RF POWER AMPLIFIER LINEARIZATION USING PARALLEL RF POWER AMPLIFIERS HAVING INTERMOD-COMPLEMENTING PREDISTORTION PATHS

摘要

An RF power amplifier linearization architecture has a pair of matched RF amplifiers, RF signal paths through which are intercoupled with a phase and amplitude measurement and predistortion mechanism. By selectively combining the RF output of a main path RF power amplifier with the RF input signal supplied to a parallel path RF power amplifier, the predistortion control mechanism of the invention predistorts the RF input signal applied to the parallel path amplifier, so that it includes the same modulated RF carrier component as that applied to the main path amplifier, as well as a complementary version of the intermodulation component of the output of the main path amplifier. The predistortion for each amplifier is controlled such that the resulting RF output signals produced by the matched amplifier pair will have the desired RF carrier modulation component but equal amplitude and phase-reversed intermodulation components. Combining these two matched amplifier outputs in a quadrature hybrid produces a composite signal, in which the desired amplified modulated RF carrier components produced by each matched amplifier constructively sum, while unwanted IMD components cancel.