| 摘要 |
PURPOSE:To attain the high efficiency of a power amplifier by connecting a bias circuit using a lambda/4 transmission line to an output matching circuit in consideration of the parasitic element of a semiconductor device. CONSTITUTION:A lambda/4 transmission line 5 is connected to a semiconductor device 3 and an output matching circuit 17 as a bias circuit in order to satisfy the conditions at a juncture 19 to set the impedance at zero to an even-degree higher hamonic wave. the impedance is set at zero with an even degree when an output circuit is viewed from a current source of the device 3 after defining a distance lx between the juncture 19 of the line 5 and an output terminal 8 of the device 3. Therefore the impedance is infinite in terms of a signal frequency when the line 5 is viewed from the juncture 19. This gives no effect at all to an output matching circuit 17.
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