.8∠140 deg.), G(0.8∠270 deg.) and H(1.0∠270 deg.) respectively on a polar chart. The small-sized high frequency power amplifier with a high efficiency can be realized.
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