K-band combined GaAs monolithic Doherty power amplifier

Abstract

This paper presents the design, simulations, and measurements of a 35 dBm K-band Doherty power amplifier, fabricated on 0.15μm GaAs monolithic technology of Qorvo. The power amplifier is based on combining on-chip two Doherty modules with a matching power combiner. To demonstrate the power scaling and gain a better insight into the design, the single Doherty module has been fabricated and characterized as well. The Doherty output matching is designed for maximizing the bandwidth and minimizing the components count, with the output capacitance of the active devices determining the impedance inverter impedance. The combined Doherty shows an output power of 35 dBm at 24 GHz, that is almost exactly 3 dB larger than the single Doherty module power module, and with a 6 dB OBO efficiency of 27%, and a gain of 11.5dB. It compares well with the state of the art, representing the highest power GaAs Doherty at similar frequencies.