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Design and performance of multi-channel switched sequential amplifiers

Published online by Cambridge University Press:  19 June 2009

Thomas Lehmann  and
Reinhard Knoechel
Thomas Lehmann*
Affiliation:
Institute of Electrical and Information Engineering, Microwave Laboratory, University of Kiel, Kaiserstrasse 2, 24143 Kiel, Germany. Phone: +494318806167; Fax: +494318806152.
Reinhard Knoechel
Affiliation:
Institute of Electrical and Information Engineering, Microwave Laboratory, University of Kiel, Kaiserstrasse 2, 24143 Kiel, Germany. Phone: +494318806167; Fax: +494318806152.
*
Corresponding author: T. Lehmann Email: tl@tf.uni-kiel.de
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Abstract

This paper presents switched sequential amplifiers (SSAs) using reconfigurable directional couplers as power splitters and combiners. The SSA concept allows matching the efficiency characteristics to the amplitude probability density distribution of the applied modulated signal. Therefore the back-off efficiency can be increased significantly. A three-channel SSA can e.g. theoretically achieve a −10 dB back-off efficiency exceeding 50%. Design parameters and potential efficiency enhancement are discussed for two- and three-channel SSAs. After a brief introduction of the used switched couplers, the circuit concept for two- and three-channel SSAs is described. Calculations for the possible efficiency enhancement are presented. Also signal distortions by the directional couplers are outlined. The paper closes with experimental results for a two-channel SSA.

Keywords

EfficiencyReconfigurable architecturesrf power amplcifiersCouplers
Type
Original Article
Information
International Journal of Microwave and Wireless Technologies , Volume 1 , Special Issue 4: European Microwave Week 2008 , August 2009 , pp. 269 - 275
Copyright
Copyright © Cambridge University Press and the European Microwave Association 2009

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References

REFERENCES

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