an circuit and method are provided for amplifying rf input signal to produce rf output signals with third - order intermodulation distortion products . the circuit and method use a feedback signal to control the bias voltage of the amplifier , such that the output third - order intermodulation distortion product increases monotonically with the rf input signal power . specifically , the third - order intermodulation distortion product responds over a predetermined output power range by increasing three decibels in response to each one - decibel increase in input power .