GaN-on-Si switched mode RF power amplifiers for non-constant envelope signals

This work implements three discrete switched mode power amplifier (PA) topologies, namely inverse class-D (CMCD), push-pull class-E and inverse push-pull class-E, in a GaN-on-Si process for medium power level (5-10W) femto/pico-cells base-station applications. The designs are analyzed and compared with respect to non-idealities such as bond-wire effects and input signal duty cycle variation. These architectures are designed for non-constant envelope inputs in the form of digitally modulated signals such as RFPWM, which undergoes duty cycle variation. After comparing the three topologies, this work concludes that an inverse push-pull class-E architecture gives highest output power and efficiency for GaN-based discrete power amplifiers. This inverse class-E PA achieves 61.5% drain efficiency at 37.7dBm output power in the 880MHz band.