Highly efficient carrier bursting RF transmitter employing direct band pass filter connection

Modern communication standards have high peak to average power ratios (PAPR) to achieve high spectral efficiency, trading of poor power amplifier (PA) efficiency. Carrier bursting PAs can improve efficiency. The properties of a carrier bursting PA and the concept of direct filter connection are briefly discussed. Based on combining the advantages of the carrier bursting PA and the direct filter connection, a concept for a highly efficient PA operation using PWM modulation of the drain voltage is proposed. By introducing a PA with two DC voltage levels it is possible to reach high coding and drain efficiency at the same time. Additionally the requirements and effects of the filter impedance at the modulation sidebands are analyzed.