Class-S Amplifier at 450 MHz Using GaN-HEMT Power Switch MMICs

C. Meliani, A. Wentzel, J. Flucke, E. Ersoy, N. Chaturvedi, R. Lossy, F. Schnieder, B. Janke, S. Freyer, H.-J. Würfl, and W. Heinrich

Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Strasse 4, 12489 Berlin, Germany

Published in:
Frequenz, vol. 63, no. 3-4, pp. 55-59 (2009).
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Abstract:
This paper reports on the realization and characterization of GaN-HEMT based power-switch MMICs suitable for class-S operation. The amplifier operates in the 500 MHz band with a sampling bit-rate of 1.8 Gbps. For digital signals (at 1.8 Gbps) without output filtering, the realized GaN MMICs achieve efficiencies of more than 90% at 5.4W output power with PAE values of 80% including the on-chip drivers. The MMICs have been used to set up a complete class-S amplifier. A first realization achieves 2.7W output power with an overall effi-ciency of 19%.

Index Terms:
GaN, HEMT, power amplifier, switch-mode, class-S, delta-sigma, time domain.

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