Patent ID: 8830000

Claim:
A multi-band amplifier comprising: a wireless signal input terminal into which a first frequency band signal and a second frequency band signal are input; a first impedance matching part connected to the wireless signal input terminal and configured to match an input impedance in a first frequency band; a second impedance matching part connected to the wireless signal input terminal and configured to match an input impedance in a second frequency band; a first cascode amplifier constituted by a first common source amplifier to which the first impedance matching part and the second impedance matching part are connected, and a first common gate amplifier connected to the first common source amplifier and including a third transistor to which a first common gate control signal is input into a control terminal; and a second cascode amplifier constituted by a second common source amplifier to which the first impedance matching part and the second impedance matching part are connected, and a second common gate amplifier connected to the second common source amplifier and including a sixth transistor to which a second common gate control signal is input into a control terminal.