RF Leakage Compensation in Wideband Envelope Tracking Power Amplifiers for Mobile Terminals

This paper presents a new linearization method to compensate for the unwanted RF leakage that appears at the ouput of envelope tracking modulators (ETMs) when operating envelope tracking (ET) power amplifiers (PAs) with wideband signals. This RF leakage is combined in the ETM with the dy-namic supply signal and generates unwanted nonlinear distortion at the RF output of the ET PA. A leakage cancellation method based on an envelope generalized memory polynomial (EGMP) behavioral model is proposed to compensate for this unwanted distortion. The linearization method is validated on a system-on-chip ET PA board designed by Hisilicon for mobile applications. Thanks to the proposed cancellation technique, it is possible to meet the out-of-band linearity requirements when considering a 60 MHz bandwidth new radio OFDM-like signal at band 7.