Fully integrated Doherty power amplifier electromagnetically optimized in CMOS 65nm with constant PAE in backoff

A fully integrated Doherty power amplifier at 2.535 GHz is presented in 65 nm CMOS technology with constant PAE over a 8.75dB backoff. Electromagnetic models of each layout path were included in the optimization to dimension circuit components regarding parasitics of an accurate model. The method increased the PAE level in 6% through a constant 8.75 dB backoff range and increased in 2 dB the output power. The amplifier has an output power of 24 dBm, the first PAE peak is 26% and the second one 27%. Both sub-amplifiers have a single-ended cascode topology and optimized input and output networks to reduce the number of inductances and to correctly balance active-loadpull effect. Comparisons were done between schematic, post-layout and electromagnetic simulation.