A broad-band linear amplifier circuit includes a driver amplifier to produce a first amplified radio frequency (RF) signal in a first single RF band in response to a first input RF signal and to produce a second amplified RF signal in a second single RF band in response to a second input RF signal. The first single RF band and the second single RF band reside in a broad band that has a bandwidth more than two times a bandwidth of the first single RF band or the second single RF band. A sensing circuit can sense a power, a gain, or a phase of the first output RF signal and the second output RF signal, and to produce a sensing signal. A gain control circuit controls gain variation of the driver amplifier in response to the sensing signal.