Patent ID: 7412219

Claim:
A high-frequency amplifier comprising: a first amplifying stage and a second amplifying stage that are disposed in parallel and that amplify VHF/UHF television signals received through an antenna, the first amplifying stage comprising: a first FET and a second FET that are of a grounded-gate type and that are connected in series between a common input terminal and a first output terminal to which a VHF-signal selection circuit is connected, and the second amplifying stage comprising: a third FET and a fourth FET that are of a grounded-gate type and that are connected in series between the common input terminal and a second output terminal to which a UHF-signal selection circuit is connected, wherein switching between amplifying operations of the first and second amplifying stages is performed by an operation switching unit selectively setting one of the first and third FETs in a forward-bias state and the other of the first and third FETs in a reverse-bias state in response to a switching voltage that is externally set.