Individual source vias for GaN HEMT power bars

In this paper the layout concept based on individual source vias (ISV) is introduced and investigated for GaN HEMT power bar transistors. The influence of the source inductance on the gain parameters as well as on the stability is shown. The layout concept is described and small-signal measurements confirm the improvement of the gain as compared to a microstrip transmission line (MSL) concept. Measurements on packaged power bars show the benefit of ISV layouts both in terms of stability point and gain as well as P(out) and PAE. Such measurements show PAE values of 70% in package and high gain values of 20.5 dB while delivering 106 W of output power at 2 GHz.