| 摘要 |
PURPOSE:To obtain a stable characteristic over a wide range with a miniature structure in the titled circuit by providing an output matching circuit at a place near the drain terminal of an FET as well as an input maching circuit at a place near the gate terminal of the FET and at the same time providing a pair of stub lines at a place distant away from both matching circuits by a prescribed distance. CONSTITUTION:Matching circuits 7a1 and 7b1 are provided at the places near a train terminal 21 of an FET5a and a gate terminal 22 of an FET5b respectively. Then a stub line 24 which has a short circuit impedance with approximately center frequency of a signal band is provided to a transmission line 23 together with a stub line 25 which has the capacitiveness to eliminate an inductive component. The distance between a pair of these stub lines and both matching circuits 7a1 and 7b1 is selected at about 1/4 wavelength of the center frequency of a desired band. As a result, a conventional transmission line having about 1/2 wavelength of the center frequency of the desired band can be substantially ignored. Thus the conventional stub lines formed at both ends of said transmission line can be replaced with the lines 24 and 25. Then the coincidence is obtained between the synthetic induction quantity of lines 24 and 25 and the synthetic capacity of the replaced lines. Thus a connection of low VSWA is obtained as conventional. In addition, it is possible to set amplifying circuits 2a and 2b with a short distance.
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