Linearization of wideband RF Doherty power amplifiers with complex dynamic nonlinearities

In this paper, a traditional look-up-table (LUT) predistorter and a memory polynomial predistorter are applied to a LDMOS Doherty power amplifier to pre-compensate its nonlinearities so as to make its linearity be able to satisfy the requirements of a wideband wireless communication system. The experimental validation results reveal that the widely used memory polynomial cannot effectively suppress the out-of-band spectrum regrowth caused by the complex dynamic nonlinearity of this Doherty power amplifier. In fact, the traditional memoryless LUT predistorter provides unexpected better linearization performance than the memory polynomial predistorter.