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http://dx.doi.org/10.5573/JSTS.2007.7.4.274

Efficiency Improvement of HBT Class E Power Amplifier by Tuning-out Input Capacitance  

Kim, Ki-Young (School of Engineering, Information and Communications University)
Kim, Ji-Hoon (School of Engineering, Information and Communications University)
Park, Chul-Soon (School of Engineering, Information and Communications University)
Publication Information
JSTS:Journal of Semiconductor Technology and Science / v.7, no.4, 2007 , pp. 274-280 More about this Journal
Abstract
This paper demonstrates an efficiency improvement of the class E power amplifier (PA) by tuning-out the input capacitance ($C_{IN}$) of the power HBT with a shunt inductance. In order to obtain high output power, the PA needs the large emitter size of a transistor. The larger the emitter size, the higher the parasitic capacitance. The parasitic $C_{IN}$ affects the distortion of the voltage signal at the base node and changes the duty cycle to decrease the PA's efficiency. Adopting the L-C resonance, we obtain a remarkable efficiency improvement of as much as 7%. This PA exhibits output power of 29 dBm and collector efficiency of 71% at 1.9 GHz.
Keywords
Class E; hetero-junction bipolar transistor; monolithic microwave integrated circuit; power amplifier;
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