| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor amplifier that easily operates at high efficiency in a microwave band.SOLUTION: The semiconductor amplifier includes a semiconductor amplification element, an output terminal, an output matching circuit and an output bias circuit. The output matching circuit includes a bonding wire, a first transmission line having first characteristic impedance and a first electric length, and a second transmission line having second characteristic impedance and a second electric length. An end of the first transmission line is connected to one end of the second transmission line. The other end of the second transmission line is connected to the output terminal. The output bias circuit includes a third transmission line of which the electric length becomes 90° substantially, a ground capacitor and a power supply terminal. The third transmission line includes one end that is connected at a position where the electric length becomes 45° substantially in the second transmission line, and the other end connected to the ground capacitor. The first electric length is 90° or less in an upper limit frequency.SELECTED DRAWING: Figure 1 |
