A 65-W high-efficiency UHF GaN power amplifier

This paper presents a high-efficiency UHF power amplifier (PA) using a GaN HEMT on a SiC substrate transistor as the active device. The PA delivers 65W with 82% power added efficiency (PAE), and 45W with 84% PAE at 370MHz, with supply voltages of 35V and 28 V, respectively. Load pull techniques under Class-E conditions are used for device characterization and matching network design. The PA is implemented in a hybrid circuit with mixed lumped-element and transmission-line matching networks. A weighted Euclidean distance is defined to enable tradeoff studies between output power (P
OUT
) and efficiency, in order to find the final optimal amplifier design.