MULTI-STAGE AMPLIFIER FOR MICROWAVE

PURPOSE:To reduce number of elements of an oscillation prevention circuit by supplying a bias voltage to an input terminal of a transistor(TR) and providing a function of preventing oscillation to a short-stub applying matching and inserting the oscillation preventing resistor to the opposite side of the short- circuit face. CONSTITUTION:A function of preventing oscillation is provided to a short-stub 2 giving a bias voltage to the input terminal of the TR 1 and applying matching and the oscillation preventing resistor 3 is inserted to the opposite side of the short-circuit face. Since almost no current flows to the short-stub 2 supplying the bias voltage and applying matching, even when the oscillation preventing resistor 3 is inserted to the opposite side of the short-circuit face, no voltage drop exists and even when the constant is varied more or less to use the short- stub 2 with the oscillation preventing resistor 3 inserted thereto as the oscillation prevention, bias supply and matching, the characteristic is not affected by matching with a small change of the constant of other elements. Thus, the number of short-stubs and capacitors of the oscillation preventing circuit is reduced.