Vol. 37

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2013-01-24

Study of the Inter-Stage Capacitor Effects of a RF CMOS Power Amplifier to Enhance its Efficiency

By Hoyong Hwang, Donghwan Seo, Jonghoon Park, and Changkun Park
Progress In Electromagnetics Research C, Vol. 37, 29-40, 2013
doi:10.2528/PIERC12122806

Abstract

In this work, we analyze the effects of an inter-stage capacitor located between the power stage input and the driver stage output on the overall efficiency of a RF CMOS power amplifier and on gate-drain reliability problems. To verify the analyzed effects, we designed a RF CMOS power amplifier with a center frequency of 1.85-GHz. Class-D amplifiers with a feedback resistor are used as driver stages, and a class-E amplifier is used as the power stage. A distributed active transformer is adapted for use in the output power combiner for high efficiency. The inter-stage capacitor between driver and the power stage is removed to enhance the switching operation of the power stage. By eliminating the inter-stage capacitor, the supply voltage of the driver stage can be decreased compared to that in a general amplifier. Accordingly, the power-added efficiency is improved and the gate-drain reliability problems are moderated compared to a general amplifier. The analyzed effect of the inter-stage capacitor is verified successfully using the measured results of the designed amplifiers.

Citation


Hoyong Hwang, Donghwan Seo, Jonghoon Park, and Changkun Park, "Study of the Inter-Stage Capacitor Effects of a RF CMOS Power Amplifier to Enhance its Efficiency," Progress In Electromagnetics Research C, Vol. 37, 29-40, 2013.
doi:10.2528/PIERC12122806
http://jpier.org/PIERC/pier.php?paper=12122806

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