Patent ID: 8478334

Claim:
A wireless terminal device comprising: a first casing including an antenna; a second casing movably connected to the first casing; a baseband processing unit that generates a transmit signal; a plurality of amplifiers that amplify the transmit signal; a first switch provided on each transmission path connecting the antenna and each of the amplifiers; a second switch provided between the transmission path and a ground, where the second switch is turned ON when a first predetermined voltage is applied, is turned OFF when a second predetermined voltage is applied, and, when an intermediate voltage between the first predetermined voltage and the second predetermined voltage is applied, has a capacitance according to the applied intermediate voltage; an impedance acquisition unit that acquires an impedance of the antenna corresponding to a positional relationship of the first casing and the second casing; and a control unit that turns ON one of the first switches based on a frequency band of the transmit signal and applies the intermediate voltage to at least one of the second switches to match an impedance of the amplifier arranged on the transmission path where the first switch is turned ON and the impedance of the antenna based on the impedance of the antenna acquired by the impedance acquisition unit.