Patent ID: 7706835

Claim:
A high-frequency circuit device that is conformable to a system in which a plurality of transmission frequency bands exist, comprising: a transmission amplifier circuit for transmitting high-frequency power from an antenna, which includes at least one high-frequency amplifier for a wide frequency band that amplifies signals in a plurality of transmission frequency bands differing by not less than 200 MHz from each other; a duplexer that is provided for performing simultaneous transmission/reception; upstream and downstream switch circuits in a direction of transmission that are provided so as to sandwich the duplexer between the high-frequency amplifier for a wide frequency band and the antenna and are switched on when the simultaneous transmission/reception is performed; and a power supply amplitude modulator that supplies an amplitude modulation voltage to a power supply terminal of the transmission amplifier circuit, wherein in the high-frequency amplifier of the transmission amplifier circuit, phase information of a transmission signal is supplied to a signal input terminal and the amplitude modulation voltage corresponding to amplitude information of the transmission signal is supplied from the power supply amplitude modulator to the power supply terminal so that polar modulation or polar loop modulation is performed.