A Ka-band Doherty Power Amplifier using an innovative Stacked-FET Cell

This paper presents an innovative stacked-FET cell useful to enhance both, gain and output power of RF and mm-wave power amplifiers. The new structure has been validated through the design of a downlink Ka-band Doherty Power Amplifier. The resulting module is a two stages Microwave Monolithic Integrated Circuit (MMIC) fabricated on a commercial 100nm gate length Gallium nitride on Silicon technology. The design was carried out to satisfy not only the power requirements but also to meet the thermal constraints for space use. Simulation results have shown a power added efficiency (PAE) greater of 30% at 6dB of output power back-off with a peak of output power of 38dBm inside the operative band, from 17.3 GHz to 20.3 GHz. Whereas, a saturated gain above 17dB has been achieved with a gain flatness better than 0.5dB in the overall band. The chip area is 5x3.7mm(2).