Packaged Floating-Ground RF Power GaN-HEMT

This paper presents a novel packaged RF power GaN-HEMT for floating-ground operation. A bondable single-layer capacitor is mounted in the package close to the transistor chip to provide the low inductance RF bypass to ground, i.e., the flange, while a third lead is connected to the transistor-chip source terminal and facilitates the connection of the floating DC and low frequency (LF) ground-supply. The performance of the transistor is evaluated by 3-port S-parameter and load-pull measurements. S-parameters show large impact on stability from the floating operation. At 40 V and 1.4 GHz the transistor delivers up to 51 W saturated output power, demonstrating similar performance as a standard transistor of the same size. The floating LF ground facilitates a modulation bandwidth of up to 300 MHz, making the floating-ground transistor an interesting candidate for, e.g., reverse-type envelope tracking topologies.