LINEAR RF POWER AMPLIFIER WITH FREQUENCY-SELECTABLE IMPEDANCE MATCHING

摘要

A radio frequency (RF) amplifier circuit includes a first impedance matching circuit configured to receive an input RF signal, a control circuit configured to produce a band control signal according to the frequency of the input RF signal, an RF amplifier having its input connected to the first impedance matching circuit. The RF amplifier can produce an amplified RF signal in response to the input RF signal. A second impedance matching circuit can receive the amplified RF signal from the RF amplifier. At least one of the first impedance matching circuit and the second impedance matching circuit has an impedance that is adjustable by the band control signal. A multi-band filter can switch the amplified RF signal from the second impedance matching circuit to one of selectable narrow-band filters in response to the band control signal.