| 摘要 |
<p>The present invention provides a technique that allows a plurality of signals having different frequency bands to be accurately amplified. An inter-stage matching circuit (21a) has a plurality of matching circuits used in different frequency bands, any one of the plurality of matching circuits being switched selectively by switches (SW11, SW12, SW13, SW14, SW15) in response to a frequency band of a transmission signal inputted into a power amplifier, so that a connection is established with an input terminal of a bipolar transistor in an output stage. Therefore, a plurality of transmission signals with different frequency bands can be amplified accurately and efficiently since even if the frequency band of the transmission signal changes, a matching circuit corresponding to the transmission-signal frequency band can be connected to the input terminal of the bipolar transistor in the output stage as a consequence of the switches (SW11, SW12, SW13, SW14, SW15) being switched on or off.</p> |
