HIGH FREQUENCY AMPLIFIER

PROBLEM TO BE SOLVED: To provide a high frequency amplifier that facilitates arrangement of a second harmonic reflecting circuit and also facilitates arrangement of other things than the second harmonic reflecting circuit while maintaining the advantage that a high frequency transistor operates with high efficiency by arranging the second harmonic reflecting circuit very near a signal input electrode of the high frequency transistor.SOLUTION: The second harmonic reflecting circuit which resonates with a second harmonic of an input signal is formed of inductance by a transmission line 5b and a source via hole 4a, and an MIM capacitor 6, so the second harmonic reflecting circuit can be arranged very near a gate electrode 1 of a transistor, which thereby operates with high efficiency. Further, the transmission line 5b and the MIM capacitor 6 are connected in this order to the gate electrode 1 of the transistor, so only the thin transmission line 5b is connected to the gate electrode 1 and the MIM capacitor 6 of large size is not connected. Consequently, the arrangement of the second harmonic reflecting circuit is facilitated and the arrangement of other things than the second harmonic reflecting circuit is also facilitated.