This thesis addresses the analytical modeling and design of a high-efficiency radio-frequency (RF) power amplifier (PA) architecture that combines the advantages of Class-E switching operation and Doherty load modulation. The work is motivated by the increasing demand for energy-efficient RF transmitters in modern wireless communication systems, where high peak-to-average power ratios (PAPR) impose stringent efficiency requirements not only at saturation but also in back-off conditions. A power amplifier represents the final stage of the RF transmission chain and plays a decisive role in determining overall transmitter performance, particularly in terms of efficiency, linearity, and thermal management. Among high-efficiency topologies, Class-E amplifiers are switching-mode PAs capable, under ideal conditions, of achieving 100% efficiency.