Two Stage GaN HEMT Amplifier With Gate Source Voltage Shaping for Efficiency Versus Bandwidth Enhancements.

Alaaeddine Ramadan (1) , Tibault Reveyrand (1) , Audrey Martin (1) , Jean-Michel Nebus (1) , Philippe Bouysse (1) , L. Lapierre (2) , J.F. Villemazet (3) , S. Forestier

1 C2S2
2 CNES - Centre National d'Études Spatiales [Toulouse]
3 TAS - Thales Alenia Space [Toulouse]

In this paper a two-stage 2-GHz GaN HEMT amplifier with 15-W output power, 28-dB power gain, and 70% power-added efficiency (PAE) is presented. The power stage is designed to operate under class F conditions. The driver stage operates under class F-1 conditions and feeds the power stage with both fundamental and second harmonic components. The inter stage matching is designed to target a quasi-half sine voltage shape at the intrinsic gate port of the power stage. The goal is to reduce aperture angle of the power stage and get PAE improvements over a wide frequency bandwidth. In addition to the amplifier design description, this paper reports original time-domain waveform measurements at internal nodes of the designed two-stage power amplifier using calibrated high-impedance probes and large signal network analyzer. Furthermore, waveform measurements recorded at different frequencies show that aperture angle remains reduced over large frequency bandwidth. In this study, a PAE greater than 60% is reached over 20% frequency bandwidth.

Alaaeddine Ramadan, Tibault Reveyrand, Audrey Martin, Jean-Michel Nebus, Philippe Bouysse, et al.. Two Stage GaN HEMT Amplifier With Gate Source Voltage Shaping for Efficiency Versus Bandwidth Enhancements.. IEEE Transactions on Microwave Theory and Techniques, 2011, 59 (3), pp.699-706. ⟨10.1109/TMTT.2010.2095033⟩. ⟨hal-00700232⟩