| 摘要 |
PURPOSE:To attain small-sized and simplified circuit by loading a transmission line whose length is 1/4 wavelength at a signal frequency in parallel with a resistor loaded to an isolation terminal of a directional coupler. CONSTITUTION:The transmission lines 15, 16 whose length (l) is 1/4 wavelength at a signal frequency are connected in parallel with a resistor 6 connected to an isolation terminal of a 1/4 wavelength branching line directional coupler 4. A gate voltage is impressed from a terminal 17, fed to a gate terminal of FETs 1, 1 via a line 15, a drain voltage is impressed from a terminal 18 and fed to the drain of the FET1, 1 via the line 16. On the other hand, the characteristic of the termination circuit of the isolation terminal of the coupler 4 at the signal frequency is not changed by loading the lines 15, 16 so as to provide a function of a bias impression circuit.
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