Abstract:

This paper proposes an auto-tuning approach to find the optimal configuration of a dual-input Doherty poweramplifier (DIDPA) to enhance power efficiency while maintaininga good linearity level. The DIDPA configuration consists of a setof circuits and system-level parameters called free-parametersthat are optimized through a hybrid heuristic search control(HHSC), which is the core of the auto-tuning approach. TheHHSC convergence towards the optimal solution is conducted bya cost function designed to present a trade-off between efficiencyand linearity. The HHSC was validated through experimentalusing a 20 MHz LTE signal at 3 GHz, where DIDPA exhibited adrain efficiency (DE) of 60% at an output power level of 36 dBm. The linearizability of DIDPA has been validated through digitalpredistortion (DPD), where the error vector magnitude (EVM) isreduced to 2.5%, and the adjacent channel power ratio (ACPR)is improved to -48 dBc.