Patent ID: 8461929

Claim:
A power amplifier comprising: a first amplifier unit; a second amplifier unit for receiving, along a signal connecting path, a signal from the first amplifier unit and amplifying the signal; and an attenuator connected to the signal connecting path between the first and second amplifier units, wherein the attenuator comprises a plurality of arms, including a first parallel arm and a series arm, and switches connected to the plurality of arms to switch the electrical connection states of the arms with respect to the first and second amplifier units, the first parallel arm and the series arm are arranged, in that order, as viewed from the first amplifier unit toward the second amplifier unit, the first parallel arm is the closest arm, with respect to electrical connection, of the arms to the first amplifier unit and is connected at one end to a connection point on the signal connecting path between the first and second amplifier units, and the series arm follows the first parallel arm, as viewed from the first amplifier unit toward the second amplifier unit, and is connected in series with the signal connecting path between the connection point of the first parallel arm to the signal connecting path and second amplifier unit.