| 摘要 |
A front-end amplifier has an impedance detector that detects an impedance seen looking into an antenna side from a power amplifier from a radio-frequency signal output from the power amplifier and a radio-frequency signal reflected from the antenna, in which a control circuit decides on whether the impedance detected by the impedance detector belongs to a specific region or not, and controls, if the impedance belongs to the specific region, at least one of the bias condition of the power amplifier and the impedance of a variable-matching circuit. |
