A 1.6-2.2 GHz Continuous Class-B/J GaN HEMT Power Amplifier with Drain Efficiency Over 70%

Continuous Class-B/J amplifiers, capable of achieving a drain efficiency (DE) of 78.5% across a wide frequency range, have been extensively studied. However, practical implementation has posed challenges in managing the load impedances as prescribed by theory, resulting in significant DE fluctuations. This study addresses the issue by (1) analyzing the impact of FET parasitic elements on load impedances and (2) considering higher-order harmonics, which were not considered in the original theory. The proposed design method was validated through the development of a 10W GaN HEMT power amplifier, demonstrating a DE exceeding 70% over a bandwidth of 1.6-2.2 GHz.