Dual-band Linear Filter Assisted Envelope Memory Polynomial for Linearizing Multi-band Power Amplifiers

This paper proposes a dual-band linear filter assisted envelope memory polynomial model (EMP) devised for analog-RF predistortion (ARFPD) systems. The proposed model consists of two finite-impulse-response (FIR) filters preceding a newly formulated dual-band EMP block in forming the pruned 2D-FIR-EMP model. A linear estimation algorithm is devised to identify the coefficients of the proposed pruned 2D-FIR-EMP model. Furthermore, a proof of concept of the digitally-assisted dual-band ARFPD system based on two RF vector multipliers (RF-VM) built using off-the-shelf (OTS) components is presented. Measurement results obtained using the proposed pruned 2D-FIR-EMP proof-of-concept predistorter has demonstrated excellent linearization results in compensating for the distortions exhibited by a gallium nitride Doherty power amplifier driven by dual-band signals.