Simple Analog Pre-Distorter Design with Controllable AM/AM and AM/PM Distortion

This paper presents a novel design of Analog Predistorter (APD) based on two forward-biased PIN diodes and transmission lines only. The proposed topology offers tuneable gain expansion (2-5 dB) with low phase distortion ($<3^{\circ}$). For suppression of AM/PM distortion, inductive compensation technique is introduced. This APD features circuit simplicity, compact size, low insertion loss, high return loss, and wideband. For validation, the measured linearity performance of a 2 GHz APD circuit under single- and two-tone excitation are shown.