Analysis of the operation of a Hybrid amplifier based on the Doherty amplifier

This paper analyzes the limit points of the backoff region of a Hybrid amplifier with outphasing operation on the low output side and Doherty operation on the high output side. The circuit configuration consists of two parallel Doherty amplifiers connected to a Chireix combiner. The Doherty amplifiers were load-pull simulated, and the Chireix combiner was designed based on the impedance of the obtained backoff efficiency. From the simulation results of the Hybrid amplifier designed using symmetrical and asymmetrical Doherty amplifiers, it was confirmed that the limiting point of backoff efficiency is the drain efficiency of the load-pull data for the configuration in which the Chireix combiner is connected without changing the parameters of the Doherty amplifier.