The Doherty Amplifier continues to be rolled out in an increasing number of TxFE (Transmit Frontend) applications, as the quasi-linear amplifier architecture of choice. The advent of 5G, with its inevitable microwave or millimeter wave air interface, increase the design challenges associated with its construction; not least of all because of the potential for increased dispersion in the constituent amplifiers and combiners.
This application note describes a measurement-based development methodology by which the Doherty Amplifier may be enhanced, increasing performance and/or performance bandwidth. This methodology is supported with a working example.
The methodology may also be extended to balanced, spatially combined and anti-phase (so called "pushpull" or "differential") amplifiers, the latter often itself nested in Doherty configurations.
