High efficiency push-pull inverse class F power amplifier using a balun and harmonic trap waveform shaping network

Abstract

We present the desi g n and development of a push pull inverse class F power amplifier in X band usin g a novel harmonic matchin g network. The harmonic matchin g network is realized by a simple, low-loss, Marchand balun and a harmonic trap circuit.This novel harmonic matching network not only provides 3-dB power combinin g , but also enables waveform shapin g for enhanced efficiency. This I-sta g e power amplifier using discrete GaAs pHEMTs achieves a measured saturated output power of 33 dBm with a power added efficiency of 63% and a g ain of 10 dB. This amplifier operates at 10 GHz with a 6% fractional bandwidth.Index Terms -Power amplifiers, power FET amplifiers, microwave power amplifiers, MODFET power amplifiers, power combiners.

Common-mode termination requirements in concurrent dual-band push-pull power amplifiers

“…This thesis provides an overview of the different problems that can occur in push-pull amplifiers when engineers attempt to drive it with two or more carriers simultaneously. In applications requiring high output power and high efficiency a push-pull switched-mode amplifier would be an appropriate choice giving an added 3 dB of maximum output power while also reducing noise from even harmonics [8,9]. The final output from an amplifier can be required to be singleended, for either an antenna, or other signal processing stages.…”

“…As has been stated earlier the ability to consolidate multiple carriers onto a single RF path would be highly desirable in today's over-crowded front-end module designs. However, dualcarrier PA's have yet to be widely researched, there have been some papers published that go over their design but they generally only cover single-ended architectures [8,18], Or they might only cover concurrent band impedance matching [17,28], It's important to note however that management of the intermodulation components for increased efficiency has been done but only in single-band [9]. Although these researchers are using them for waveform shaping of the output to improve efficiency.…”