Dual-mode dual-band symmetrical doherty power amplifier employing reciprocal gate bias for high-efficiency range enhancement

This article presents an in-depth exploration of the circuit architecture and design approach for broadening the high-efficiency range of dual-mode symmetrical Doherty power amplifiers (DPAs). To enhance performance across a broader spectrum, a modified dual-mode load modulation network (LMN) is introduced, leveraging the reciprocal gate bias configuration to support an expanded high-efficiency range exceeding 6 dB across two distinct operational bands. To corroborate the efficacy of our proposed dual-mode symmetrical DPA architecture, we designed and constructed a prototype power amplifier (PA) utilizing commercially available GaN transistors. The implemented PA demonstrates exceptional performance, achieving two distinct Doherty operation bands, specifically 1.85-2.0 GHz in Mode I and 1.5-1.55 GHz in Mode II. Remarkably, the high-efficiency range is extended to 8 dB in both bands. Furthermore, the drain efficiency achieves levels of 48.5%–51.8% in Mode I and 47.7%–50.4% in Mode II at 8 dB back-off, with a saturated output power exceeding 43 dBm.