Load insensitive power amplifiers

The advent of fifth-generation (5G) wireless networks and their successors is poised to significantly enhance global economic productivity and societal connectivity. Central to this advancement is the power amplifier (PA), a critical component in radio frequency (RF) front-ends, which must efficiently amplify wideband OFDM signals with high peak-to-average power ratios (PAPR) under varying load conditions. Traditional PA designs rely on isolators to mitigate load sensitivity, but these are unsuitable for compact or high-frequency applications due to integration and cost constraints. This dissertation addresses the challenge of PA load resilience by introducing circuit topologies and adaptive techniques that eliminate the need for isolators. Key innovations include passive orthogonal impedance sensing, self-healing PA designs, and load-insensitive Doherty and inverse Doherty amplifiers. A standout contribution is a PA correction method using only active devices—without tunable networks or supply adjustments—ideal for high-power or fast-changing environments. These solutions are validated through PCB demonstrators, offering a path toward more efficient and resilient RF front-ends for future wireless systems.