Analysis and Design of Ultrawideband Generalized Asymmetrical Doherty Power Amplifier Using Hybrid Voltage–Current Configuration

This article presents a theoretical analysis and design methodology for a high-efficiency broadband generalized asymmetric Doherty power amplifier (G-ADPA). The proposed architecture optimizes power distribution and load modulation characteristics through a hybrid configuration of asymmetric transistor currents and asymmetric drain supply voltages, thereby enhancing efficiency across a wide operational bandwidth. Furthermore, this article provides a general method for determining the network parameters of G-ADPA architecture along with analytical solutions for each network parameter, as well as the corresponding circuit design approach. To validate the effectiveness of the proposed G-ADPA architecture and design approach, a prototype operating from 0.7 to 2.1 GHz with 100% fractional bandwidth was fabricated on Rogers RO4350B substrate. Under continuous wave (CW) measurements, the fabricated G-ADPA achieves an efficiency of 43.5%–58.0% at 7-dB power back-off (PBO) and 50.9%–74.5% at saturation. To further assess its applicability in practical communication scenarios, tests were conducted using a 20-MHz 64-QAM signal with a 7-dB peak-to-average power ratio (PAPR). At an average output power of approximately 34 dBm, the drain efficiency (DE) exceeds 43.1%, while the adjacent channel power ratio (ACPR) remains better than −51.6 dBc after digital predistortion (DPD).