Efficiency Enhancement of Pico-cell Base Station Power Amplifier MMIC in GaN HFET Technology Using the Doherty technique

Abstract 1 With the growth of smart-phones, the demand for more broadband, data-centric tech-nologies are being driven higher. As mobile operators worldwide plan and deploy 4th genera-tion (4G) networks such as LTE to support the relentless growth in mobile data demand, the need for strategically positioned pico-sized cellular base stations known as ‘pico-cells ’ are gaining traction. In addition to having to design a transceiver in a much compact footprint, pico-cells must still face the technical challenges presented by the new 4G systems, such as reduced power consumptions and linear amplification of the signals. The RF power amplifier (PA) that amplifies the output signals of 4G pico-cell systems face challenges to minimize size, achieve high average efficiencies and broader bandwidths while maintaining linearity and operating at higher frequencies. 4G standards as LTE use non-constant envelope modulation techniques with high peak to average ratios. Power amplifiers implemented in such applications are forced to operate at a backed off region from satura-tion. Therefore, in order to reduce power consumption, a design of a high efficiency PA tha