A new analog adaptive feed-forward power amplifier

In order to overcome the feed-forward power amplifier linearization performance degradation problem, which caused by the amplitude and phase mismatch or environmental change, this paper proposes a full analog low-pass correlation adaptive feed-forward linear power amplifier. The method adopts large time constant low-pass filter instead of integral filter, and gives the weights control signal by the product operation of reference signal and feedback signal. The method improves the linearization performance and weights convergence speed. A 30MHz-500MHz Ultra-short wave 100w analog adaptive feed-forward power amplifier is designed based on the theoretical analysis. The ADS simulation results show that the third order inter-modulation (IMD3) can achieve to -80dBc, when the two-tone input signal have 100 kHz frequency spacing, and the actual test IMD3 can achieve to -75dBc of the designed feed-forward power amplifier in the condition of laboratory.