Auxiliary power tracking technique for linearity improvement of a 10 W GaN HEMT PA with and without Power Gate Tracking

This work shows linearity improvement of an 10 W GaN HEMT PA with Auxiliary Power Tracking (APT) technique. It is shown that APT provides higher level of linearity improvement than Auxiliary Envelope Tracking (AET) with 1 percentage point higher PAE. Achieved linearity improvement is 8.8 dB in ACPR and 6.5 percentage points in EVM compared to the reference Class-AB PA. Benefit of the APT over AET is in its limited bandwidth of the drain voltage waveform of only twice the RF bandwidth. In combination with Power Gate Tracking (P-GT), where coefficients of the gate tracking function are optimized for linearity, 11.3 dB better ACPR and 7.28 percentage points better EVM is achieved compared to the reference PA with 1
^st
order polynomial tracking function.