L-Band Digital Doherty SSPA Design for Compact SATCOM Terminal Applications

A GaN based dual-input digital Doherty power amplifier is demonstrated for small SATCOM terminals for use in lightweight UAV applications. A novel algorithm is presented that helps operate the Doherty power amplifier at optimum conditions in terms of efficiency and/or linearity. Digital pre-distortion linearization is deployed together with the digital Doherty to achieve low spectral regrowth in narrowband satellite uplink.