Modeling and Digital Suppression of Passive Nonlinear Distortion in Simultaneous Transmit—Receive Systems

Abstract

In frequency division duplexing (FDD) based simultaneous transmit-receive systems, nonlinear behavior of the active and passive RF components can cause nonlinear distortion products falling at the receiver band. Such distortion may also arise over-the-air, if there are for example metallic objects in close vicinity of the antenna system. In this work, we focus on the modeling and digital cancellation of such distortion products, especially in case of passive harmonic distortion of the transmit waveform landing at the receiver band. We provide behavioral modeling of the problem, while also use the models to derive corresponding digital distortion cancellers. Practical RF measurement based numerical results are provided, focusing on a timely dual-band cellular transceiver scenario covering 5G NR bands n3 (1.8 GHz) and n78 (3.5 GHz). The RF measurement results demonstrate accurate modeling and distortion cancellation in the considered example cases.