Dual-Input Driving Strategies for Performance Enhancement of a Doherty Power Amplifier

The aim of this work is to assess the performance improvement offered by several driving strategies of a dual-input digital Doherty power amplifier with respect to the equivalent single-input topology. To offer a fair comparison, an analog amplifier and the equivalent digital version, which is equal in all parts except for the absence of the input power divider, are designed at 3.5 GHz. The flexibility of a dual-input control allows to implement power-dependent input signal splitting and phase alignment between the main and auxiliary branches, thus allowing to overcome several shortcomings of traditional analog Doherty amplifiers. The proposed analysis focuses on the gain and efficiency performance over a 6 dB back-off range. The comparison over the 3.1-3.7 GHz range shows a superior performance of the digital DPA over the analog one, thus justifying the additional.