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Continuous-classF3 power amplifier mode varying simultaneously first 3 harmonic impedances

 
: Carrubba, V.; Quay, R.; Schlechtweg, M.; Ambacher, O.; Akmal, M.; Lees, J.; Benedikt, J.; Tasker, P.J.; Cripps, S.C.

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Institute of Electrical and Electronics Engineers -IEEE-:
IEEE MTT-S International Microwave Symposium, IMS 2012 : 17-22 June 2012, Montreal, QC, Canada
New York, NY: IEEE, 2012
ISBN: 978-1-4673-1088-8
ISBN: 978-1-4673-1085-7 (Print)
ISBN: 978-1-4673-1086-4 (Online)
ISBN: 978-1-4673-1087-1
3 pp.
International Microwave Symposium (IMS) <2012, Montréal>
English
Conference Paper
Fraunhofer IAF ()
broadband amplifiers; gallium nitride; microwave device; microwave measurement; power amplifiers

Abstract
This paper presents for the first time the broadband Continuous-ClassF3 mode power amplifier (PA) extended to include a variable reactance third harmonic impedance. It will be demonstrated that by proper manipulation of the voltage and current waveforms different optimum impedance solutions can be identified. When designing PAs, the harmonic impedances cannot easily be constraint to open-circuit and/or short-circuit points with varying frequency. Therefore, the possibility to vary the third harmonic reactance as well as the second harmonic and fundamental reactance with frequency would allow for an easier, more flexible and achievable design requirement. Measurements on a GaN power transistor have delivered around 34.5-35.9 dBm of output power, 80-85 % of drain efficiency and 13.7-15.5 dB of available gain at 1 GHz of fundamental frequency for the various combination of first three load solutions. The measurements demonstrate that constant or greater output performance can be obtained over a wide PA design space when varying properly the first three harmonic loads. The different reactive impedance solutions carried out at the single frequency can then be translated into frequency domain, allowing the design of high power-efficiency broadband power amplifiers.

: http://publica.fraunhofer.de/documents/N-217201.html