Analysis, simulation, and measurement of envelope tracking linearization

Additional intermodulation distortions (IMD) are generated in an envelope tracking (ET) power amplifier (PA) due to the mixing between RF input and ET signals. ET linearization can thus be achieved by the IMD cancellation. Analytical expressions depicting the ET linearization mechanism are derived. IMD cancellation is demonstrated with a three tone harmonic balance simulation. Significant linearity improvement is experimentally observed with both two-tone and modulated signals.