A 10-W X-Band Class-F High-Power Amplifier in a 0.25-μm GaAs pHEMT Technology

Abstract

In this article, a design methodology is presented to realize integrated class-F high-power amplifiers (HPAs). A harmonic-control network (HCN) is proposed to present short- and open-circuit impedances to each transistor employed in the output stage of the HPA at 2f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> and 3f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> frequencies. The HCN absorbs the parasitic capacitance of the transistor and lends itself to be absorbed in the matching and power combiner networks, reducing the die area of the HPA. A proof-of-concept 9.7-10.3-GHz class-F HPA was designed and implemented in a 0.25-μm GaAs pHEMT technology with VDD of 6 V. The designed HPA consists of two amplifying stages, and its output stage includes 16 transistors in parallel to provide 39-40-dBm output power. The class-F HPA achieves a 10-W output power and a peak power added efficiency (PAE) of 63% for pulsed-mode operation with a pulse repetition frequency (PRF) of 1 kHz and a duty cycle of 10%. The measured peak output power and PAE in the continuous-wave (CW) operation are 9.3 W and 58%, respectively.