GaN Doherty MMIC Power Amplifiers for Satellite Ka-band Downlink

This work presents the design and preliminary results of two integrated Doherty power amplifiers fabricated on 100nm Gallium Nitride on Silicon, targeting the satellite downlink Ka-band (17.3–20.3 GHz). The MMICs, based on different architectures, have been designed respecting the stringent limits on linearity and devices’ maximum junction temperature imposed by the application. Nevertheless, an average output and efficiency higher than 36dBm and 30%, respectively, are expected across the overall band. The preliminary characterization of the MMICs shows measured small signal behaviours well in agreement with the simulations. In particular, for both MMICs, the measured small signal gain is in excess of 25 dB with both input and output return losses better than 10 dB in the whole frequency band.