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

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 ηD 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 ηD 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.