Continuously Reconfigurable and High-Efficiency 70 W Power Amplifiers for 1–5 GHz

Abstract

Two continuously reconfigurable and high-efficiency 1–5 GHz, 70 W, Class AB power amplifiers (PAs) are introduced and experimentally investigated in this article. Both designs use gallium nitride (GaN) high electron mobility transistors (HEMTs) and coupled high quality factor (high-Q) evanescent-mode (EVA) cavity resonators for their output matching networks (OMNs). The first design is partially reconfigurable, with a traditional static input matching network (IMN), while the second design is fully reconfigurable, using a single high-Q EVA cavity resonator for its IMN. Each cavity has a piezoelectric bending actuator to independently change its resonant frequency. Both reconfigurable matching network designs provide optimal impedances to the transistor over a wider range of frequencies than traditional matching networks, significantly outperforming static matching amplifier designs and achieving state-of-the-art performance. Large signal gain is above 10 dB for the entire frequency range at the maximum output power of 48.5 dBm. The drain efficiency of the partially reconfigurable design peaks at 74% and is above 50% from 1 to 4 GHz, dropping to 30% by 5 GHz. In the fully reconfigurable design, the drain efficiency peaks at 75% and stays above 50% for the entirety of the 1–5 GHz range. Compared to existing technologies, this performance exhibits a broader frequency range and higher output power, while maintaining similar percentages for drain efficiency.