Investigation of the Effect of Weak Non-Linearities on P1dB and Efficiency of Class B/J/J* Amplifiers

Abstract

The variation of phase of the current through the non-linear intrinsic capacitances of a high-power RF device caused by the variation of the phase in the continuum of drain voltage waveforms in Class B/J/J* leads to a reduction of intrinsic drain current when moving from class B to class J* while the drain current increases from class B to class J. Consequently, a subset of voltage waveforms of the class B/J/J* continuum can be used to design amplifiers with higher P1dB, and efficiency at P1dB than in Class B. A simple choice of this subset is demonstrated with a 2.6 GHz Class B/J/J* amplifier, achieving a P1dB of 38.1 dBm and PAE at P1dB of 54.7%, the highest output power and efficiency at P1dB amongst narrowband linear amplifiers using the CGH40010 reported to date, at a comparable peak PAE of 72%.