Outphasing transmitters, enabling digital-like amplifier operation with high efficiency and spectral purity

An overview of outphasing transmitters is given. Starting from its basic principles, we discuss its advantages and drawbacks compared to other high-efficiency amplifier configurations. Next, innovations in outphasing architecture, design, and implementation are given that overcome the difficulties related to the traditional outphasing configuration. Using the latest insights in drive schemes for input signals and quasi load-insensitive class-E output matching, very compact high-power high-performance digital- like transmitters are enabled that offer high efficiency and high spectral purity while being reconfigurable in their operating frequency.