Nonlinearity compensation of linear power amplifier for mobile communication

We examines nonlinearity compensation with a 836.5 MHz high efficiency power amplifier. We use the high frequency negative feedback method, which is robust against changes in the amplifier characteristics and whose circuit implementation is easy. The maximum feedback gain of the amplifier is 9 dB. Thus, in the unsaturated region, the distortion is reduced by 9 dB. In the saturated region, an improvement is not obtained due to the reduction of the feedback gain. Computer simulation of the saturated region shows that the feedback amplifier provides a distortion improvement of 10 dB if a feedback gain of 20 dB is achieved. Computer aided design of a feedback amplifier shows an encouraging result for achieving a feedback gain of 20 dB.