| 摘要 |
The present invention provides a radio frequency power amplifier which may not introduce radio frequency loss during switching power amplifier units between high and low output power levels. By connecting a first-stage matching network M 12 and first-stage matching network M 13 to respective output nodes of a power amplifier unit A 11 and power amplifier unit A 12 that either one operate by switching, connecting the output nodes of the first-stage matching network M 12 and M 13 in parallel, connecting a last-stage matching network M 11 between the junction of M 12 and M 13 and the output terminal OUT, the first-stage matching networks M 12 , M 13 , and last-stage matching network M 11 are formed, for both power amplifier units A 11 and A 12 , so that impedance matching is established between the output terminal OUT and the power amplifier unit in operation when one unit is in operation the other is in stop of operation. The present invention allows switching from one power amplifier unit to the other without the need of a radio frequency switch.
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