A Novel High Efficiency Power Amplifier Concept for GSM Handsets
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European Conference on Wireless Technology ECWT, London, Sept. 27-28, 2001
The demand for ever increasing talking times and reduced weight of modern GSM handsets can only be achieved by a significant reduction of the power consumption of the cellular handset, mostly the power amplifier (PA). The constant envelope modulation scheme of the GSM system allows the design of high efficiency power amplifiers, such as switching amplifiers. Among them, the Class-E amplifier concept is best suited, because it allows about 80% efficiency, while maintaining an excellent output spectrum and reasonable gain. Another advantage is the possibility to an a-priori design and characterization of the amplifier stage by simulation. This fact is demonstrated in this paper, by comparing simulation and measurement results of a 45-MHz Class-E amplifier as a 1:20 frequency scaled model of a 900-MHz GSM power amplifier. The excellent match between theory and measurement allows a good prediction of the final Class-E amplifier characteristics by simulation.