Efficient Multisignal 2–4-GHz Power Amplifier With Power Tracking

Abstract

The goal of the work presented in this paper is to demonstrate an efficient method of amplifying multiple concurrent signals over a large bandwidth using a supply modulation approach. A single-stage octave bandwidth (2–4 GHz) power amplifier (PA) with greater than 10-W output power and drain efficiency ranging from 48%–60% is presented. The amplifier is tested with several reduced-bandwidth supply modulation trajectories that are constructed as an even-termed power series of a 10-MHz LTE signal envelope. A greater than 30% point increase in $\eta _{D}$ is achieved while maintaining less than −45-dB ACPR with digital predistortion (DPD). Two 10-MHz LTE signals with 800-MHz spacing are then amplified using a similar bandwidth-reduction technique. A greater than 20% point increase in $\eta _{D}$ is seen with an improvement in linearity through the use of multidimensional DPD. The method presented here can be extended to more than two concurrent signals of arbitrary spacing for a PA with large RF bandwidth.