| 摘要 |
PURPOSE:To attain respectively excellent amplification operation at plural bands by matching the impedance by a bias supply circuit at a band lower than the frequency band subjected to impedance matching. CONSTITUTION:An amplifier element 5 is coupled with an input terminal 1 and an output terminal 3 with strip lines 2, 4 and the impedance is matched at the 1st frequency band, e.g. 11-13GHz by impedance matching circuits 6, 7. Further, the bias supply circuit to the amplifier element 5 is constituted by strip lines 8, 9 and the line length is decided to be a 1/4-wavelength at said 1st frequency band, then the impedance is nearly infinite. Capacitors 11, 12 are provided respectively to the lines 8, 9 and the value is adjusted so as to take matching at the 2nd frequency band, e.g. 1-3GHz lower than the 1st frequency band.
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