An amplifier circuit is configured in such a way that the amplifier circuit includes: a first amplifier to amplify a signal to be amplified; an output matching circuit through which the signal amplified by the first amplifier propagates; and a second amplifier to amplify the signal which has propagated through the output matching circuit, and the output matching circuit is a lumped constant circuit including multiple lumped constant elements, and, by using the multiple lumped constant elements, transforms the impedance seen on the second amplifier side from the first amplifier when the output power of the second amplifier is lower than saturation electric power, to impedance higher than impedance seen on the second amplifier side from the first amplifier when the output power of the second amplifier is equal to the saturation electric power.

A switching circuit comprises a first transistor, a transformer including a first inductor and a second inductor that is co-centric with the first inductor, a first switch, a second switch, a second transistor, a first output, a second output, and coupling circuitry configured to couple the first inductor to the first transistor, a first end of the second inductor, the first switch, and the first output together at a first node, a second end of the second inductor, the second switch, and the second transistor together at a second node, and the second output to the second transistor.