CIRCUIT FOR IMPROVING EFFICIENCY OF RF AMPLIFIER, CAPABLE OF SECURING HIGH OUTPUT EFFICIENCY BETWEEN HIGH RF OUTPUT RANGE AND LOW RF OUTPUT RANGE

摘要

PURPOSE: A circuit for improving efficiency of an RF amplifier is provided to enhance the performance and the efficiency by obtaining a high output between a high RF output range and a low RF output range. CONSTITUTION: A high power amplifier(22A) is branched from an input matching unit(21) and is operated at a high power mode. A low power amplifier(22B) is branched from the input matching unit and is operated at a low power mode. A high power output matching unit(23A) performs an impedance matching process for an output terminal of the high power amplifier and an RF output terminal. A low power output matching unit(23B) performs an impedance matching process for an output terminal of the low power amplifier and the RF output terminal. A switch is used for performing a switching operation between an output terminal of the high power output matching unit and the RF output terminal. A λ/4 transformer(24) is used for minimizing an influence of the low power output matching unit to the high power output matching unit.