Discrete Tunable RF-Power GaN-BST Transistors

O. Bengtsson¹ , H. Maune², F. Gölden³, S. Chevtchenko¹, M. Sazegar², P. Kurpas¹, A. Wiens², R. Jakoby², and W. Heinrich¹

¹ Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
² Institute for Microwave Engineering and Photonics, Technische Universität Darmstadt, Darmstadt, Germany
³ SHF Communication Technologies AG, Wilhelm-von-Siemens-Str. 23 D, Berlin, Germany

Published in:
9th European Radar Conf. (EuRAD 2012), Amsterdam, The Netherlands, Oct. 28 - Nov. 2, pp. 377-380 (2012).
© Copyright 2012 IEEE - All Rights Reserved. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

Abstract:
In this work the current status of a novel Barium- Strontium-Titanate (BST) based discrete tunable RF-power GaN-HEMT transistor is presented. A p-design prototype is evaluated for tunable networks in a load-pull investigation at 0.9 GHz, 1.3 GHz, and 2.0 GHz. It is shown that the individual GaN-cell BST networks can handle more than 2 W output power but the network losses reduce the drain efficiency by 10...35 percentage points. The BST losses are found to be extremely frequency dependant under power operation but the linearity of the device is dominated by the non-linearity of the transistor itself. Present limitations and development areas of this novel concept are discussed in the work.

Keywords:
Tunable Components, Gallium Nitride, Ferroelectrics, Power Amplifiers, Adaptive Matching.

Full version in pdf-format.